I have a 2002 F150 4wd. I've been having a shudder on takeoff in turns mostly the right side. After looking through the forum seeing several others with similar issues were able to eliminate or post pone the clutch pack replacement with a fluid change I decided to attempt that. Well come to find out my right side bearing crapped out and has worn a nice groove in the axle shaft. When I got the info off my diff tag (9.75 V919B) and went to my local auto store the bearing and seal aren't the right ones but the 8.8 bearing and seal fit perfectly. Got an 8.8 shaft and it is a 31 spline and I need a 34 spline. Am I stupid or am I missing something?

 

Well for one, if you do indeed have a bad bearing, generally, if driving, youll hear a light whine/whistling sound. I did in my friends GM 10 bolt when his carrier bearing went out. he had the whine that you could kinda hear. anyway, 1st check your door jam for axle code then hop back on here and find out exactly which rear end you got. secondly, if it is the bearing then that needs replacing. and do you have any pics of your gears and of the "bad" bearing. Im no genuis but some of the guys on here are, and pictures help. we can see what you do. thirdly, did you drain and fill your diff with friction modifier, close it up and drive it around to see if the shutter went away?

 

Ok little more detail. I opened the rear end and the fluid was almost black and very sparkly(metal in oil). I started looking for other issues and found radial play in the right wheel. Pulled that shaft out and found a groove worn in the shaft. Checked bearings and found them to be worn. Ordered a new shaft seal and bearing. All were wrong for what is installed on truck. Although they were Correct for what I found on rear differential tag L55 9.75 V919B and on door post axle H9. Talking to mechanic and looking at parts I removed determined the seal and bearing I needed were from an 8.8 rear end. Got bearing and seal installed went to put in shaft and couldn't. Pulled new shaft out and counted splines on new and old shafts. New shaft has 31 and old shaft has 34. Has anyone else had this problem does anyone have an idea of where to get a new shaft?

 

They new shaft they sent you is for a 8.8. 2001.5+ used a bigger bearing than previous 9.75's. You need a new axle for a 9.75. All 9.75's are 34 spline.

 

You could always just use that old shaft again and get a Timken Repair Bearing for it. I believe yours should be the TRP1559TV part number.

What it does is put the bearing inboard a bit, and allows the new bearing to make contact with a new surface.

Just an idea....

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EDIT: If you are interested in this alternate solution, here's a link. I thought I would also mention that this unit has a seal built in to it, so no need for an additional seal.