ZR2 rear axle in a 4 door questions
 

Hello guys, iv been part of this forum for a couple of years, but this is my first thread. So before anyone assumes that i didn't use the search bar, i have. There are still a few things im not 100% sure about, and i want to make sure i know before going ahead with the swap. Soo i have a 1997 gmc jimmy 4 door, its got a rc 2.5" suspension lift and a 2 body lift on the way. So the reason i want to swap out my rear diff is because im getting alot of viberation and noise from the rear diff, and the fact that the rear axle width doesnt match the front has always been something that has bothered me. So now on to my questions...my truck has rear drums, will converting to disc be an issue with the master cylinder. Second of all, someone mentioned parking brake cables need to be changed. Which ones need to be used? Will the u joints on my stock shaft bolt up to the yoke on the zr2 axle? And last question is do i need to swap in the zr2 front diff even though my truck has 3.73 gears? So let me list the questions for ease of answering.
-drums to disc, will it be fine?
-parking brake cables?
-ujoints?
- just the rear diff? Or do both have to be installed?
I appreciate you guys taking the time to read this, i hope you guys can help me out!:)

Drum to disk will be fine no issue there. You will probably need a conversion u joint. Not sure which one but I know okiedoak had to use one when he swapped in a z axle. Parking break cable will be a combo of both using the z cables at the axle and attaching them into the current cables at the adjuster I believe. As long a you already have 3.73 gears you will be fine with jut the rear swap but anything other than 3.73 will require you to swap so you match front and rear.

Thanks man! Im gunna have to look into the conversion u-joint. But i seen someones build and they didnt need one so if anyone else knows anything please share!

Try pming el_Beautor he has a z axle and is happy to help I'm sure. It could be because okiedoak has an envoy version I dunno for sure sorry.

97GMC, I got your PM but I'll post here too for anyone else looking for info. Yeah, on my swap I did not have to use a different U-Joint. my existing U-joint bolted right up to the ZR2 axle. Not sure what the difference is between mine and Oikidoaks other than his being the Envoy/Trailblazer version of the S-series.

Like Rex said, the front diff does not need to be swapped if you have the 3.73 gears already. The only real reason to swap at that point would be if you found a donor Z with the cast-iron front diff instead of the aluminum diff. The iron diff is stronger, but other than that it's identical.

As for the brakes, its an easy swap, and you don't need to change anything with the master cylinder. You do need to get the hard-lines for the ZR2 axle. Your existing lines won't fit on the wider axle. The park brake cable will need to be changed. I think the easiest would be to just get the whole cable, right from the pedal to the axles. It's not very expensive new, and if it's in decent shape you could always just pull it from your donor vehicle too.

FYI, once you put on the ZR2 axle your rear end will be slightly wider than the front. The difference is less than the difference on a stock setup, but I did end up putting my 1.25" spacers on the front after my swap. The ZR2 axle is about 3.5" wider than the normal non-Z 4x4 axle, and the non-Z axle is about 2" - 2.5" narrower than the stock front end.

If you have any more questions let us know.

What are you doing about a sway bar?

I havent run a rear sway bar in about a year, dont regret taking it off one bit

You drive slow or you like a lot of understeer

I didnt build my truck to be a race truck, yours is lowered mine is lifted