9" front seal replacement????

[69MyWay]

I just got my replacement 9" in my Camaro. So far it is quiet and smooth.

The problem is it is pouring oil out the front seal. The seal appears to be new but is dumping the oil out. There are no excessive wear grooves in the yoke.

It was not leaking on the previous unit.

Question is, can this be replaced with the unit in the car?

Can I just pull the yoke then pop the seal and replace?

Thanks,

Chris

[ohcbird]

That's the beauty of the 9"; you can pull the pinion out in minutes. It won't affect anything else- unless you try to drive it w/o the pinion!

[69MyWay]

I tore it down today. Very simple, like you said.

Went to Napa for a new seal and they can't match it up.

Went back to the guy I got the diff from and he gave me a seal, but it is a tiny thin thing.

I am taking the drive shaft to be balanced Thursday and will see if they have a good quality seal there.

The 9" builder used a junk yoke to set it up that had super deep groves in it. It appears pulling that on and off cut the new seal. My yoke is nice and smooth.

I assume I am going to run the nut back down on the yoke as tight as I can with some lock tight.

[Y-TRY]

If the pinion nut is loose it will leak, also. Tighten that bad-boy down until your compressor runs out of air!! Also, incorrectly installing the crush collar will leave some slop in there which will have the same effect.

Good luck.

[ohcbird]

Just remember to get the pinion preload set. Also- keep in mind it's INlbs, not FTlbs.

[69MyWay]

You see guys, this is where I get confused.

The guy that built the chunk for me told me to run the pinion nut down as hard as it will go with my air impact.

My buddy at the local GM dealer told me to pull the wheels off the axle, replace the seal, set the yoke in, run it down, then set the inch pound and tighten until there is about 30" lb of drag.

The local driveline service shop told me to wiggle the yoke in one hand and tighten with the other until it is just snug.

Another tech told me to leave the seal and yoke off, run the nut down (I really don't think this applies to the 9"), and set the drag. Then count the exposed threads. Then install the seal, install the yoke, run the nut down with lock tight to the same thread depth.

I have read on the net, but all sites I picked up simply discuss the initially set up of the pinion crush sleeve and something about using as much as 170' lbs to set the sleeve prior to running the inch pound test.

Different opinions here too.

Dang...I am so confused!

[ohcbird]

Yeah- it is confusing because your using 175-odd LBS to set a rolling load of about 12-15 inlbs (used gears). You need the ooomph-torque to crush the sleeve initially, then take it slow to get up to the pinion preload.

What company's gear are you running? Sometimes it also make a difference, as street & drag gears are different.

The guy who built it for you? Isn't this the same chunk that leaked??? Just thinking out loud...

[69MyWay]

Originally Posted by ohcbird

Yeah- it is confusing because your using 175-odd LBS to set a rolling load of about 12-15 inlbs (used gears). You need the ooomph-torque to crush the sleeve initially, then take it slow to get up to the pinion preload.

What company's gear are you running? Sometimes it also make a difference, as street & drag gears are different.

The guy who built it for you? Isn't this the same chunk that leaked??? Just thinking out loud...

Yes, same guy, second chunk, fourth swap out due to issues.



The thing is, he is known for doing good work. The seal leak is clearly due to using the junk yoke to set the unit up, then yanking it and putting the good yoke on.

Now...as far as chunks going bad. I took the driveshaft out to have it checked. It had some issues. In fact, I had a 1996 caprice shaft that I had them cut down and put the camaro tail on (special conversion joint to the 9"), and balance up for me.

Technique? I went with the cram the pinion nut on with all the air power my wrench would produce at full pressure and the parking brake set on the axle. Took the car out last night. So far the rear is quiet (Thank God! )

There is also now no vibration issues. It was hard to tell before how much was the rear or what. I also had all four tires re-balanced while the shaft was out.

The car seems very smooth.

I have a theory that may get my rear end guy out of the dog house. Maybe the bent driveshaft was setting up a frequency that was causing the pinion nut to back off a tad over the miles (remember, the rear failed after running the car several hundered miles before), then brining on the noise.

Time will tell, but I am out of time since I am transfering out of here next month, so we will see...............

THANKS GUYS!