Strange Whine

[leftoverture]

OK...just when I think I got the Ex all fixed up....

A couple times since I got the truck, I have taken off and had a whine that sounds like it's coming from the rear end. The first two times this happened, and they were at least 700 miles apart, the whine stopped the first time I stopped at a stop sign and started out again.

Today, however, when I took the truck to lunch it was whining all the way to the restaurant (about 4 miles) whether I stopped or not. Even after having lunch, it whined all the way back to work. Then...after work...no whine at all. This third time is about 1000 miles after the first two times.

I haven't checked the diff or transfer case fluids yet but just wondering if anyone else has experienced anything similar. It is a 4WD truck but this happens in two wheel drive mode. I haven't really used 4WD yet.

Thoughts?

 

[Anime]

The Ford 8.8 actually whines due to it's design, but the Explorer axle is supposed to be equipped with a large round weight, which is bolted to the passenger side of the rear differential, towards the front, which helps to muffle the whine. If yours is missing this weight, that could be what's causing it.

If it has the weight attached to the axle, you should probably change the gear oil ASAP. Get some 80W-90 Gear oil (75W-90 synthetic is even better, or use 75W-140 if towing heavy loads) and sealant for the cover, and change it out soon.

 

[leftoverture]

Well I was thinking about this. When I went to lunch and had the whine, I only drove forward. I mean even when I parked, it was a pull thru spot. But back at work I backed into my parking spot so maybe the backing up caused the whine to stop. So would that mean any thing if backing up stops it? This was in 2WD mode so the auto hubs shouldn't have been engaged and the sound didn't seem to come from the front.

 

[Anime]

It's probably something to do with the rear drivetrain, the front axle isn't engaged at all except in 4WD.

You might also want to check the transfer case fluid (it uses Dex/Merc ATF) and the u-joints on the rear driveshaft. It could also be a wheel bearing.

Backing up probably stops the whine because it causes whatever is making the noise to rotate in the opposite direction, that's all. Gears and things are optimised for forward motion, though they also work in reverse but not as well as they do forward.

I would check it all out ASAP, whatever is causing the noise could be a severe risk and you might wind up losing drivetrain parts because of it. Check those fluid levels and the u-joints ASAP.

 

[Roadrunner777]

Have we ruled out brake issues? Backing up adjusts the shoes.

 

[leftoverture]

Since I haven't checked anything yet, I suppose nothing can be ruled out. I have not looked inside the drums, but I have also not had any grinding noises or anything. Right now I have it parked until I have the time to look at things. It's just weird how it's so intermittent. That could make diagnosing it difficult. I suppose if there's some loose debris in the drum it could be getting caught in the shoe from time to time or something. Check fluids, check brakes. I'm at least developing a list of things to check.

 

[Anime]

You can check the gear oil by taking out the filler plug, which is on the front drivers side of the rear diff. It uses a 3/8" square drive, so just a ratchet extension works. It might be in there solid so you might have to use some penetrating oil/fluid to have a shot at getting it out. Stick your finger in the hole and check the level. If it's well below the bottom of the filler hole (spec is 1/4" below the bottom) then the fluid is low. If it's gritty then it really needs to be changed.

I'd say since you don't know what fluid is in there or if it's EVER been changed (most of the time, it never is), it's better to just spend the money and put new synthetic gear oil in.

The U-joints and diff pinion/transfer case seals can be checked with just a flashlight.

Wouldn't hurt to pull the drums and check the condition of things, though I don't know if whine could be contributed to brakes, unless it's some other sound.

 

[leftoverture]

Whine. Groan. I don't know how to describe it. It's not a grinding. But I think it could be debris in the drum getting caught up between the shoe and the drum. Maybe. Gonna try and check it out this weekend, but I have been so busy lately.