1st & 2nd GENGuy
Nov 23rd, 99, 02:19 PM
I am in the process of rebuilding the rearend in my 1978 Z28. It is a 10 bolt 8.5" ring gear with 342 gears. It was whining when coasting and it was only a one legger. I want to upgrade to a posi and replace the bearings and seals (axle, pinion, & carrier). The gears appear okay (futher inspection required). I would like any suggestions that anyone has (dos and don'ts) plus suggestions on where to get the best prices??? PS: I have done a differential replacement but not the pinion gear bearing and seals.
Nov 24th, 99, 07:09 AM
If you haven't done one before, my suggestion to you would be to have a good driveline shop do the work. The parts are expensive, and if not done correctly will cost you big $$ later to fix. There are to many critical areas in a rearend to do it right the first time. I know, I work in a driveline shop and we get vehicles in all the time where a regular repair shop doesn't even do them right, so we get to fix what they messed up.
Most regular repair shops don't do enough of them to be good at it. It's not that they are incompetent. It is a specialized area, and best left to those with experience.
Check out these sites:
70 & 1/2 RS
SB406 & M20 4spd
70 Malibu 350/TH400
Gold member #103
Nov 24th, 99, 09:19 AM
Scooter is right, unless you really know what you are doing, get it done in a good shop. It is way too easy to mess it up. A friend of mine did his 12 bolt rebuild by himself, and it took nearly 2 weeks. It was done right, but only because of countless hours of making a few custom tools, and measuring, then re-measuring, adjusting and then measuring it again and again. As scooter pointed out, if it's done incorrectly, you will tear it up in no time. I'd replace the pinion and ring gears if you are doing that much of a rebuild. No point in stuffing loose parts into a completely rebuilt rearend. Summit racing has quite a variety of gears.
Nov 24th, 99, 10:21 AM
I would argue that if you never try it, how will you ever learn. Even the pro's had to set up their first rear end.
I just finished tearing down my 12-bolt (3.07/open)and re-doing the entire thing. I put in new Timken bearings, new Auburn Pro Limited slip differential, and a set of slightly used 1969 3:31 gears.
Doing the job at home did take some creativity (along with some borrowing of tools). However, now I have a rear end that (1)I now know much more about and (2) the satisfaction of trying it myself.
If it does make noise, It will go directly to a shop for re-adjustment...but at least I gave it a try.
1st & 2nd GENGuy
Nov 24th, 99, 12:57 PM
I already did the differential in my 88 chev pickup and it still is working but I did not mess with the pinion!! Got the 78 the rest of the way apart. The gears are slightly worn but still look okay (0.013" backlash before removing). The carrier is not too good, bearings on driver's side are pitted (side the noise was coming from) and the spider gears are really shinny. The axles are alittle tarnished at the bearing contact area but mic out almost the same as the nontarnished areas (<0.001" difference). Only one thick shim on each side of the carrier (amazing how GM can do that [my truck was the same]). The pinion seems okay, I do not think I am going to mess with it (will check alittle more). Everything is cleaned-up and all I have to do is wait for UPS to show up. Found an auburn (standard unit) and install kit (including axle bearings and seals) for $380. Let you know in a week how it all turns out!!!