Rearend problems....

[lukecp]

I went to go put a new rearend yolk on my truck today. The truck is a '72 C10 with a coil-spring 12 bolt. I removed the driveshaft, and counted the number of threads on the nut that holds the yolk on. There were 2 threads showing on the bolt. So, i removed the nut, took off the old yolk, and went to put the new one on. The new yolk was a little different. On the old yolk, the U-joint cap bolts simply screwed into the yolk. On the new one, the hole was threadless and i had to use nuts to hold the U-joint on. Anyway, i put the yolk on, and torqued it down until 2 threads were showing. I noticed that the wrench was pretty hard to turn. So, i finished up the job and went to drove the truck. About 75 yards down my road, going about 30mpg, a loud deep moan started to come from the rearend. Immediatly, i stopped and drove the truck back in reverse. Over 10mph in reverse, the moan came back again. It also seemed that when i was backing up a hill, it "jumped" a little bit, like the teeth on the gears were skipping. So, i am thinking that the two yolks were different thicknesses, and i overtoruqued the pinion nut when i put the new one on. What would i have destroyed by doing this? Just the pinion crush sleeve, or the whole ring and pinion? I only drove the truck 150 yards tops. What should i look for when i pull the rearend cover off tomorrow?

[crazy longhorn]

I wouldnt think you would have problems with the gears in that short distance, but you will know when you pop the cover. I would take a good look at the pinion bearings, & just check for anything unusual. Best of luck.....crazy AL

[lukecp]

Ok, maybe i wont be out a couple hundred bucks then . But if so, it would be a good excuse to upgrade to a set of 3.42's. Anyone know what the torque spec is on the pinion nut? Also, when i put the new yolk in, it seemed to have some play up and down, as well as forwards and backwards. It moved about 1/16 of a turn, and maybe 1/16 of a inch out when i jiggled it around.

[COBALT]

One yoke wasn't longer than the other, was it? Just curious.

[lukecp]

Thats the thing. I was stupid and didn't measure the yolks. They looked pretty close though. So, if i overtorqued the pinion nut, what will i have to replace?

[crazy longhorn]

If you can feel that the pinion is loose, you may have lost a bearing.......thats not good for the gears, & you will need to check them over good for any chips or obvious damage. Its hard to really say without tearing the diff apart tho. good luck.....crazy AL

[basketcase]

When you get it up in the air with the drive shaft out you should be able to turn the axles and feel if it's rough or seems tight. You might be able to install a new crush sleeve and torqe to proper specs and save it. It could just be too tight. Don't wory about the threads showing, just the torque reading.

Tom

[lukecp]

Here is what i found when i pulled the cover. The carrier (i think its the carrier, it is the bowl shaped device that the ring gear bolts to, and has 4 smaller gears on the inside) has marks on it where the pinion had rubbed on it. When i turned the wheels, they would turn smoothly over the open part of the carrier, but when the pinion hit the closed part, it would make a grinding noise. So, the pinion is too far towards the rear of the truck. This means i undertorqued it, right? So, when you torque down the pinion nut, it pulls the pinion gear towards the front of the truck, right? Oh, all the gears look great, besides the front of the pinion where it hit the carrier. How should i adjust it so the pinion won't hit the carrier?

Oh, almost forgot. Both yolks are the same sizes in all dimensions. I measured them. The only difference is how the U-joint is held on.

[mikep]

The purpose of the crush sleeve is to set the pinion depth. The pinion depth being how far into the casing the pinion gear goes. If it goes too far the gear mesh is adversely affected. You cannot simply replace the crush sleeve and torque it to a standard spec and expect it to be at the correct depth. It doesnt really work like that. The crush sleeve is not a torque limiter. It is means of allowing the gear to sink into the carrier so that the proper gear depth is attained. My guess would be you have damaged either the ring gear or the pinion gear or both. Theres no easy fix here. If you want to get walked throught he process of setting up a rear end we can do that but it takes a few specialized tools you'd have to buy ( Theyre always nice to have ) for $120 or so. The gears may be damaged though and might need replacement. Gears CAN be destroyed in a city block if the pinion depth is off by a good bit. It sounds like it might have been. The exposed thread count might have been the same on the new and old yokes but you didnt take into account the depth of the yoke . a few 10's of thousandths of an inch off of the proper gear depth will destroy a gear set Pronto.

Your best bet is probably a replacement rear end unless you like learning new skills ...a lot .

[lukecp]

I measured the depth of the yolks, and they were exactly the same. The problem is that somehow, after i installed the new yolk, the pinon went in too deep. I popped the cover, the ring gear looks almost perfect. The only problem that i can see is the the pinion is too far forward, and contacted the carrier. The only wear that i can see on the pinion gear is just a little bit on the very front, nothing at all on the gears themselves. So....how can i adjust this? I really dont want to replace the rearend now...especially since everything looks fine on the inside.