Rear End Howling

[Newman434]

I replaced the posi unit in my 8.5 rear which fixed the slipping problem but I still have a howling as I accel and decel. There is almost a grinding noise that comes and goes also and I'm trying to find out what the problem could be. The car had leaked out the rear fluid and ran wiping out the clutches and gears. I replaced those but left in the stock ring and pinion, could this be the problem. The axle bearings felt ok as there was only a small lip on the axle itself. They were re-greased and installed.

What should I check to track down and fix the noise? I had driven teh car once and not heard anything but after that I replaced the pinion bearing and now the noise is here to stay.

 

[bowtie81]

did you put any rear end conditioner back in? do the gears have the proper lash?

 

[Newman434]

The gear oil is 2 qts of 75-90 with a bottle of friction modifier. The lash should not have changed much if any as everything was put back in the way it came out (spacers and shims)

 

[bowtie81]

there's a certain tolerance that has to be maintained and even if it's out .002-.005 it could make a difference. you should check with a dial indicator.

 

[grizwald]

i thought that anytime you CHANGED carriers or posi units, you had to re-shim it to get the proper backlash. the only way that the theory of "putting it together the way it came apart" would apply is if you had your old posi usnit rebuilt, as you have the shims that work with that carrier. am i wrong?

 

[SSedan64]

I think where you messed up is when you changed the Pinion Bearing. That will change the Pinion depth & backlash. Did you change the Carrier bearings when you rebuilt the Posi?

Ooops, I see you replaced the Posi. Grizwald is correct. Those Carrier shims normally wont match the old Carrier shims.
Changing Gears, Carrier or Bearings requires reshimming Carrier & Pinion.

 

[78maliburat]

NEW CRUSH SLEEVE ](*,)

 

[t5montecarlo]

good point. You did not mention the crush sleeve.

 

[SSedan64]

Yep, Crush Sleeves & Pinion Nuts should only be used once. Replacing a Pinion bearing requires resetting Pinion bearing preload with the Carrier/Ring gear removed.

 

[Robert1320]

I replaced the posi unit in my 8.5 rear which fixed the slipping problem but I still have a howling as I accel and decel. There is almost a grinding noise that comes and goes also and I'm trying to find out what the problem could be. The car had leaked out the rear fluid and ran wiping out the clutches and gears. I replaced those but left in the stock ring and pinion, could this be the problem. The axle bearings felt ok as there was only a small lip on the axle itself. They were re-greased and installed.

What should I check to track down and fix the noise? I had driven teh car once and not heard anything but after that I replaced the pinion bearing and now the noise is here to stay.

You ran it out of lube! Did you replace any bearing? What did the ring and pinion look like? Pics?