Rear End ???

[84slopwaggin]

Well it looks like I'll have to have the rear end rebuilt in my 85 2wd. As long as it's opened up I was thinking of going with 3.42 gears. I'm wondering if it's a big difference between 3.42 and 3.08 gear ratios? Do our trucks come stock with Limited Slip Differentials? The truck will be used for a daily driver. It has a stock 350 tranny. They're charging $970.00. I'll find out this morning what all that includes. What are your opinions on installing 3.42's vs. 3.08's? What suggestions do you have for the limited slip differentials?

[greg0380]

maybe my experiences can guide you. I have an 85 2WD, 27.5 inch tall tires. The truck was stock with 2.73s. I got a cheap 3.08 complete rear axle and swapped it in. Not a big difference between the two ratios. I still wasn't happy.

So i took my original 2.73 rear axle and rebuilt it with new bearing and seals and bought a ring and pinion from Richmond gear and went with the 3.42s. I had them installed for $125 at a local machine shop. I am happy with that ratio. I have a 5 speed manual trans. In 4th gear (1:1) I can do 65 and turn around 2200-2300 Rpms (according to my tach). I really don't use 5th till I'm over 60 - 65 mphs.

My suggestion would be to go with the 3.42s, but it really depends on what size tire you are running too. Good luck.

[N2TRUX]

Originally Posted by 84slopwaggin

Well it looks like I'll have to have the rear end rebuilt .... They're charging $970.00. I'll find out this morning what all that includes....

That should include a kiss. Unless you destroyed the carrier and axles that seem rather high.

Many of these trucks came with an optional locking rear end, but it was not "stock". I think you will appreciate the additional low end torque generated by a 3.42 gear. Your highway mileage will decrease about 1 mpg . If you do a lot of local driving it might improve so it's not a bad trade off.

[84slopwaggin]

Well eventually I want to run 275/60/15 tires.

[piecesparts]

That price ofr the changeout of your rear end is about what it is around here. kiss or not that is what the shops want. You can run the 3.42 or a 3.73 geared rear end with the 275/60 tires and get decent mileage, along with the better acceleration. Since you have a TH350, I would not go any lower than the 3.42 gears.

[84slopwaggin]

Yeah it's $412.00 for labor. The spider gears and ring n pinion were wore pretty bad. It's also getting axle bearings replaced. I just went with a eaton limited slip unit and 3.42's. I'm embarrassed to say what it's costing now and angry for not having the knowledge to do it myself . I need to join a 73-87 CHEVY/GMC TRUCK support group right about now. I'm really disappointed in myself for not taking the time to plan this rear end repair/replacement better .

[Srubydo1986]

i feel for yea i blew the rear out of my truck so i went looking for a new one found a truck and been carless for 4 week now i think

[bulky]

Originally Posted by 84slopwaggin

Yeah it's $412.00 for labor. The spider gears and ring n pinion were wore pretty bad. It's also getting axle bearings replaced. I just went with a eaton limited slip unit and 3.42's. I'm embarrassed to say what it's costing now and angry for not having the knowledge to do it myself . I need to join a 73-87 CHEVY/GMC TRUCK support group right about now. I'm really disappointed in myself for not taking the time to plan this rear end repair/replacement better .

Replacing the nest & gearset is not a nut and bolt quickie. You do need to know what you are doing. Dont be embarrased abotu not being able to do it yourself. It takes alot of experience to set up a rear end correctly. It is a time consuming process of shimming and measuring to get the right pattern so it wont bind up or whine on the highway. Shop labor up here at a decent shop is around $85 an hour. $412 is not that far off, dont worry about it. You will have a nice rear end (no jokes about that comment) when it is done.

[84slopwaggin]

Well I told the service attendent that I wanted to do it right for the last time as I took a really deep breath. We'll see

[piecesparts]

Originally Posted by bulky

Replacing the nest & gearset is not a nut and bolt quickie. You do need to know what you are doing. Dont be embarrased abotu not being able to do it yourself. It takes alot of experience to set up a rear end correctly. It is a time consuming process of shimming and measuring to get the right pattern so it wont bind up or whine on the highway. Shop labor up here at a decent shop is around $85 an hour. $412 is not that far off, dont worry about it. You will have a nice rear end (no jokes about that comment) when it is done.

I agree, there is a process to setting up a rear end properly. There are alot of "Wrenchers" out there that will tell you the rights and wrongs to the whole process, BUT, they can probably learn a thing or two. I have done it in the past, but when it came to my last couple of rear ends, I gave it to someone else that had the time and parts on the bench to do it in a short order. Never be embarrassed, unless yo drop your shorts at a wedding.

[Pyrotechnic]

Depends on your application and transmission. I ran a 3.08 with some slightly lower profile tires than stock and it worked out to where 75MPH was about 3000RPM, this is with a turbo 350 and a 2500 stall converter.

[84slopwaggin]

Hey I really appreciate the support guys. It will see limited use until I get the wheels and tires 15x8,275/60/15.

[hiway]

You will love that ratio. Who's doing the work?

[Gary]

Originally Posted by 84slopwaggin

Hey I really appreciate the support guys. It will see limited use until I get the wheels and tires 15x8,275/60/15.

This sounds very familiar. I just got my truck back 2 days ago.

It had factory(?) 2.73 10 bolt rear. I had them put in an Eaton posi and 3.73 gears (basically all new rearend) and he replaced the rearend seals too. Also while they had it they pulled the oil pan and pulled out the broken off tip of my dipstick (DOH!) and I also had them replace the single plane intake with a new Crosswind dual plane intake so the little Edelbrock won't be so unhappy). They also adjusted the springs a bit in the HEI to make it a little less radical and fixed a small oil drip. My total bill was $1400 and that included the new intake, the new gears, the posi, everything.

I'm also running 275/60-15 tires but on 15x10 wheels though.

[boatpuller]

Originally Posted by Dixiesys

This sounds very familiar. I just got my truck back 2 days ago.

It had factory(?) 2.73 10 bolt rear. I had them put in an Eaton posi and 3.73 gears (basically all new rearend) and he replaced the rearend seals too. Also while they had it they pulled the oil pan and pulled out the broken off tip of my dipstick (DOH!) and I also had them replace the single plane intake with a new Crosswind dual plane intake so the little Edelbrock won't be so unhappy). They also adjusted the springs a bit in the HEI to make it a little less radical and fixed a small oil drip. My total bill was $1400 and that included the new intake, the new gears, the posi, everything.

I'm also running 275/60-15 tires but on 15x10 wheels though.

how did it feel? i'm in the thinking stages of doimg something back there.i've got stock 12 bolt,3.08 rear.with my near 29 inch tires,i'm wanting a lower ratio.i would like to end up in the 3.50 ratio area with my tire size i think a 3.73 would work.but,i'm not sure if the th 350 is real compatiable with that ratio?

[Gary]

Well I'm running a 700r4 with a pretty healthy heaping of horsepower and it feels almost scary. It chirps 2nd gear a lot even with the 2800 stall converter. With the 4th gear though highway speeds are no problem.

[84slopwaggin]

Originally Posted by hiway

You will love that ratio. Who's doing the work?

Superior Springs Clutch & Gear is doing the work. It's a reliable company in North Little Rock. They do alot of big rigs, city vehicles, etc. They have did U joint jobs for me in the past.

[84slopwaggin]

Originally Posted by Dixiesys

This sounds very familiar. I just got my truck back 2 days ago.

It had factory(?) 2.73 10 bolt rear. I had them put in an Eaton posi and 3.73 gears (basically all new rearend) and he replaced the rearend seals too. Also while they had it they pulled the oil pan and pulled out the broken off tip of my dipstick (DOH!) and I also had them replace the single plane intake with a new Crosswind dual plane intake so the little Edelbrock won't be so unhappy). They also adjusted the springs a bit in the HEI to make it a little less radical and fixed a small oil drip. My total bill was $1400 and that included the new intake, the new gears, the posi, everything.

I'm also running 275/60-15 tires but on 15x10 wheels though.

I wasn't aware you could run 15x10 wheels with 275/60/15 tires. I think I might like that look a little better. I love the way your truck sets. You definitely got a really good package deal.

[pcmcobra]

this is so weird, just last night I was looking at rear gears...
got a stock 10 bolt w/ 2.73 th350.
Was thinking of getting it changed. Several years ago when I had a 71 c10, I took it to a shop to see about getting the gears changed..quote was around $1000...I declined...and sold the beast.
So you guys are saying the 3.42 would be better for the th350
don't mean to hijack your thread 84...

[hiway]

275/60 on a 10" looks fine. Do 235/60 on the front to match.
I've had good luck with Superior. Thought maybe you were going to Mud Connection. Monroe's in Greenbrier charges $300 for a simple gear install. So Superior is right on par with your rear rebuild and setup.

[alec22]

For $970 you get a...forget it, that's not appropriate on this forum!!

I've built about a dozen axles for Jeeps which include dana 60's, dana 44's, amc 20's, and 14 bolts. When I took my first housing into a drivetrain shop and they quoted me over $300, and I had all the parts, I decided to learn all about it. For what it costs to have an axle setup, you can buy all the tools to you need to do the job plus a case of your favorite bEvERage and pizza for all your friends.

Check out www.drivetraindirect.com under their ring & pinion section they have exceptional directions about setting up a rear end.

Honestly, people talk about it being hard but it's really not. I think this is more fear of the unknown then anything. Also, most times than not, you won't need to add or remove shims.

[84slopwaggin]

Originally Posted by alec22

For $970 you get a...forget it, that's not appropriate on this forum!!

I've built about a dozen axles for Jeeps which include dana 60's, dana 44's, amc 20's, and 14 bolts. When I took my first housing into a drivetrain shop and they quoted me over $300, and I had all the parts, I decided to learn all about it. For what it costs to have an axle setup, you can buy all the tools to you need to do the job plus a case of your favorite bEvERage and pizza for all your friends.

Check out www.drivetraindirect.com under their ring & pinion section they have exceptional directions about setting up a rear end.

Honestly, people talk about it being hard but it's really not. I think this is more fear of the unknown then anything. Also, most times than not, you won't need to add or remove shims.

Hey alec22 I wish I had your knowledge and drive. I have very little wrenching ability, so this is the route I had to take. Just thinking about the setup I would have thought with the new components being installed it would be a need to add or remove shims. Your right about fear. I would love one day to lower one of my trucks, but I have no knowledge of swapping spindles. Maybe one day with research and careful planning I'll complete the job.

[84slopwaggin]

Originally Posted by hiway

275/60 on a 10" looks fine. Do 235/60 on the front to match.
I've had good luck with Superior. Thought maybe you were going to Mud Connection. Monroe's in Greenbrier charges $300 for a simple gear install. So Superior is right on par with your rear rebuild and setup.

I always thought that it wasn't possible to mount a 275 tire on a 10 inch rim. I see wheels listed in Jegs and Summit and they always list 8 inches in the 275 specs. The thing with the staggered fit is you can't rotate the tires. I'm still trying to decide on that. If the 10 inch rim is gonna put too much stress on the front suspension I'll just go 8, but I really love the way Dixiesys truck sits. I believe his is lowerd, but how low front/rear.

[84slopwaggin]

It's done. $866 parts, $402.5 labor, $114 sales tax= ouch. Eaton Posi unit, 3.42gears, new axle bearings/seals, new Ujoint, 3qt.synt gear oil, posi additive. Now I've got a question about the speedometer. It feels like it's off. It feels like I'm traveling slower than the speedometer is actually reading. Would this be because it gets upto speed sooner or what?

[hiway]

Yep...your speedo gears now don't match. What trans do you have? Most dealership parts counters(good ones anyway) have a chart to tell what speedo gears you need. They are like $10 each or something. You may just change the pinion or both ring/pinion. Pinion is easy and on the side of the trans. Ring means pullin the driveshaft and tail shaft to slide it off your output shaft. How does she feel with the new rear...snappy?