A few months ago I noticed the original drum/posi rear end in my 91 Z was making some noise. Upon closer inspection The noise seemed to be bearing noise. So in talking with a friend at work he said he would rebuild a rear for me for a fair price. Since I live in a apartment it seemed wiser to find a core and build it. So the rear that was built for my car Was a 26 spline disc posi rear. It was built with a used posi, and 3.42 gears froma V6 junk yard car. Now here comes the questions....
1)Was it wiser to just rebuild the rear I had intially?
2)Does using junk yard gears affect durability or the rear?
So installed the rear end in my car with minimal fuss. Added a Summit Girdle cover, welded axle tubes, and Redline sythetic. I had no real problems what so ever other than some posi chatter which was remedied by adding some more LSD additive. Then every now and then the rear would clunk when shifting. I attest this due to the shift kit I have in my car. I asked the guy who build the rear and he said that is caused by the spider gears. So thats not the worst of it. I decided to change the fluid in the rear and the magnetic drain plug for the cover had a decent amount of metal on it. Kinda posed a question about the durability of the rear. Then I noticed the bolts that hold the diff cover on were slightly loosened. Saw a little staining from mild leakage. So I tighted up the bolts and forged on. Topped the fluid off, The rear only seemed to take a quart and a half. I have been searching and everyone seems to say 3 quarts. More questions.....
3) Can the clunk I was hearing be caused by the spider gears being worn?
4)Is seeing a little shavings on the magnetic plug nomal?
5)Is it possible that the force across the girdle loosened up the diff cover bolts?
6) How many quarts of fluid should the rear actually take?
Here is the worst part of my story. Car drove fine for a while after the fluid change. I went on a 500 mile trip with the car. Had no problems on the way there. However on the way back I started to hear some noise from the rear. Kinda a howling sound. Somewhat intermittently. I pulled the car over immediately. Looked under the car and noticed wetting on the bottom of the pig. Yoke seal was shot. So with no other choice at 3 in the morning I pushed it to the nearest town, about 25 miles away. By the time I made it I could feel some resistance in the driveline. I assume in the rear. Needless to say I had to find a way back and then went back to get the car. I did'nt drive the car around a whole lot, other than to load it on the trailer but I could hear some clicking coming from it. More questions again...
7) Is the rear shot?
8) Is there a better way to seal the yoke to prevent this again?
9) Besides broken teeth, what should I look for when I take the cover off?
10) Could the hard shift of my translossened the retaining nut on the yoke, and caused the leak?

TIA, and Be patient with me. I am still learning the in's and outs here. And suggestions on how to repair it on a budget would be apprecaited too.....

 

I think that the 10 bolt takes 3.5 pints of oil. If you had to add 1.5 quarts then it was out of oil and the bearings are prolly going to fail soon.

 

Whats funny is I filled it until the oil came out of the fill hole.

 

New gears are like 150 bucks, not worth using junkyard ones. I would guess that your friend who set it up didnt so it quite right. Sounds like he just put it all together and let it go. There is another thread on here right now about a guy who had his rear redone and the guy just reused the factory shims, didnt check anything. He will probably have the same problem soon. Next time, get the tools and learn to do it, or pay a shop to do it.

 

Well in regards to learning how to do it. Thats why I am here asking questions. I have held this site in high regards for having enough knowledge to help educate those who don't do automotive work daily. And does anyone maybe know the answers to my questions?

 

the spider gears can cause a clunk but, usually it is caused by backlash between the pinion and ring gear. (not setup right) this can cause other problems since the gears are clearly not setup properly.

 

1) yes, because it had 28 spline axles instead of 26's
2)yes, they are used, thier life span is already partially over
3) could be, probably backlash wrong, as posted above
4)no
5)probably not, on the cover, use loctite.
6)I honestly dont know. But it was posted above
7)More than likely yes. At least the gears and/or posi
8)what was the process?
9)a whole multitude of things. chunks of metal are a dad giveaway.
10)I dont think so

 

Rip the cover off, I guarantee you will find that some of the teeth on the ring gear have EXCESSIVE wear on the insides. Possibly some are missing as well as part of the pinion gear. My car was howling one day on the way to work. Parked it. After work, got in the car, put it in reverse, stopped, put it in drive, let it idle forward a bit as I usually do and I heard a bad sound from the rear. A few more revolutions and another bad sound. Kept happening and I was scared as hell to drive it, so I parked it and had it towed. When I ripped the cover off, there was metal everywhere, and 1/5 of the pinion gear was sitting at the bottom of the pumpkin along with quite a few of the ring gear teeth. A LOT of resistance was in the drivetrain, and moving it only made it worse. You're lucky though. My drive to work is about 5 minutes, and in those 5 minutes there is when it started its howling. By the time I decided to go home after work, it broke down before I got out of the parking lot.

Basically, you need new gears. The old gears shouldn't have been re-used, and if they were needed to be re-used, they should have been set up properly...