Differential noise when cold

[J. Olenko]

I've developed a noise on my '02 Trac that I am having a hard time locating. It appears to coming from the differential area or somewhere in the drive-train. It appears in the cold mornings after about 5 - 10 mph. It only lasts a little while but then disappears. After another cold start it will do it again. The noise is obviously from something rotating and is a whirring/grindy/clunking noise (sorry to be sop vague on the sound it makers). Now I just got talked into getting the rear diff. rebuilt when I just took it in to get a leaky pinion seal replaced. I also got a new u-joint at the transfer case. Now, it may be coincidence, or may be because of the diff. rebuild, but that noise was never there prior to the rebuild. Now keep in mind it only appears when cold and disappears when warmed up. Any thoughts?

 

[Vic Sorlie]

I'd ask shop what kind of gear lube they put in. Ford specs synthetic 75W-140 for the rear differential.

 

[J. Olenko]

After a quick trip to the place that did the repair initially and after a chat with the owner and a test drive, he concluded that it was the rear u-joint. He replaced the u-joint and took another test drive. The noise was still there. He then concluded that it must be the front drive shaft because there is a CV joint at the shaft where it meets the transfer case and that must be the problem, he thinks. Now he said that item is not rebuildable and therefore another front shaft with cv joint attached will have to be ordered for about $350.00. The problem is he said that he is not entirely sure if that is the problem. Although he said once he takes it he'll know immediately if that is the noise problem. If it isn't, then back to square one. Anyone else with any thoughts particularly about the drive joint cv joint.

 

[Yardsale]

Run, don't walk, from that shop.



Unless it were a defective U-joint, I would always replace all U-joints on a drive shaft (assuming they have the same mileage).



Also, differential rebuild is not a preventative maintenance item. I would not do it simply because I was fixing a leak.



I had the front drive shaft U-joint and CV joint replaced at 135,000 miles when troubleshooting a vibration. They were not the cause.



Remove the front drive shaft and test drive for a couple of days.