*&%$# pinion nut

[79F250]

Okay, doing rear pinion oil seal....new seal in place, proper depth, pinion flange on, pinion nut won't go on all the way. yes I'm using a new pinion nut. pinion seems to rotate fine, don't if it's supposed to be tight in the housing or if a little play is normal. I had use a dead blow hammer to get the flange off and on, even with grease on the splines. what am I missing????

 

[inkpot]

Are you setting it with a torque wrench or trying to replicate the old position?

 

[79F250]

Are you setting it with a torque wrench or trying to replicate the old position?

I'm just trying to get the damn thing on. it only goes on about 2/3's of the way. the stake collar is nowhere near the stake groove on the pinion shaft.

 

[79F250]

it doesn't help that we just had a torrential downpour. I'll get reorganized and take a picture. it will take a few minutes.

 

[79F250]

 

[79F250]

As you can see, there is way too much thread exposed. The nut I took off had about two threads showing above the stake collar.

 

[bigredmachine]

is th pinion flange seated all the way on the diff, maybe it needs some persuasion to go back on as you mentioned that it needed help coming off

 

[79F250]

is th pinion flange seated all the way on the diff, maybe it needs some persuasion to go back on as you mentioned that it needed help coming off

Maybe. There isn’t too much space left between the dust shield and the differential housing

 

[bigredmachine]

are the threads all chewed up on the pinion shaft causing the nut to bind? pull the flange and check to make sure that everything is clean and ready for assembly and give it another shot

 

[ccslider]

Is it a new nut? You reused the crush sleeve? This could be a ticking time bomb

 

[bigredmachine]

Is it a new nut? You reused the crush sleeve? This could be a ticking time bomb

its totally fine to reuse the old crush sleeve, just don't over torque it or youll need a new sleeve

 

[79F250]

are the threads all chewed up on the pinion shaft causing the nut to bind? pull the flange and check to make sure that everything is clean and ready for assembly and give it another shot

No, threads are fine, it threads up fine spins easily, it just doesn’t go all the way to the end. The only thing I can think of is that when I had to remove the pinion flange with a hammer is that it pulled the pinion out of the ring gear

 

[shocktower]

Try the old nut and see if that goes on, the new nut could be bad

 

[chap79]

I’ve personally experienced getting the wrong pinion nut before. Seems like they start to thread and then hard stop.

 

[79F250]

Try the old nut and see if that goes on, the new nut could be bad

I’ll try it.

 

[inkpot]

I would agree that the pinion gear has moved inward along the ring, maybe due to you needing to tap the yoke onto it. Grab the flange and pull back hard! You may need to rotate it a bit so it will follow the curve of the gear teeth.

 

[79F250]

I would agree that the pinion gear has moved inward along the ring, maybe due to you needing to tap the yoke onto it. Grab the flange and pull back hard! You may need to rotate it a bit so it will follow the curve of the gear teeth.

I think I’m f%#ked. There’s no way I can move that flange without a hammer

 

[79F250]

So much for a simple pinion seal change.......

 

[jynx]

I’ve personally experienced getting the wrong pinion nut before. Seems like they start to thread and then hard stop.

Your pinion splines may be jacked, but this sounds like a more likely culprit. I didnt think the pitches on the nuts, even t-case nuts, changed over the years, but may have. If it strats fin thw first couple turns and then comes to a dead stop, then it sounds like the thread pitch is off.

Of course if you pinion splines are so jacked that you are having to drive the flange off with a hammer, then it is also likely that it isnt seating and the nut cant pull the flange down without more torque. If this is the case, your only issue is going to be when you get close to right on the sleeve as you dont want to ove crush the old one.

What year is your truck (sorry on mobile, cant see signatures). Can you pull the shafts and pull the whole third out? If you could get it out and on the bench, you might be able to tell more about it. If it is a 91 or 92, pull the rear cover and see if you can see anything inside the diff.

 

[79F250]

Your pinion splines may be jacked, but this sounds like a more likely culprit. I didnt think the pitches on the nuts, even t-case nuts, changed over the years, but may have. If it strats fin thw first couple turns and then comes to a dead stop, then it sounds like the thread pitch is off.

Of course if you pinion splines are so jacked that you are having to drive the flange off with a hammer, then it is also likely that it isnt seating and the nut cant pull the flange down without more torque. If this is the case, your only issue is going to be when you get close to right on the sleeve as you dont want to ove crush the old one.

What year is your truck (sorry on mobile, cant see signatures). Can you pull the shafts and pull the whole third out? If you could get it out and on the bench, you might be able to tell more about it. If it is a 91 or 92, pull the rear cover and see if you can see anything inside the diff.

It’s a 97 40th anniversary. The splines looked good, and the pinion threads are good too. It’s almost like the splines are an interference fit.