Easy Rear End Swap ?? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Jim Molloy · 11-12-2003, 01:46 PM

Is there such a thing.

My stepside is screaming at 6OMPH. I'd like some better highway
gears.Like at least a 3.00 or even 2.75's.

I know I know with my 6 popper it will be gutless,its gutless
now. LOL.

Since future plans call for a V-8 this could be the first step.

Is there a car ? or truck rearend assembly that would fit ?
Something that would have highway gears or parts could be
had cheaply ?(Used ?)
Same side to side width ,same 5 lug wheel pattern ?

Am I dreaming ?

I would have the rear end installed on top of the springs for
the lowering factor.Are flip kits nessesary or can a good welder
make it work from the parts already on the rear axle ?

By flipping the axle would I need a C-notch ? Again could a good
welder make one up ?

Would I need shorter shocks ?

Any thoughts or ideas welcomed .

Jonboy · 11-12-2003, 01:54 PM

I would look for an axle out of a newer truck. Some had 3.08's and even 2.73's I believe. That will bolt right in.

Since I can't weld, I am not sure about using existing parts for the flip kit. I don't think they are too expensive, but you will want to do the front at the same time, as it will drop the rear about 5-6".

*Zilverado* · 11-12-2003, 03:24 PM

Jim,

When I swapped the rearend on my '86, I took the entire assembly (leaf springs and all) out in one piece - it had a 10 bolt differential with 3.08 gears. Replaced the assembly with the heavier sprung rearend from my '77 doner truck - it had a 12 bolt diff with 3.07 gears.

The only thing I had to do was move the rear spring hangers back and bolt 'er all together. Oh, I also needed a cross-over u-joint to mate the older pinion yoke to the new drive shaft.

So, I would say "yah" that should be doable. Parts should be out there...

BTW - - With my 305 and OD tranny, I like the 3.07's. Might not have the jam, but the 22+ mpg (depending on the conditions) on hwy is great.

As far as the flip kit is concerned, I like my trucks at stock height or higher - so I wouldn't know too much about that.

Have fun.

r0lf- · 11-12-2003, 04:53 PM

Im guessing you have 3.73's in yours like I have in my 80. yeah... those suckers like to eat gas on the freeway. But once my brother does the bigblock swap in it, it is gonna fly with those 3.73's.

**Captkaos** · 11-12-2003, 04:58 PM

Any truck rearend from 73-87 will go under it and bolt in. The issues you need to look for is the heavy duty rear suspension. If you just want to swap rearends though, you can get any of them to work, and just changed the brakes out. Typically 3.08 gears were common on the 73-81's with the 12 bolt like you have. BTW, I would stick with the 12bolt, you won't need the hybrid (high dollar) u-joint if you do.

ElGracho · 11-12-2003, 07:05 PM

Jim,

Are you going to the swap meet this weekend? I'll be down there with my uncle. We'll probably be in his red 86 LWB.

Jim Molloy · 11-12-2003, 09:22 PM

Thanks for all the help folks.

Now need to find that high-ballen rear end so I can go fast !!

Anyone have one close to me ??

Anyone know what a complete rear end hub to hub not including
springs would be worth ? Used of course and 5 lug half ton.
With 3.0 or so gearing.Posi maybe.

Swap meet in Albany this weekend .Yes I'll be there.

Friend of mine at work and a couple of other quys are sellin stuff.

I have an old Tote Gote ,models ,some VW parts and other junk.

Also there will be some Honda mini-bikes ,CB450 and other
assorted stuff .Come on by we'll be in the dirt floor room down
at the south end by the stairs.

Tall ,glasses ,goatee ,baseball hat.That's me.

**crossy** · 11-12-2003, 11:11 PM

Jim, if you have to pay over $100 for an open ended 2.73 I'll be surprised, may even find a 3.08. the axle code is stamped on the top of the passenger side axle tube. there are lierally hundreds of these 3 letter codes,but I have most of em, I could find what gears arein yours or tell you what you found. Is yours a 10 or 12 bolt?? they started putting 10 bolts in 0n light duty applications. like yours, as early as 78. Use a file and find that 3 letter code ,prolly starts with a 'T' or 'K' . DAVE

soleeagle · 11-13-2003, 12:41 AM

My 80 4x4 has 2.73 gears in a 12 bolt. Bad thing is some jack @$$ that had it before me put 33 inch tires on it and I almost have to wind it up to get it moving. One of these days I am planning on getting smaller tires to put on it or maybe even get a axel with 3.08 gears like my 85 has. They are out there you just have to look since they werent very common in the trucks.

bpmcgee · 11-13-2003, 01:09 AM

Why wouldn't you just switch to better gears in the same pumpkin? Seems like a bit of a hassle to have to swap a whole axle doesn't it?

Brian

soleeagle · 11-13-2003, 01:19 AM

The axle would be alot cheeper and eisier to do. If you dont get the gears set up right they will whine and not last.

11-12-2003, 01:46 PM	#1
Jim Molloy Registered User Join Date: Dec 1999 Location: Albany,OR Posts: 49	Easy Rear End Swap ?? Is there such a thing. My stepside is screaming at 6OMPH. I'd like some better highway gears.Like at least a 3.00 or even 2.75's. I know I know with my 6 popper it will be gutless,its gutless now. LOL. Since future plans call for a V-8 this could be the first step. Is there a car ? or truck rearend assembly that would fit ? Something that would have highway gears or parts could be had cheaply ?(Used ?) Same side to side width ,same 5 lug wheel pattern ? Am I dreaming ? I would have the rear end installed on top of the springs for the lowering factor.Are flip kits nessesary or can a good welder make it work from the parts already on the rear axle ? By flipping the axle would I need a C-notch ? Again could a good welder make one up ? Would I need shorter shocks ? Any thoughts or ideas welcomed . __________________ 1979 Chevy Stepside 250-6,auto. 1981 Suzuki 850 70's Chopper,Springer,hardtail,750 Suzuki engine '84 Stang-wife's

11-12-2003, 01:54 PM	#2
Jonboy Slots go on anything! Join Date: May 2003 Location: Richardson, TX Posts: 5,957	I would look for an axle out of a newer truck. Some had 3.08's and even 2.73's I believe. That will bolt right in. Since I can't weld, I am not sure about using existing parts for the flip kit. I don't think they are too expensive, but you will want to do the front at the same time, as it will drop the rear about 5-6". __________________ 1974 Jimmy- 5.3/4L80e/NP241

11-12-2003, 04:53 PM	#4
r0lf- Hotwheels? Join Date: Dec 2002 Location: Pleasant Hill, CA Posts: 1,145	Im guessing you have 3.73's in yours like I have in my 80. yeah... those suckers like to eat gas on the freeway. But once my brother does the bigblock swap in it, it is gonna fly with those 3.73's. __________________ 1978 Money Pit - CUSTOM DELUXE!!!!

11-12-2003, 04:58 PM	#5
Captkaos www.73-87chevytrucks.com Join Date: Dec 1999 Location: Birmingham, AL Posts: 6,935	Any truck rearend from 73-87 will go under it and bolt in. The issues you need to look for is the heavy duty rear suspension. If you just want to swap rearends though, you can get any of them to work, and just changed the brakes out. Typically 3.08 gears were common on the 73-81's with the 12 bolt like you have. BTW, I would stick with the 12bolt, you won't need the hybrid (high dollar) u-joint if you do. __________________ Chris Lucas 1973 Chevy C-10 1978 GMC Jimmy (2WD) - SOLD 1987 R10 twin turbo LS 1991 R3500 SRW CrewCab 1985 K5 diesel swapped project 1989 K5 2WD conversion w/ Vette susp Project Captkaos Customs 73-87chevytrucks.com

11-12-2003, 07:05 PM	#6
ElGracho Gentleman Jim Driver Join Date: Nov 2002 Location: Poulsbo, WA Posts: 1,550	Jim, Are you going to the swap meet this weekend? I'll be down there with my uncle. We'll probably be in his red 86 LWB. __________________ Joe '75 GMC Gentleman Jim '84 Chev C10 Short Wide - Super duper plain (manual steering, manual brakes, no dome light, no cig lighter) '85 Chev C10 Short Wide - Super plain Vortec 4.8 4L60E trans also: '81 K30, '83 C30 Crew Dually, '84 M1028 CUCV, '85 M1009 CUCV, another '85 C10 SWB, '89 R3500 Flatbed

11-12-2003, 03:24 PM	#3
Zilverado Account Suspended Join Date: Nov 2002 Location: Winnipeg, Manitoba, Canada Posts: 798	Jim, When I swapped the rearend on my '86, I took the entire assembly (leaf springs and all) out in one piece - it had a 10 bolt differential with 3.08 gears. Replaced the assembly with the heavier sprung rearend from my '77 doner truck - it had a 12 bolt diff with 3.07 gears. The only thing I had to do was move the rear spring hangers back and bolt 'er all together. Oh, I also needed a cross-over u-joint to mate the older pinion yoke to the new drive shaft. So, I would say "yah" that should be doable. Parts should be out there... BTW - - With my 305 and OD tranny, I like the 3.07's. Might not have the jam, but the 22+ mpg (depending on the conditions) on hwy is great. As far as the flip kit is concerned, I like my trucks at stock height or higher - so I wouldn't know too much about that. Have fun.

11-12-2003, 09:22 PM	#7
Jim Molloy Registered User Join Date: Dec 1999 Location: Albany,OR Posts: 49	Thanks for all the help folks. Now need to find that high-ballen rear end so I can go fast !! Anyone have one close to me ?? Anyone know what a complete rear end hub to hub not including springs would be worth ? Used of course and 5 lug half ton. With 3.0 or so gearing.Posi maybe. Swap meet in Albany this weekend .Yes I'll be there. Friend of mine at work and a couple of other quys are sellin stuff. I have an old Tote Gote ,models ,some VW parts and other junk. Also there will be some Honda mini-bikes ,CB450 and other assorted stuff .Come on by we'll be in the dirt floor room down at the south end by the stairs. Tall ,glasses ,goatee ,baseball hat.That's me. Last edited by Jim Molloy; 11-12-2003 at 09:24 PM.

11-12-2003, 11:11 PM	#8
crossy Oh,you can't buy that new Join Date: Apr 2000 Location: Pennsville,N.J. 08070, USA Posts: 2,039	Jim, if you have to pay over $100 for an open ended 2.73 I'll be surprised, may even find a 3.08. the axle code is stamped on the top of the passenger side axle tube. there are lierally hundreds of these 3 letter codes,but I have most of em, I could find what gears arein yours or tell you what you found. Is yours a 10 or 12 bolt?? they started putting 10 bolts in 0n light duty applications. like yours, as early as 78. Use a file and find that 3 letter code ,prolly starts with a 'T' or 'K' . DAVE __________________ "been there, done that, ruined the T-shirt". 2007 LBZ GMC Sierra, ECSB 2006 LM7 RCSB Silverado 98 Vortec project. 94,3500,6.5L 4L80 81 SWB GMC POS finally gone 73 Pinto, stock, w/CragarSS's-eww LOTS of Cummins trucks.

11-13-2003, 12:41 AM	#9
soleeagle Registered User Join Date: Sep 2003 Location: Shelbyville, Indiana Posts: 614	My 80 4x4 has 2.73 gears in a 12 bolt. Bad thing is some jack @$$ that had it before me put 33 inch tires on it and I almost have to wind it up to get it moving. One of these days I am planning on getting smaller tires to put on it or maybe even get a axel with 3.08 gears like my 85 has. They are out there you just have to look since they werent very common in the trucks. __________________ Chuck '85 Chevy Silverado 4X4 '91 Chevy 4X4 Suburban http://www.cardomain.com/memberpage/545941

11-13-2003, 01:09 AM	#10
bpmcgee Registered User Join Date: Mar 2003 Location: Northern Illinois Posts: 2,181	Why wouldn't you just switch to better gears in the same pumpkin? Seems like a bit of a hassle to have to swap a whole axle doesn't it? Brian

11-13-2003, 01:19 AM	#11
soleeagle Registered User Join Date: Sep 2003 Location: Shelbyville, Indiana Posts: 614	The axle would be alot cheeper and eisier to do. If you dont get the gears set up right they will whine and not last. __________________ Chuck '85 Chevy Silverado 4X4 '91 Chevy 4X4 Suburban http://www.cardomain.com/memberpage/545941



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