Swapping Gears

michaelandmeganc · November 26, 2014

I have future plans to swap the 3.73's in my Z to 4.10's, anyone with experience with rear-ends as they are not my specialty, please chime in. In the process, what should I change out? Obviously the gasket. Should I change out seals, anything else?

Reason for changing gears, I'm going to wait until I swap the 300,000+ tired 5.3 engine for another lower mileage one, then do the gears at the same time. I think the 5.3 will be much happier with the 4.10's and won't have to work as hard being that this truck doesn't leave the driveway without a trailer pulling 4-5k# on any given day. I had a 4l60 fail not long ago and I think it would have held up even longer if I wasn't working it so hard pulling with the 3.73's.

00Silverado4x4 · November 26, 2014

If you've never rebuilt an axle I don't think you should try it. There is all kinds of torque values and special tools needed for the job, not to mention the gear sets you will need. It's not just a "pull out old parts and put in new ones". If you don't believe me look it up on YouTube or Google search the procedures. If the gears aren't set up right you will just destroy gears and have to do it all over again. I for one, have also never done this so if I were to ever re-gear I'm taking it to a shop. Also remember that whatever you have done to the rear also needs to be done to the front axle as well. Both axles have to have matching gear ratios or you will wind up taking out your transfer case and who knows what else.

8.1HD/ALLISON · November 26, 2014

+1. Ive rebuilt diffs. with that many miles you should replace ALL bearings and seals & pinion crush sleeve. Make sure you are familiar with setup and have all specs, tools. .005 of an inch can make or break you.

michaelandmeganc · November 26, 2014

I hear you guys, and I think you may have been mislead by my post and my intentions. I'm BY FAR not planning to do the axles myself. My father was one of the top of the gun dealer mechanic and wouldn't even mess with them himself. I know where and who to let work on them, I was just asking if anyone had any experience on what parts I would need to order. Obviously gears, possibly a rebuild kit that comes with everything? I'm just not sure how these things work. I figure there was someone with experience here that's done it before. So from the sounds of it, when they do the gears I need to pick up seals, bearings, and a pinion crush at the same time. That's the information I was looking for.

02suburbanZ71 · November 28, 2014

Yea you should take it to an offroad shop and a couple trans shops for estimates. You need to dial the backlash in and that can be confusing for someone with little axle experience. Better to pay the extra now for peace at mind.

02suburbanZ71 · November 28, 2014

Also dont forget if its 4x4 both axles will need converting and you will need to calibrate the pcm for the gears.

trapperman83 · December 1, 2014

I've done a few gear swaps and my worst part was the crush sleeve if u go to far it's over, setting gear depth and backlash has to be right or things go bad fast.