8.75, 741 pinion seal replacement.

[rp23g7]

So Its time to replace my seal, its been leaking a few drips each day on the garage floor. Just gotta find a really big socket now.

I checked the fluid, its still fine, but its got some pressure in there. Wondering if the vent is plugged. How do you clean it? Does that little cap pop off?

Going to do the axle seals too, as one is leaking a bit. While I have the axle out I may as well adjust the back lash.
How do you do this? I googled it, but all I get is the same axle info, on all the sites, but none really explain how to set the back lash.

Sigh, seems like I have taken my wheels off and on 100 times in a week dealing with that stuck wheel cylinder too.

 

[Meep-Meep]

The vent is a bolt that unscrews and the cap is crimped over the hollow bolt so don't pry it off. You can remove it and spray it with brake clean or something.

The axle end play is .008" - .018" and is adjusted by the star wheel adjuster nut at the bearing retainer plate on the axle. There are two axle seals per axle. One in the housing and one in the bearing retainer plate. The axle bearings MUST be packed with grease like front wheel bearings and are NOT lubed by the rear end oil.

The trick to adjusting the end play is to have the 5 retainer nuts on the non adjuster side tight and the nuts on the adjuster side as tight as possible so that you can still move the adjuster nut. Make a spanner or use a brass drift and hammer to move it. When you get the desired clearance tighten the retaining plate nuts completely and recheck the end play. If it's tight back off accordingly and recheck. Lock it with the curved metal tab off one of the flange nuts.

Note: If you have an old clutch style sure grip and the buttons are missing, you will never get the end play correct.

 

[70WM21 W1 V6B]

Also it may not be a bad idea to get a FACTORY CHRYSLER (Not Chiltons) service manual from Bishko for your car. It covers everything and its what the dealership techs use to fix your car back in the day. They are well worth 50.00-60.00. Full Pictures, descriptions, torque specs, step by step instructions, etc.

 

[Redpolara]

If the 741 runs a colapsable spacer for the pinion bearing preload, i'd be reluctant to replace the seal without fitting a new spacer as well.
Over the years i've seen (some)pinion bearings fail in a short period after someone has replaced the seal only.....that's if it runs a colapsable spacer???
It's there for a reason and only designed to be used once....as I said,that's if it runs one???

 

[Meep-Meep]

You are absolutely correct, but just as an FYI the 741 and 742 do not use a colapsable spacer (crush sleeve). Pinion bearing preload is set with shims.

 

[cudamark]

If your rear end is building up pressure, the seals may be ok once you get the vent working again. I've never seen one go bad but I assume it's possible. How do you know there is pressure inside? Air escaping when you pull the filler plug?