I drove around 120 miles @80mph. Got off freeway and smelled something hot. All the brake rotors were equally hot. Creeping at idle felt labored, so I pulled into a service bay of a customer of mine's shop. The rear differential was very very hot to the touch. I pulled the fill plug to have 3-4 ozs of very hot, very burnt smelling gear lube come out.
To make a painful story short, I have the car on ramps right now and I don't see a logical means of remoiving the rear differential. Anybody have a manual? Should I buy one? I'm good enough with tools that the Volvo is sitting outside of the project garage while one of the lucky BMWs gets an updated motor and suspension and paint and...

Car has 86K and religious maintenance.

Any prior victims tell me what a rebuilt pig costs? What is wrong with my pig and is it terminal?
Thanks-
Demian Trubey
trubey@ameritech.net

You have to drop the comnplete rear subframe with the gas tank to remove the rear diff BUT why exactly do you want to do that? Just because it got hot and smells burnt?
A main problem with Volvos older AWD system (not Haldex) is that there's more power robbing and heat buildup in the units than there should be so both front angle gear (bevel gear) assemblies and rear diffs can get hotter than they should and as the fluid expands, it'll spew out the vents. Diff fluid usually smells burnt btw.
If you have mismatched tires, you'll damage one or another costly AWD part as reported here many times before.
If the rear diff isn't noisy, I wouldn't consider replacing it. Now......if you want that car to go fast and don't REALLY need AWD, remove the driveshaft from the angle gear to the rear diff and see if the rear diff still has overheating problems (probably not) and it'll drive normally except not AWD, just FWD.
The rear diff in the car is a pain to replace and costly so I wouldn't advise replacing it yourself unless you have no other choices. It'll require a hoist and trans jack with an attachment to support the gas tank and rear subframe assembly all at the same time, not a job for someone w/o experience IMHO.

It started humming. Either way, I'm going to have to remove it. I couldn't tell how the axle shafts were removed. I was actually considering turning my R into a T5 temporarily. But with the noisy diff, I'm going to have to remove the axles if I do that. I have no clue how they come out. The front differential is limited slip?

Anuybody know who makes the "older" awd system? I believe I'm going to need a new rear diff. $3725 the volvo sdealer wants seems excessive to me.
Thanks.
Demian

The front diff is in the trans and is the exact same one used for the 2WD car.
There's no way that anyone will explain the complete rear diff R&R process here so if you're going to try it, I'd highly advise buying the OEM manual on it from Volvo. Call 800-25-volvo and order TP 4314201 (V70 AWD manual) and after you read what's involved, then you can decide if you really want to try that. No one but Volvo uses that rear diff so I'm sorry to say that you don't have options with that unit BUT I'd still try removing the front to rear driveshaft just to see if that helps as it can't hurt.