jjcuff1

I just had my tranny rebuilt and runs great he also lubed the rear diff. he said it was shot since sat so long had low fluid and looked like water.


Car seems to run fine but once I go above 20 and definitely by 45mph+ i get a constant heavy drone whining in the rear and it is RPM related.

Car shifts and feels ok no clunks or grinding back there. I think it is a stock 2.73 10 bolt posi for 88 iroc auto.

Is there anything I can check or lube considering it was just serviced? Is it the backlash of the rear diff worn shims?

Ozz1967

iTrader: (4)

IS the whine heavier under load and goes away if you take your foot off the gas?

The whine is the ring/pinion bearing iss going bad, no adjustment I know of that can fix that other than replacement of the ring/pinion gears. It is possible the gears are good and only the bearings need replacement.

jjcuff1

Ozz, thanks for the quick reply. yes more or less heavier whine under load. The shop just pulled the pumpkin and lubed it up. So can I replace the bearing with hand tools and jack it up in the garage or I need to pull the half shafts, wheels, u joints?

big gear head

You said RPM related. Did you mean speed related? RPMs would usually mean a transmission problem. Speed related would usually be the rear end.

If a rear end sits for many years then rust will form on the gears and bearings. Anything that is above the oil level will rust. You might have bad bearings. The hardest part of changing bearings is setting the preload on the pinion bearings. You must use a new crush spacer and crush it to get the correct preload on the bearings. This can take 300 foot pounds of torque or more on the pinion nut to crush the spacer. This requires some heavy tools and strong arms. You will also need a preload gauge to check the preload. Yes, it will require a complete tear down of the rear end, and you will need a press to remove and install the bearings.

jjcuff1

Yes speed related and yes sat for long time, makes sense probably shot. ;(

Well is it easier then to buy a new gear set like a 3.44 and just a shop to swap out, new bearings lubed etc for all the trouble? what will that be? $300 for the gear set (assuming I reuse my carrier or that need rebuilt too) and $300 labor?

big gear head

If you have a 7.5 10 bolt, and if it has a 2.73 gear then you will have to get the special thick after market 3.42 gears to fit your 2 series differential. The gear will probably be around $225 and a good installation kit will probably be around $150. Labor might run from $300 to $600, depending on where you are.

Ozz1967

iTrader: (4)

I would't do that myself. There are youtube videos on how to do it. I would recommend however, that instead of the crush sleave, you get the solid pinion bearing from Ratech.

big gear head

Many people do prefer the solid bearing spacer. I've found that it's harder to set up the solid spacer, but others would rather go through the steps of shimming the spacer than to strain themselves by trying to crush the crush spacer. It's just a matter of opinion. I've got some special tools that I made to make it easier to crush a spacer, so that's the easiest way for me to do it. If you don't have the tools to crush a spacer then the solid spacer might be easier.

Ozz1967

iTrader: (4)

The solid bearing is also stronger than the crush sleeve is lending to more rear-end strength overall. Useful if you're running 300+hp motor.

big gear head

I've been hearing that for most of my life, but I've never had a problem with the crush spacer. I've used them in many rear ends that took a pretty good beating and as far as I know there was no failure due to the crush spacer. I'm not saying that the solid spacer isn't stronger or better, but I haven't had any problems with the crush spacer. I will admit that if I'm building a rear end for a very strong drag car I will use a solid spacer. I've got a solid spacer for a 7.5 that has been sitting on the shelf for many years and I've not had a use for it yet. If anyone feels like they need it i'd be glad to let it go at my cost.