hey guys i have a 3.42 posi disk rear in my car and the posi is broken. i was told i need a new posi unit and i was wondering how hard they are to replace, how much they cost, what kind i should get, and how long will it take me to do it myself.

 

Get the SLP take-off Torsen one, $99. Should take less than 2 hours to replace, drive-in to drive-out. You'll need to take off the calipers; one end of the Panhard bar; remove the cover, the fluid will fall out; take out the 5/16" bolt that holds in the cross shaft, with a 6-point box wrench; the pin will slide out; one at a time, push the axles in, the C-clip will fall out, then the axle will fall out; unbolt the 4 big bolts you can see, and pull the carrier out; pay careful attention to the shims as you take the carrier out, they must go back in the same positions they came out from; unbolt the ring gear from it (the bolts are left-hand thread); installation is the reverse of removal.

 

hmm ill try to find where i can order that slp from probably slp im assuming, but the calipers i have to take the brake calipers off?

 

This is what i found on SLP online is this the part you were referring to? Part number 64501T Differential, OEM Zexel-Torsen Camaro Firebird also there is a note that this product is a 3-series differential, what does that mean,? thanks

 

That's the one.

3-series means it fits your gears: it's for 3.23 and higher ratios. It won't fit 3.08 or lower ratios.

Yes you have to take the calipers off. The axles won't fall out while the rotors are there, and they won't fall off until you take the calipers off.

Notice I said "fall out" or "off" alot.... I think this rear end is an excellent example of engineering. Think of it this way: there's nothing really holding it together, it just can't quite fall apart until you take that 5/16" head bolt out.

 

I hate to go against the advise already given, but you can't just drop the new zexel in place with the old shims and expect it to work. Well, at least not for long.

You have to set the backlash on the ring and pinion, and the bearing preload. There is no way to get around this. I just did the zexel swap and it took me a number of tries to get my backlash set correctly.

Before I pulled the old carrier/ring gear out, I took a mag base and dial indicator and checked my backlash at four different points around the ring gear. Then I pulled the carrier and swapped the ring gear to the zexel and installed it. The backlash was way off. I only had .002 to .0025 backlash. The setting is supposed to be .005 to .009. I got mine to .0075 to .009. The backlash will vary at different points around the ring gear. So just get the backlash within the acceptable range, then added a .004 shim to get the proper bearing preload.

You might just get lucky and put the zexel in and have your bearing preload and backlash right on, but it's not likely. A mag base and dial indicator are cheap. Enco has them for about $20 plus shipping.

You also need to check the bearings on the zexel from SLP. They are take out units and the bearings are virtually new, but they must have had a trained gorilla that took mine out. They screwed up the bearing cage on one of the bearings and I had to press it off and replace it. Also the zexel carriers do not come with bearing races. You need to buy two new ones if the bearings on the zexel you get are good. Do not reuse your old bearing races on the zexel carrier. Buy new ones for about $8 each. The bearings that come on the take out zexel are new enough that you can reuse them, but only with new races. If you reuse your old races, you are just asking for trouble.

You will also need a torque wrench to tighten the ring gear bolts and the 4 bearing cap bolts. And, another critical thing is to make sure you get the bearing caps back on the same side they came off of. Mark them before pulling them off. The is the first thing you should do after pulling the cover off the rear.

Good luck with you swap. I sure like the zexel works on my car. It's definately worth the money.

 

wow thanks for all that info, i am going to have to look into this a little further than i thought