Keep or Replace Eaton Rear End - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jahloha · 11-13-2013, 01:11 PM

I have a 1970 C20 with an Eaton rear end. I read everywhere on this site that the Eaton is a rock and if kept taken care of, will last forever.

But

I also read that parts for this rearend are very rare to find and purchase.

So being untaught, what parts are hard to find?

I hoping to do a disc swap on both the front and back...would this resolve the difficulty of finding these parts?

Thanks for the insight.

c20pickup · 11-13-2013, 03:34 PM

the eaton is a tank, there are a few nice things about it, removable third member and also the rigidity of it. but that's about where the pros end. the hard parts to find for it, are basically everything, seals, bearings, brake parts, gear sets, hubs, lockers, etc. people have adapted the eaton to use 14 bolt backing plates and then Cadillac calipers to convert to discs brakes. also the option of lockers is also limited, seems as if you can find a factory "no-spin" lockers (very rare, and frankly overpriced for a used locker, ive looked into it) or you can use a locker out of a 14 bolt, but then you have to use 14 bolt axle shafts and shave them down 1/4 inch to accept the third member. in my opinion I would replace he axle with a dana 60 or a 14bolt, just for the fact that when it needs to be serviced, its not a hodge podge of parts all stuck together that needs to be custom made. and at what point, after changing all the internals and brake parts does a eaton remain an eaton? and at what point would it be easier to swap in something that already has discs and a locker. im open to questions, been doing a lot of researched on these axles lately. good luck!

Longhorn 70 · 11-13-2013, 08:30 PM

Bearings, brake parts, hubs, pinion supports and so on are kinda hard to find and pricey when you do. If it isn't a show truck, drive the Eaton until it breaks, if it ever does. THEN 14 bolt FFs are easy to find reasonable. Easy to change and adapt. Another big plus to the 14BFFs is there are more gear ratios available.

If it is a showgo, then get the prettiest and bolt it up.

My HO52 has over 450K miles on it and all I have really done is keep it lubed and seal leaks. I have POUNDED that thing with torque and carried, not many, heavy loads from time to time. It has also been when I was young and dumb, used at high speeds. It isn't pretty but it works.

Jahloha · 11-13-2013, 09:16 PM

Quote:

Originally Posted by Longhorn 70

Bearings, brake parts, hubs, pinion supports and so on are kinda hard to find and pricey when you do. If it isn't a show truck, drive the Eaton until it breaks, if it ever does. THEN 14 bolt FFs are easy to find reasonable. Easy to change and adapt. Another big plus to the 14BFFs is there are more gear ratios available.

If it is a showgo, then get the prettiest and bolt it up.

My HO52 has over 450K miles on it and all I have really done is keep it lubed and seal leaks. I have POUNDED that thing with torque and carried, not many, heavy loads from time to time. It has also been when I was young and dumb, used at high speeds. It isn't pretty but it works.

Longhorn:

Good to chat with you again. Quick question, if I said this was going to be a daily driver where MPG matters to me, would that change your mind at all regarding the swap?

I really am concerned about parts accessibility 5, 10, 15 years down the road; but durability is always a concern. So wheres the line for you to make the swap or not?

Thanks again.

PS...I also consider this an option for the rear disc swap that I have asked you about before.

swamp rat · 11-13-2013, 10:28 PM

You can get all the bearings, seals and even the felt pinion seal for the diff thru Randys Ring and Pinion in Seattle, That includes the big pinion bearing but it is expensive.

Wheel hub bearings and seals can be bought at the auto parts store, the only replacements are tapered roller bearings instead if the Barrel bearings.

Brake parts can be found but don't all come easy, the shoes can be relined if necessary, i think even the drums can still be found.

You can use a conversion bracket for a 14 bolt disk conversion on the Eaton, some places market one for the Eaton too.

Front rotors and calipers from a 72 4X4 will work on the rear, so it should be the same on a C20, just know there are light duty and heavy duty rotors and calipers, you do want the heavy duty stuff, 1" thick rotors are light duty, 1 1/4" thick rotors are heavy duty.

**special-K** · 11-14-2013, 08:54 AM

Do what those of us who have driven older vehicles daily have always done...get the parts now while you can and have them ready for the day you might possibly need them. If not,years down the road you'll have parts no one else can get to sell when you move on. Or,you could buy the parts,install them,whether they need it or not,and be good to go. Parts may be higher on these,but they aren't cheap on a 14-bolt and,unless someone gives you one already altered to go under a 67-72,you're looking at some expense there. If you do discs,your only concern is wheel bearings. Even if those go extinct from parts stores,I've found you can usually find bearing by dimension from a bearing distributor. Also,14-bolt brakes can be fitted up to an HO52 Corporate rear.

Or,you could just run it,maintain it,and not worry about the rare chance a problem will occur. These rears are under GM Trucks dating back into the '40s

Jahloha · 11-14-2013, 10:36 AM

Quote:

Originally Posted by special-K

Do what those of us who have driven older vehicles daily have always done...get the parts now while you can and have them ready for the day you might possibly need them. If not,years down the road you'll have parts no one else can get to sell when you move on. Or,you could buy the parts,install them,whether they need it or not,and be good to go. Parts may be higher on these,but they aren't cheap on a 14-bolt and,unless someone gives you one already altered to go under a 67-72,you're looking at some expense there. If you do discs,your only concern is wheel bearings. Even if those go extinct from parts stores,I've found you can usually find bearing by dimension from a bearing distributor. Also,14-bolt brakes can be fitted up to an HO52 Corporate rear.

Or,you could just run it,maintain it,and not worry about the rare chance a problem will occur. These rears are under GM Trucks dating back into the '40s

Special K:

I appreciate your input a lot. I like the idea of buying the parts now and maintaining the rear end a lot. Some quick question for you:

-What is your current set up and how is your mpg? (engine, trans, rear)

This will be my dd and am looking for 15+ mpg when all is said and done.

Longhorn 70 · 11-14-2013, 11:05 AM

The rear end shouldn't change that much regarding MPG. It is the gearing that would make a difference. You CAN get more gear ratios with the 14BFF. IF the gearing you have now works for you keep driving it. If you need to get the rear changed in the future, the 14BFFs will still be out there.

As I stated before, I have 450K+ miles on mine. No noise, no clunks, no whine or real leaks. I'd trust mine for a daily driver. There are a BUNCH of Eatons on the road.

**special-K** · 11-14-2013, 11:15 AM

No matter what rear you have,it's the gear ratio that effects fuel mileage. My current truck is a K2500 with Dana60 4.10 posi and it gets 12.5 mpg with 350/TH350 and I haven't touched the carb in 10 years. My plans are to swap-in an HO52/No-Spin. For even better mileage I suggest O/D. I could do things under the hood to achieve better mileage,but this truck isn't for daily use. Plans are for a Dana60 front axle,37" tall tires,383/TH400.I'm going for tough and strong on this one. I actually gave the 4L80E/NP241 RH drop w/stand-alone ECM to a friend who has done me a lot of favors. I'm happy with 60-65 on the hiway and all O/D does for most people is allow them to drive faster and use the same amount of full as if they drove a more reasonable speed. When I drive my '92 with 4.10s and O/D @65mph I get 2-3 mpg better than doing 70-75.

Jahloha · 11-14-2013, 11:22 AM

Quote:

Originally Posted by Longhorn 70

The rear end shouldn't change that much regarding MPG. It is the gearing that would make a difference. You CAN get more gear ratios with the 14BFF. IF the gearing you have now works for you keep driving it. If you need to get the rear changed in the future, the 14BFFs will still be out there.

As I stated before, I have 450K+ miles on mine. No noise, no clunks, no whine or real leaks. I'd trust mine for a daily driver. There are a BUNCH of Eatons on the road.

Great insight. I have read how to verify my gearing, but need to do that. Plan on doing that this weekend after the bed is pulled. Did you ever end up doing the rear disc brakes? I saw you following a thread on the BlackBird disc kits...

Quote:

Originally Posted by special-K

No matter what rear you have,it's the gear ratio that effects fuel mileage. My current truck is a K2500 with Dana60 4.10 posi and it gets 12.5 mpg with 350/TH350 and I haven't touched the carb in 10 years. My plans are to swap-in an HO52/No-Spin. For even better mileage I suggest O/D. I could do things under the hood to achieve better mileage,but this truck isn't for daily use. Plans are for a Dana60 front axle,37" tall tires,383/TH400.I'm going for tough and strong on this one. I actually gave the 4L80E/NP241 RH drop w/stand-alone ECM to a friend who has done me a lot of favors. I'm happy with 60-65 on the hiway and all O/D does for most people is allow them to drive faster and use the same amount of full as if they drove a more reasonable speed. When I drive my '92 with 4.10s and O/D @65mph I get 2-3 mpg better than doing 70-75.

Makes a lot of sense. I do tend to drive closer to 70 then 60, so the O/D seems to make sense. I also use this daily and sometimes make 80 mile round trips, but usually 20-30 miles.

Also, I have read threads on how certain tires heights should be used with certain gears. Are you familiar with any posts that dive into that topic?

Longhorn 70 · 11-14-2013, 11:48 AM

Quote:

Great insight. I have read how to verify my gearing, but need to do that. Plan on doing that this weekend after the bed is pulled. Did you ever end up doing the rear disc brakes? I saw you following a thread on the BlackBird disc kits...

I haven't yet. I have to get approval from the CFO. She is a tough one. MAYBE I should put it on my Christmas wish list.

Jahloha · 11-14-2013, 12:02 PM

Quote:

Originally Posted by Longhorn 70

I haven't yet. I have to get approval from the CFO. She is a tough one. MAYBE I should put it on my Christmas wish list.

Haha, I totally understand. I am compiling a mass budget for this build, its always fun to run numbers, but sad to realize the actual costs.

I am trying to find the thread you started, or at least I think you did, on your front disc install. Do you have that link available? Or am I mistaken.

Longhorn 70 · 11-14-2013, 12:28 PM

Quote:

Originally Posted by Jahloha

...I am trying to find the thread you started, or at least I think you did, on your front disc install. Do you have that link available? Or am I mistaken.

Is this the thread you mean? It's the only one I can think of. It is more the outline of what I ran into while installing the front disc kit.

Jahloha · 11-14-2013, 12:32 PM

Quote:

Originally Posted by Longhorn 70

Is this the thread you mean? It's the only one I can think of. It is more the outline of what I ran into while installing the front disc kit.

Bingo. Thanks.

swamp rat · 11-14-2013, 09:35 PM

c20pickup · 11-14-2013, 09:41 PM

Quote:

Originally Posted by Longhorn 70

I haven't yet. I have to get approval from the CFO. She is a tough one. MAYBE I should put it on my Christmas wish list.

ill look forward to a thread when it is approved!

Jahloha · 11-15-2013, 12:18 AM

Quote:

Originally Posted by swamp rat

Holy cow! Awesome bro. Looks like I got some midnight reading to do. Im pumped

**special-K** · 11-15-2013, 09:01 AM

I've driven from Maryland to the Grand Canyon and back on a '71 Custom Camper/20 with camper @75 mph out & back with 4.10 rear and never missed a lick. These trucks can roll all day with the rest w/o overdrive. But,if fuel consumption is a concern,slower is better...with or w/o it.

Jahloha · 11-15-2013, 01:41 PM

Quote:

Originally Posted by special-K

I've driven from Maryland to the Grand Canyon and back on a '71 Custom Camper/20 with camper @75 mph out & back with 4.10 rear and never missed a lick. These trucks can roll all day with the rest w/o overdrive. But,if fuel consumption is a concern,slower is better...with or w/o it.

Yeah Special K I totally know what you mean. So would throwing in a 700r4 been change anything? Or does it all come down to the gear ration I'm running in back (I've yet to figure out what my ratio is)?

I respect your insight, so thanks for sharing your thoughts.

Longhorn 70 · 11-15-2013, 02:45 PM

Jaloha, first let me say and I think I speak for others on the board, we appreciate the respect you give to other's opinions.

Second, a 700R4 will make the engine turn fewer RPM for a given speed over 45MPH.
Third, 700R4s have a lower first gear that gets you out of the hole with less engine effort.
Fourth, the 700R4 in my beast allows me to get better mileage on sustained cruises. I choose whether or not to get that better mileage by how hard I push the pedal.

Now the bad news: Price, Strength as compared to TH400s, some don't like the low first gear, modifications needed, are factors that need to be considered.

Personally I like the lower first gear with the low geared rear end in my truck and the overdrive helps too. It cost me $1200 in 97 to get a 700R4 built and installed and I did the installing. Was it worth the extra 4 MPG hiway?? Over the 6 years of savings, yes especially because I was replacing a broken TH400. If the 400 weren't broken.....I dunno'.

OldCreek · 11-15-2013, 05:03 PM

If it ain't broke, don't fix it.

Most all wear parts can still be had from my experience.

Jahloha · 11-15-2013, 05:24 PM

Quote:

Originally Posted by Longhorn 70

Jaloha, first let me say and I think I speak for others on the board, we appreciate the respect you give to other's opinions.

Second, a 700R4 will make the engine turn fewer RPM for a given speed over 45MPH.
Third, 700R4s have a lower first gear that gets you out of the hole with less engine effort.
Fourth, the 700R4 in my beast allows me to get better mileage on sustained cruises. I choose whether or not to get that better mileage by how hard I push the pedal.

Now the bad news: Price, Strength as compared to TH400s, some don't like the low first gear, modifications needed, are factors that need to be considered.

Personally I like the lower first gear with the low geared rear end in my truck and the overdrive helps too. It cost me $1200 in 97 to get a 700R4 built and installed and I did the installing. Was it worth the extra 4 MPG hiway?? Over the 6 years of savings, yes especially because I was replacing a broken TH400. If the 400 weren't broken.....I dunno'.

Longhorn:

This is a great way to describe and compare these transmissions. I almost exclusively do highway driving, at least I am over 45 all the time haha. So that does attract me. I also look at the fact that if I am going to rebuild the trans anyways, I might as well drop a couple hundred more and get the 700r4 in. I am in with you, if this is my DD, and I am putting 10-15k miles a year on it, better make the swap now.

11-13-2013, 01:11 PM	#1
Jahloha Registered User Join Date: Oct 2013 Location: Anaheim, CA Posts: 526	Keep or Replace Eaton Rear End I have a 1970 C20 with an Eaton rear end. I read everywhere on this site that the Eaton is a rock and if kept taken care of, will last forever. But I also read that parts for this rearend are very rare to find and purchase. So being untaught, what parts are hard to find? I hoping to do a disc swap on both the front and back...would this resolve the difficulty of finding these parts? Thanks for the insight. __________________ -JASON My grandpa, Gramps, won a 1970 C20 in 1969 for $1. I'm on a mission to restore it before he passes. My 1970 C20 Build Thread

11-13-2013, 03:34 PM	#2
c20pickup Registered User Join Date: Apr 2013 Location: Brighton, WI Posts: 504	Re: Keep or Replace Eaton Rear End the eaton is a tank, there are a few nice things about it, removable third member and also the rigidity of it. but that's about where the pros end. the hard parts to find for it, are basically everything, seals, bearings, brake parts, gear sets, hubs, lockers, etc. people have adapted the eaton to use 14 bolt backing plates and then Cadillac calipers to convert to discs brakes. also the option of lockers is also limited, seems as if you can find a factory "no-spin" lockers (very rare, and frankly overpriced for a used locker, ive looked into it) or you can use a locker out of a 14 bolt, but then you have to use 14 bolt axle shafts and shave them down 1/4 inch to accept the third member. in my opinion I would replace he axle with a dana 60 or a 14bolt, just for the fact that when it needs to be serviced, its not a hodge podge of parts all stuck together that needs to be custom made. and at what point, after changing all the internals and brake parts does a eaton remain an eaton? and at what point would it be easier to swap in something that already has discs and a locker. im open to questions, been doing a lot of researched on these axles lately. good luck!

11-13-2013, 08:30 PM	#3
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Re: Keep or Replace Eaton Rear End Bearings, brake parts, hubs, pinion supports and so on are kinda hard to find and pricey when you do. If it isn't a show truck, drive the Eaton until it breaks, if it ever does. THEN 14 bolt FFs are easy to find reasonable. Easy to change and adapt. Another big plus to the 14BFFs is there are more gear ratios available. If it is a showgo, then get the prettiest and bolt it up. My HO52 has over 450K miles on it and all I have really done is keep it lubed and seal leaks. I have POUNDED that thing with torque and carried, not many, heavy loads from time to time. It has also been when I was young and dumb, used at high speeds. It isn't pretty but it works. __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9

11-13-2013, 10:28 PM	#5
swamp rat Registered User Join Date: Oct 2007 Location: Spanaway Posts: 8,451	Re: Keep or Replace Eaton Rear End You can get all the bearings, seals and even the felt pinion seal for the diff thru Randys Ring and Pinion in Seattle, That includes the big pinion bearing but it is expensive. Wheel hub bearings and seals can be bought at the auto parts store, the only replacements are tapered roller bearings instead if the Barrel bearings. Brake parts can be found but don't all come easy, the shoes can be relined if necessary, i think even the drums can still be found. You can use a conversion bracket for a 14 bolt disk conversion on the Eaton, some places market one for the Eaton too. Front rotors and calipers from a 72 4X4 will work on the rear, so it should be the same on a C20, just know there are light duty and heavy duty rotors and calipers, you do want the heavy duty stuff, 1" thick rotors are light duty, 1 1/4" thick rotors are heavy duty. __________________ Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's

11-14-2013, 08:54 AM	#6
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Keep or Replace Eaton Rear End Do what those of us who have driven older vehicles daily have always done...get the parts now while you can and have them ready for the day you might possibly need them. If not,years down the road you'll have parts no one else can get to sell when you move on. Or,you could buy the parts,install them,whether they need it or not,and be good to go. Parts may be higher on these,but they aren't cheap on a 14-bolt and,unless someone gives you one already altered to go under a 67-72,you're looking at some expense there. If you do discs,your only concern is wheel bearings. Even if those go extinct from parts stores,I've found you can usually find bearing by dimension from a bearing distributor. Also,14-bolt brakes can be fitted up to an HO52 Corporate rear. Or,you could just run it,maintain it,and not worry about the rare chance a problem will occur. These rears are under GM Trucks dating back into the '40s __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~ Last edited by special-K; 11-14-2013 at 09:28 AM.

11-14-2013, 11:05 AM	#8
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Re: Keep or Replace Eaton Rear End The rear end shouldn't change that much regarding MPG. It is the gearing that would make a difference. You CAN get more gear ratios with the 14BFF. IF the gearing you have now works for you keep driving it. If you need to get the rear changed in the future, the 14BFFs will still be out there. As I stated before, I have 450K+ miles on mine. No noise, no clunks, no whine or real leaks. I'd trust mine for a daily driver. There are a BUNCH of Eatons on the road. __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9

11-14-2013, 11:15 AM	#9
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Keep or Replace Eaton Rear End No matter what rear you have,it's the gear ratio that effects fuel mileage. My current truck is a K2500 with Dana60 4.10 posi and it gets 12.5 mpg with 350/TH350 and I haven't touched the carb in 10 years. My plans are to swap-in an HO52/No-Spin. For even better mileage I suggest O/D. I could do things under the hood to achieve better mileage,but this truck isn't for daily use. Plans are for a Dana60 front axle,37" tall tires,383/TH400.I'm going for tough and strong on this one. I actually gave the 4L80E/NP241 RH drop w/stand-alone ECM to a friend who has done me a lot of favors. I'm happy with 60-65 on the hiway and all O/D does for most people is allow them to drive faster and use the same amount of full as if they drove a more reasonable speed. When I drive my '92 with 4.10s and O/D @65mph I get 2-3 mpg better than doing 70-75. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

11-14-2013, 09:35 PM	#15
swamp rat Registered User Join Date: Oct 2007 Location: Spanaway Posts: 8,451	Re: Keep or Replace Eaton Rear End If you guys are interested here's all the Threads i saved with pertinent info on the Eaton, this includes both drum brakes as well as some disk conversions info.. http://67-72chevytrucks.com/vboard/s...d.php?t=595571 http://67-72chevytrucks.com/vboard/s...d.php?t=200268 http://67-72chevytrucks.com/vboard/s...d.php?t=590959 http://67-72chevytrucks.com/vboard/s...d.php?t=593259 http://67-72chevytrucks.com/vboard/s...d.php?t=540983 http://67-72chevytrucks.com/vboard/s...d.php?t=475710 http://67-72chevytrucks.com/vboard/s...d.php?t=401974 http://67-72chevytrucks.com/vboard/s...d.php?t=183452 http://67-72chevytrucks.com/vboard/s...d.php?t=408600 http://67-72chevytrucks.com/vboard/s...d.php?t=401745 http://67-72chevytrucks.com/vboard/s...d.php?t=399201 http://67-72chevytrucks.com/vboard/s...d.php?t=391609 http://67-72chevytrucks.com/vboard/s...d.php?t=172827 __________________ Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's

11-15-2013, 09:01 AM	#18
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,851	Re: Keep or Replace Eaton Rear End I've driven from Maryland to the Grand Canyon and back on a '71 Custom Camper/20 with camper @75 mph out & back with 4.10 rear and never missed a lick. These trucks can roll all day with the rest w/o overdrive. But,if fuel consumption is a concern,slower is better...with or w/o it. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

11-15-2013, 02:45 PM	#20
Longhorn 70 Registered User Join Date: Dec 2012 Location: Chandler AZ Posts: 1,149	Re: Keep or Replace Eaton Rear End Jaloha, first let me say and I think I speak for others on the board, we appreciate the respect you give to other's opinions. Second, a 700R4 will make the engine turn fewer RPM for a given speed over 45MPH. Third, 700R4s have a lower first gear that gets you out of the hole with less engine effort. Fourth, the 700R4 in my beast allows me to get better mileage on sustained cruises. I choose whether or not to get that better mileage by how hard I push the pedal. Now the bad news: Price, Strength as compared to TH400s, some don't like the low first gear, modifications needed, are factors that need to be considered. Personally I like the lower first gear with the low geared rear end in my truck and the overdrive helps too. It cost me $1200 in 97 to get a 700R4 built and installed and I did the installing. Was it worth the extra 4 MPG hiway?? Over the 6 years of savings, yes especially because I was replacing a broken TH400. If the 400 weren't broken.....I dunno'. __________________ 1970 Longhorn, Front Disc, 350/4 bolt, 882 heads, HEI, Edelbrock, 700R4, HO-52/4.11. 1996 Corvette, Collector Roadster, LT4, 396, 450RWHP, 6sp, 4.11/Dana44/posi 5 point roll bar And let us not grow weary of doing good, for in due season we will reap, if we do not give up. Gal 6:9

11-15-2013, 05:03 PM	#21
OldCreek Registered User Join Date: Jan 2007 Location: Central Coast California Posts: 1,026	Re: Keep or Replace Eaton Rear End If it ain't broke, don't fix it. Most all wear parts can still be had from my experience. __________________ 1972 K20 Suburban 5.7/700r4/NP205 Dana 44/H052 Sold 1972 C10 5.3L/4L60E 12bolt 5Lug - Sold 1971 K5 Blazer 6.0L LQ9 4L60E NP205 Dana 44/H052!!! 1970 K3500 1ton CrewCab 8.1L/Allison1000/NP205 Dana 60/14B!!!! - Sold 1984 K10 SWB 7.4L/4L80e/NP208 Corp 10/12 bolt Sold 1988 V30 CCLB 7.4L/TH400/NP205/Dana 60/Dana 70/3.73!!! (Sold) 2003 K2500HD 8.1/Allison1000/NP263

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