My '02 F-350 4x4 CC 6 speed has 75,000 miles on it and for the last 6 months, I have been hearing a noticeable whirling/whining noise, similar to tire noise, at speeds between 25 and 45 mph.
I rotated the fairly new tires with no change in the noise.
I had a (1) bad U joint at the differential , so I had that replaced last week. All the other joints and the bearing between the two driveshafts are fine.
Replacing the joint made no difference in the whiining noise.
I took it to a mechanic that I use occasionally. He is a straight shooter and I have known him for 15 years.
He took it out for about an hour and is convinced that the noise is coming from the transmission.
In his opinion, it is not worth tearing into the box to investigate. He is thinking it is gear noise that is becoming more noticeable as the truck is getting older.
I was thinking of changing the fluid as a starting point, since it has not been done yet.
Any one else experience this?
Any ideas or suggestions?
Thanks for any help.
Scott

 

Before you blame the transmission, check your needle bearings in your front hubs.

ZF 6 speeds are pretty good units. You don't see a lot of failures with them. I would suspect a noisey throwout bearing first. If you are sure it's the transmission, you might see if a fluid change helps.

 

I had the same problem for a year and couldnt find it...turns out I had a front wheel bearing out. I was told it is a common problem, but no one on here knew anything about it.

I found mine by removing the front tires and spinning the hub with the brake calipers off.

I was convinced it was in my tranny also, replaced hub assembly and now is quiet.

 

 

Does the noise go away if you shift down to 4th?

 

Does it do this more when hot or cold?

Definitely check your fluid, the radiator can fail and you can get coolant in the transmission then weird **** starts to happen. It will look like milky diahhrea vs. red ATF. If this happened get that radiator replaced and the fluid flushed out ASAP.

 

Change the fluid and use recline MTL or Pennzoil sychromesh. Don't bother with the fill plug, drain it then take the shifter off of the top and dump 7 quarts in.

 

This is terrible advice.

It's way less work to just use the fill port. That is what it's there for. Plus it's more wear and tear the expensive shift boots that actually keep quite a bit of engine noise out.

 

No it's not, I fill all manual transmissions that way, much easier than laying on you back trying to get it in the full plug without spilling it everywhere, and it allows you to put an extra quart in which helps quiet the gear rollover noise. It's 4 screws and 6 bolts to remove the shifter not hard at all.