Diff puddle

[dodj]

Well I just noticed an oil stain about 12" across under my diff. It's a 489 with the crush sleeve still in it. Can I replace the seal without using a new crush sleeve? Of course this may be an indication of where the slight vibration I get at speed is coming from.

[GoodysGotaCuda]

Replacing a seal and or yoke and reusing the crush sleeve has certainly been done before, successfully too. The biggest concern is with getting the right torque on the pinion nut without further crushing the sleeve, but not leaving it too loose either. A FSM might have a torque spec they recommend, perhaps Dr. Diff might have a number as well. I have also seen people mark the pinion nut against the pinion shaft and return the nut to that same position.


Be sure to smear RTV around the outside of the pinion seal, between the case and seal. Even if there is a little rib or sealant on it, I've seen many axles [Dana's at least] that needed that thin layer of RTV just days after installing the seal. Which might be your case as it is.

[1 Wild R/T]

As Goody said, mark the nut to the pinion & count the turns so it goes back the same...  When I've done it I use red loctite as it seals but also prevents the nut backing off...

[brads70]

vibration.... might be a good time to pull out the gear pot to inspect? 

[73restomod]

vibration.... might be a good time to pull out the gear pot to inspect? 

Generally, if you have a leaking seal, its a sign of bearing/bushing wear. Or if you have a load of power in your ride it is possible to compress the crush sleeve further when the pinion tries to climb ring gear during hard launches. As good a time as any to rip it out and install a Dr. Diff, or equivalent, Crush sleeve eliminator assembly in my book, which eliminates a weak link from the rear in the process.

[GoodysGotaCuda]

Generally, if you have a leaking seal, its a sign of bearing/bushing wear. Or if you have a load of power in your ride it is possible to compress the crush sleeve further when the pinion tries to climb ring gear during hard launches. As good a time as any to rip it out and install a Dr. Diff, or equivalent, Crush sleeve eliminator assembly in my book, which eliminates a weak link from the rear in the process.

Gotta have the traction if you have a load of power. I think you'd be hard pressed to have crush sleeve problems on the street or even on the strip with an auto. Drag racing on slicks, with a trans-brake/manual trans would be a different story however..

[dodj]

Gotta have the traction if you have a load of power. I think you'd be hard pressed to have crush sleeve problems on the street or even on the strip with an auto. Drag racing on slicks, with a trans-brake/manual trans would be a different story however..

Nitto NT05 315's and a manual trans. But I don't have LOADS of power, just a 76 440 with 70 magnum internals.

As Goody said, mark the nut to the pinion & count the turns so it goes back the same...  When I've done it I use red loctite as it seals but also prevents the nut backing off...

Think I'll do this to get thru the summer and look at a more permanent solution for a winter project.

[Cudakiller70]

vibration.... might be a good time to pull out the gear pot to inspect? 

You might want to consider this!    I am glad I took mine apart. It was only wet not yet dripping. Found the pinion was loose preload lost, only took 1 inch pound to rotate pinion and carrier! Also checked gear pattern contact and it wasn't the best and backlash wasn't right at all! I think my pinion seal started to leak because the pinion was moving around. Attached is a picture of the small pinion bearing, both pinion bearings looked like this, they would have failed sooner or later. Mine is a part, have a new crush sleeve eliminator to put back in, just waiting for some more stuff from Dr Diff. Didn't find what went wrong yet, no smoking gun, nothing obvious. Jim

Picture isn't showing well, race and bearings have imprints from Contaminants, not sure what it is but race and bearing are rough. Carrier bearings showing a little also. Jim

[DocMel]

IMHO have the whole dif inspected and rebuilt.  Its a over 40 year old rear end.  I had the same issue, and a slight vibration that I couldnt isolate.  Wasnt just the seal, bearing and gears were worn

[73restomod]

I have seen 10 bolt Camaro rears having pinion crush sleeve problems on street tires, with as little as 325 to the tire. Saying no mods to the rear end otherwise. The other thing is duty cycle, repeated use/abuse can cause micro compression of the sleeve which adds up. I do not trust crush sleeves. Only reason OE's use them is to cut down on time on the assembly line. The $40 it cost to do the upgrade while replacing the pinion seal is worth it to me, and it gives you peace of mind.

[burdar]

If your yoke has a groove worn into it from the seal, they make a repair sleeve.  They make them for harmonic balancers too.

[734406pk]

Agreed... A leaking diff can be the sign of much larger problems. I would pull the diff assembly and repair as necessary. Cheap insurance! Go for the crush sleeve eliminator for sure for high horsepower applications. Dr Diff has the parts you may need.  The 8-3/4" rear is not hard to rebuild.

[brads70]

Scott, how did you make out with this? Did you pull the gear pot? 

[dodj]

Hi Brad 
No i did not pull it yet.  I just finally got the 440 running again and then packed up the 5th wheel and we are on our way to Yellowstone National park.
I'm thinking of buying a new chunk from Cass. I like doing things myself but people keep telling me it is difficult to set up a rear end properly
Without someone experienced to help.

[brads70]

Hi Brad 
No i did not pull it yet.  I just finally got the 440 running again and then packed up the 5th wheel and we are on our way to Yellowstone National park.
I'm thinking of buying a new chunk from Cass. I like doing things myself but people keep telling me it is difficult to set up a rear end properly
Without someone experienced to help.

I'm jealous! Yellowstone sounds amazing! We are just packing up the trailer too for a week at Algonquin. All new from Cass sounds like the way to go. Heck you could drip by and pick it up right from Cass! Have a safe/enjoyable trip! Take lots of pictures!