Hello! I was wondering what a whirring sound was in my 1983 GL wagon. It only happens when I shift into my 4WD. It usually happens when I hit about 20mph. Earlier today I was in my auto class, trying to diagnose the sound and vibration. I found my drain plug and eventually read on another forum that the trans and t-case use the same fluid. The fluid was a honey color, my instructor said "This is so clean, I'd put it on my pancakes,". The drivetrain is actually not very used, I only have about 87,000 mi on the car. I know it couldn't be a bearing because it only happens in 4WD and I'm hoping its not too serious because the bottom of the wagon is rusting away and any major part installment would be a waste. Any help or knowledge corrections would be awesome, thanks.

4WD should only be used on loose stuff, snow ice sand mud gravel.  Using it on dry pavement causes binding in the system.

Also, all 4 tires need to be the same Brand, type and size.

 

That said, I would check the u-joints on the driveshaft, and check the joints on the rear axle shafts looking for any play.

 

How's the gear lube in the rear diff?

 

Everything from the rear tires up to the trans is just along for the ride when you're in FWD, no load against anything. So a bad u-joint could basically hide itself until you shift into 4WD, same with rear axle joints.

 

Just some thoughts on it.

 

And Welcome to the Board!

4WD should only be used on loose stuff, snow ice sand mud gravel.  Using it on dry pavement causes binding in the system.

Also, all 4 tires need to be the same Brand, type and size.

 

That said, I would check the u-joints on the driveshaft, and check the joints on the rear axle shafts looking for any play.

 

How's the gear lube in the rear diff?

 

Everything from the rear tires up to the trans is just along for the ride when you're in FWD, no load against anything. So a bad u-joint could basically hide itself until you shift into 4WD, same with rear axle joints.

 

Just some thoughts on it.

 

And Welcome to the Board!

All four of the tires are the same. I'll check the u-joints on Monday when I have a lift. Is there any way to check the rear diff fluid without draining it completely, or do I just have to tough it out? 

 

And by "along for the ride" do you mean it's a dead axle, like the driveshaft and diff are stationary? 

 

Also, thanks, glad to see a quick response on something even Google couldn't find.

The rear driveline is still spinning in fwd. There is no load on it.

Remove the upper plug on the diff to check level or add oil.

Don't be surprised by how insanely tight the plugs are.

Yeah, as DaveT said, those plugs can a bear to break loose.

 

Main concern there is getting the upper one out, that's the "fill plug".

 

If you can't get the lower "drain plug" out, no worries there. Just pop the cover off.

Perma-tex Ultra Grey makes for good seal once everything is cleaned up.

Edited January 24, 201511 yr by TomRhere

I use a piece of plumber's strap wrapped part way around a 1/2" drive breaker bar to fit the recess in the plugs.  About a 3' pipe to extend the handle.  Put a jack under the end, and begin to lift the car.  Bounce on the bumper.