2003 rear end swap?

**bone stock** · 03-11-2008, 06:56 PM

I have a gt4 with g80 and I'm told the spider gear is broke making noise when turning. The mech. said he didn't know what else was damaged so he told me to find a used rear end. sounds nuts to me but...

will a two wheel drive fit ok on the truck with the same 3.73s? If so what years fit my 03?

I ask because the price is cheaper and if I can avoid a gov bomb I will.

**unplugged** · 03-11-2008, 09:20 PM

Wrecking yards have access to interchange manuals like Hollander's. They can tell you what will fit and what mods if any.

**MrShorty** · 03-12-2008, 12:26 AM

Did he open it and verify that it's just the spider gears that are bad? I could be wrong, but I don't know that it's that expensive just to replace the spider gears. Where it starts to get expensive is when you have to replace the carrier and/or ring and pinion. I think the first thing I would do would be to determine exactly what needs to be replaced.

FWIW, it might make a difference if you have a 10 bolt or a 14 bolt rear. What are you driving? 1500 or 2500 or bigger? 6 lug or 8 lug? Do you want to come out as cheap as possible or do you want to take this opportunity to upgrade (from a 10 bolt to 14 bolt or from a G80 to a different locker/LS, for example)? Do you have disc or drum brakes?

**bostic8** · 03-12-2008, 07:59 AM

Yeah no doubt if it is just the spider gears just take it to a good shop and get i t fixed. If you need to replace the whole rear end then upgrade to the 14B that way you wont be doing this again anytime soon!

**bone stock** · 03-12-2008, 09:47 AM

its a 03 1500 z71 with the gt4 and 10 bolt and 6 lug. if i went to a 14 bolt would it still be a 6 lug?

**bone stock** · 03-12-2008, 09:48 AM

The truck has disk brakes.

**MrShorty** · 03-12-2008, 11:10 AM

From what I understand, the 14 bolt 6 lugs are pretty rare, and get snatched up pretty quickly. I'm not certain what all goes into it, but I think you can buy adapters or new axleshafts to convert an 8 lug to 6 lug, but that adds $$ to the project. It also seems that GM hasn't been as keen on the rear disks as others, so I don't know how readily you'll find a 14 bolt with disk brakes, or if it's important to you to have rear disks, or what goes into converting from disk to drum if you decide you wanted to try a drum rear.

I wish I knew more about the 14 bolt conversion to help with.

**30 Yr GM Tech Burn-out** · 03-13-2008, 01:59 AM

sounds like you need to find another mechanic that can repair rear diff problems.
A great supplier is"Randys ring and pinion" they have everything you need .

**bone stock** · 03-13-2008, 09:58 PM

yeah I think your right, I talked to a tech at the stealership and he said I would be about 400-500 in parts with a new carrier and whatever in labor. the four spider gears are sitting in there wobling around from what I'm told.