8-3/4 Rear Question.

[Chris 69]

On my '68 Charger, the rear is an 8-3/4", 742 case. It started leaking oil out the front, so now I am going to replace the seal.

This is the first time I've tried this on any car.

Questions:

1. I have the drive shaft off the differential, is the yoke retaining nut (that was behind the u-joint) left or right-hand threaded?

2. Crawling around under the rear prior to removing the driveshaft, I noticed one of the u-joint caps was missing a bolt. Upon removing the cap, the missing bolt is sheared off (sometime in the last 41 years) inside the yoke. How do I get the sheared-off bolt out?

Thanks, Chris

[lisiecki1]

so the pinion seal is leaking?  It's been a while since I've removed a pinion yoke, but I believe the threads are standard right-hand threads.

and go to the auto parts store, or your local tool supplier and buy an EZ-Out kit for that sheared bolt.

[Chris 69]

so the pinion seal is leaking?  It's been a while since I've removed a pinion yoke, but I believe the threads are standard right-hand threads.

and go to the auto parts store, or your local tool supplier and buy an EZ-Out kit for that sheared bolt.

Thank you for the information.

Yes, I believe the pinion seal is leaking.

[Chris 69]

OK, this afternoon, I have been trying to loosen the pinion gear nut.

Here's what I tried (turning the nut counter clockwise, looking at the front of the differential):

1. My 1/2" drive socket.
2. My 1/2" drive socket + hydraulic bottle jack.
3. 18" breaker bar.
4. 18" breaker bar + hydraulic bottle jack.

So far, the nut has not budged.

Any suggestions as to how to loosen this pinion gear nut?

Thanks, Chris

[lisiecki1]

Hi Chris, would it be possible for you to take a quality picture of the yoke....maybe looking at it will give me some ideas....I don't know why you're having so much trouble....every one I've ever done was fairly simple.

[Chris 69]

Hi Chris, would it be possible for you to take a quality picture of the yoke....maybe looking at it will give me some ideas....I don't know why you're having so much trouble....every one I've ever done was fairly simple.

See attached picture. Thank you!

Also, note the sheared-off bolt on one of the holes...

[terrible one]

Hey man,

I'm also facing removing my yoke and replacing this seal pretty soon. I haven't been home to try it yet, but my idea so far after trying to remove it/ keep the car from rolling, etc. was to use a socket and  breaker bar and starting the tool as far from the ground as possible, push the car forward as fast as you can. I'm thinking the weight of the car and the breaker bar on the concrete will leave the pinion nut with no choice but to give. If you don't try it first, I will! 

[lisiecki1]

Hey man,

I'm also facing removing my yoke and replacing this seal pretty soon. I haven't been home to try it yet, but my idea so far after trying to remove it/ keep the car from rolling, etc. was to use a socket and  breaker bar and starting the tool as far from the ground as possible, push the car forward as fast as you can. I'm thinking the weight of the car and the breaker bar on the concrete will leave the pinion nut with no choice but to give. If you don't try it first, I will! 

^ that is actually the way i did my first one....it was a single-trak 8.25, I left one tire on the ground and used the other tire to break the nut loose.  We still need to verify that those threads are standard threads though, I'd hate to see something that important get screwed up....

[Chris 69]

Hey man,

I'm also facing removing my yoke and replacing this seal pretty soon. I haven't been home to try it yet, but my idea so far after trying to remove it/ keep the car from rolling, etc. was to use a socket and  breaker bar and starting the tool as far from the ground as possible, push the car forward as fast as you can. I'm thinking the weight of the car and the breaker bar on the concrete will leave the pinion nut with no choice but to give. If you don't try it first, I will! 

^ that is actually the way i did my first one....it was a single-trak 8.25, I left one tire on the ground and used the other tire to break the nut loose.  We still need to verify that those threads are standard threads though, I'd hate to see something that important get screwed up....

I've been wondering about the thread direction as well. I've researched the topic on the web and can find no mention of the pinion gear threads being left-handed.

The only left handed threads mentioned in my service manual for the 8-3/4 are some bolts inside the case.

terrible one, I may try that method this weekend if nothing else is working.

Thanks.

[Mick70RR]

It's a right hand thread. I use a large pair of stilsons to hold the yoke against the garage floor and use a long breaker bar on the nut.

[Chris 69]

It's a right hand thread. I use a large pair of stilsons to hold the yoke against the garage floor and use a long breaker bar on the nut.

Thanks. I'll try that after work tonight. I have never heard of "stilsons" is that a pipe wrench?

[Mick70RR]

Yes, pipe wrench.

[TylerCharger69]

An impact air gun is what I used....and it is standard right handed thread

[Chris 69]

Finally removed the nut this afternoon. I used the pipe wrench on the yoke, a breaker bar on the nut, and my foot to push the breaker bar; and it worked! The seal has also been removed.

Now, it's time to try to remove the sheared bolt from the yoke.

Thanks for all of the help.

Chris

[ACUDANUT]

 I know this is late but in the future, use a 1/2 inch impact gun.

[Chris 69]

I know this is late but in the future, use a 1/2 inch impact gun.

Unfortunately, I do not own an impact gun. However, it is now on my long list of wanted tools (along with a compressor+air tank).

Thanks!

[mopar0166]

Yeah im doing the same right now and the impact gun did nothng

[maxwellwedge]

Beware that you may have othe newer problems as I believe those 8-3/4's used a crush sleeve and if you are lucky everything may be ok .....if your not lucky.....

Dana's do not use this method and removing and re-installing the yoke on them is ok as long as the torque is correct.

[cdr]

Beware that you may have othe newer problems as I believe those 8-3/4's used a crush sleeve and if you are lucky everything may be ok .....if your not lucky.....

Dana's do not use this method and removing and re-installing the yoke on them is ok as long as the torque is correct.

no the 742 does NOT have a crush sleeve!!! so no problem there ,it is like a dana

[maxwellwedge]

Ok - That's a good thing then....

[chargerbr549]

One thing to check after you get it back together is make sure the axle vent is not plugged if its plugged it will have a tendency to push oil out the seals. The way I check the vent is to take out the oil fill plug and use like an old rubber fuel line with a rag wrapped around it so you can seal the fill hole and blow into it, you should be able to blow air into the housing and hear it coming out the vent, if it tends to blow back in your face the vent is most likely plugged.

[fy469rtse]

Chris I'm more concerned that you should have checked for play or wear in the pinion bearings, almost always the cause of a seal going bad, if you get the factory manual for tension settings read it a couple times over then ask the guys here again to explain , not a straight forward tension to nut , I had a good friend of mine to show me and help, once shown I got it, read the manual, the nut is done up according pre load on the bearing