Rockhugger

Hello everyone!
This is my first post. I couldn't find an answer from searching, but I apologize if this has been answered before.

The rear end on my 1989 1500 4x4 reg cab short bed is dead. It's a GU6 option so it has 3.42 gears, 10 bolt.

What is the newest rear end that would be a good replacement?
All the old trucks have been crushed so I can't easily find one at a yard. I'd like to get something with fewer miles on it anyway. Maybe rear disk brakes?
Buying a rebuilt one is over a grand so there must be a better option.

Any advice?

Thanks,
Andy

14GMCZ71

Quoting info from posts I read years ago:

14bsf out of a similar gen 1500 heavy duty or 2500 light duty 2wd.

Direct swap aside from a conversion u-joint.

448 conversion U-Joint
moog is hmg448
precision is just 448

I read someone removed the pinion from the 10 bolt and installed in on the 14. No need for a conversion u-joint in that scenario.


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you need a precision u joint #447

this converts the 10b drive shaft to the 14b diff

abs will be fine with the larger drums

did the rear end come from a 4x4 because gm used 2 diff width rears in the trucks

~65 inch wms for 2wd and ~68 inch wms for 4x4's

the 14bsf came in 1500 with towing package and in ld 2500's (88-98 models)
in 1500hd's and 2500 ld's but only in 8lug in the 99+ models


9.5" 14 bolt is semi floating. It has c-clips. If the gears or axle breaks, the axle can go out the housing tubes.

10.5" 14 bolt is full floating. It is massive, and tires stay on the axle regardless of what happens internally.

14GMCZ71

More info:


To make a '99 (I think) or newer Eaton Posi work in an older truck (like my old '91 Z71) use the following bearings:

Timken Part Number: LM102949 - Cone
Timken Part Number: LM102911 - Race

Check out:

http://www.timken.com

Timken F.Y.I.:

LM501349 Cone - 1.6250 Bore
LM501314 Cup - 2.8910 OD
Bearing Width - 0.8437

LM603049 Cone - 1.7812 Bore
LM603012 Cup - 3.0625 OD
Bearing Width - 0.8437

LM102949 Cone - 1.7812 Bore
LM102911 Cup - 2.8910 OD
Bearing Width - 0.8437

I needed LM102949 & LM102911 to make a later model Eaton Posi (10-bolt - 8.5 inch - 30-spline) work in my '91 Chevy Z71.

Rockhugger

Hi 14GMCZ71,

Thanks for posting some information. I'm not sure what it all means. I'll have to forward it to my buddy who is supposed to be working on finding me a rear end.

Yes, the rear end is still in the 4x4. As far as I know it's the original. So it must be the 68" width.

I don't need anything fancy or upgraded. I just want a working 4x4.
Obviously, this is not straight forward. Maybe I should just pay a shop to rebuild it. Hmmm.

Thanks,
Andy