pinion yoke

[Josh577]

I have an 87 gmc k2500 im fixing up with my 17 year old son. we decided we would change the rear diff fluid and the pinion seal because it was leaking. I have no experience at this and i did not do any research first. when we took the nut off and removed the yoke we didn't mark the threads, we didn't know to. we just changed the seal and hammered the yoke nut back down with a Milwaukee impact.
tonight when we test drove it there was a littel smoke coming off the yoke, it seemed to stop by the time we got it back home.
we did discover the rear end is out of square badly also on this trip but. im trying to figure out if we screwed up that yoke from hammering it back on with the impact or if the rear axle being dog leg could have caused the heat in the pinion bearing..: i really dont know

 

[CalSgt]

If you over tightened the pinion nut the preload on the bearings can be too tight.

There is a crush collar on most pinions that allows the nut to be tightened until the bearing preload is at the recommended spec. Most manuals will say the crush sleeve needs to be replaced every time but so long as they are not over torqued will usually be fine.

If you ran the pinion nut down with the UGGA-DUGGA's theres a good chance you cooked the bearings.

ETA: The other method of setting preload uses a non crushing sleeve and shims, once preload is set it can be disassembled and reassembled quickly without worry of over tightening. AFAIK this is usually only done aftermarket on GM axles.

 

[SquareRoot]

Merry Christmas. You likely torched the pinion bearing. Things just got expensive. Hey, we all live and learn.

 

[squaredeal91]

we did discover the rear end is out of square badly also on this trip but. im trying to figure out if we screwed up that yoke from hammering it back on with the impact or if the rear axle being dog leg could have caused the heat in the pinion bearing..: i really dont know

So it sounds like you're centering pin on leaf pack is broken?

 

[SquareRoot]

So it sounds like you're centering pin on leaf pack is broken?

Is that what causes dog legging? I've seen some severe cases and always wondered what exactly caused it. I guess I always assumed it was a bent frame but there was no obvious body damage.

 

[CalSgt]

Is that what causes dog legging? I've seen some severe cases and always wondered what exactly caused it. I guess I always assumed it was a bent frame but there was no obvious body damage.

I'd bet broken centering pin is the most common cause...

I saw one a while back that would shift how far it would dog leg while breaking and accelerating. It was scary to follow

 

[squaredeal91]

I've had a few broken center pins. Once on front axle from dropping into a hole night wheeling. It hurt lol

 

[Josh577]

So it sounds like you're centering pin on leaf pack is broke. well now that you mention it i noticed on the drivers side leave spring is broken where the bolt goes threw the spring eye connecting it to the truck

the leaf spring bolt eye is broken on the drivers side

 

[Josh577]

If you over tightened the pinion nut the preload on the bearings can be too tight.

There is a crush collar on most pinions that allows the nut to be tightened until the bearing preload is at the recommended spec. Most manuals will say the crush sleeve needs to be replaced every time but so long as they are not over torqued will usually be fine.

If you ran the pinion nut down with the UGGA-DUGGA's theres a good chance you cooked the bearings.

ETA: The other method of setting preload uses a non crushing sleeve and shims, once preload is set it can be disassembled and reassembled quickly without worry of over tightening. AFAIK this is usually only done aftermarket on GM axles.

uggq dugga.. lol on the brink is that you? I used an electric Milwaukee impact I assume we hit it pretty good. What’s the torque supposed to be?

 

[GTX63]

I have an 87 gmc k2500 im fixing up with my 17 year old son. we decided we would change the rear diff fluid and the pinion seal because it was leaking. I have no experience at this and i did not do any research first. when we took the nut off and removed the yoke we didn't mark the threads, we didn't know to. we just changed the seal and hammered the yoke nut back down with a Milwaukee impact.
tonight when we test drove it there was a littel smoke coming off the yoke, it seemed to stop by the time we got it back home.
we did discover the rear end is out of square badly also on this trip but. im trying to figure out if we screwed up that yoke from hammering it back on with the impact or if the rear axle being dog leg could have caused the heat in the pinion bearing..: i really dont know

How do you know the rear axle assembly is misaligned? There is a small dowel or centering pin located on the bottom of the leaf springs where the axle tube is bolted to the perch. If it is not centered and in the hole, you will see a gap between the perch and the bottom of the spring. Usually, the only reason the rear assembly is out of alignment is someone has previously removed it and did not properly reinstall, or there was damage from impact.

 

[Josh577]

i dont know how i didnt see it before

 

[SquareRoot]

uggq dugga.. lol on the brink is that you? I used an electric Milwaukee impact I assume we hit it pretty good. What’s the torque supposed to be?

On used bearings, it's basically inch lbs, like just enough to take any slack out.

 

[Keith Seymore]

On used bearings, it's basically inch lbs, like just enough to take any slack out.

That's the rotating torque on the pinion assembly after the nut is torqued (ie, 12 in lbs to spin the yoke after it's all together).

It will take some torque, like 100+ ft lbs, to run a new nut down (they are a prevailing torque type) and crush the sleeve to get to that point. This would be measured with the pinion/yoke held stationary.

K

 

[Josh577]

On used bearings, it's basically inch lbs, like just enough to take any slack out.

do you think i could loosen that pinion nut and just snugg back down for now?

 

[Josh577]

That's the rotating torque on the pinion assembly after the nut is torqued (ie, 12 in lbs to spin the yoke after it's all together).

It will take some torque, like 100+ ft lbs, to run a new nut down (they are a prevailing torque type) and crush the sleeve to get to that point. This would be measured with the pinion/yoke held stationary.

K

i have a torque wrench that just has a dial indicator on. It does not ratchet but I’m pretty sure it reads in pounds instead of inches I will have to look. Millwright at work gave it to me. Can jack the truck up with the tires on and torque that nut like that or do you have to disassemble the rear end?