I am trying to get my '97 F150 ready for my winter driver as I put my car away for the winter. I have a serious howling noise that needs to be addressed. It gets real loud under acceleration but when I let off it stops. I'm thinking rear diff. Any ideas? I'm not sure what rear I have so that is why I am posting this. I couldn't find the tag. The truck is a '97 F150 Extra cab, 4.6 4wd XLT. Thanks in advance.

 

It's probably an 8.8" rearend with 3.55 or 3.73 gears. Differential noises can be very difficult to pinpoint, but in my experience a howling under acceleration only is because there is not enough preload on the carrier bearings. If that is the issue, you could just buy shims and have somebody reset the preload and shim it out for not too much money. But on a '97 I would get a rebuild kit and have all the bearings and axle seals replaced while I was in there. You'd be looking at around $75 for a master install kit, probably $300 labor unless you know somebody or plan to attempt it on your own, and another $40 for axle bearings and seals. You'll also need fluid and possibly LS additive, so add another $15.

If you just want to have the preload redone, it's around $30 for a minor install kit, same price as above for fluid, and you can probably find somebody to do it for $100 or $150.