I have a 1998 F-150 Lariat 4x4 automatic. when I'm driving I get a noise like it has mud tires in the rear. The Noise is more pronouced when accelerating. It is noticeable at all speeds over 20mph. What could this be? Please help!

 

Hey, I have the same thing going on with mine, I think mine is the pinion bearing going out or has already gone out. So this week I ordered new gears and install kit for it and will send it to the shop next week for replacement.

I have 3.55 in it now and I was going to go for 4.10's but after I purchased my Edge Evo. and programmed the truck with it. I think the 4.10's would have been to big, so I'm just going with a 3.73. Since its in between of the two I think its a good place for me and my driving habits. Any I will let you know next week

 

Hey thanks Markus...mine is also a 3.55 L 8.8. I have done a little research on differential noises and have read the 8.8 pinion bolt is notorious for backing off on these rear ends allowing slop in the bearing loads. How ever I have noticed that the noise in mine changes ever so slightly when I turn right or left causing me to think the carrier bearings may be coming into play here also. I'm thinking of doing a self rebuild. Let me know what your shop finds out during the rebuild.
Many Thanks

 

i'm not too sure about the diff, but i just replaced the carrier bearing in my 95 302 auto. it cost me enough that i'd have done it on my own if i had the time and space. i ended up having to replace the rear u-joint two days later. smooth as silk now

 

Sounds like a typical rear diff bearing problem. Which one? Can't say without hearing it. But, the best fix is to replace all the diff bearings at one time due to metal contamination.

 

Markus21,

I think that you should go up to 4.10. It really puts the power to the wheels.

5150

 

Well if I lived in the City I probably would have went with the 410's but since I drive about 25 miles a day on the highway, I think that the 373's is a better choice for me.

By the way I just had the new gears put in "373's" and it is so much better! I'm still breaking them in, so it will be awhile before I can really test them out. But let me tell you with the Edge Evo and my new gears the truck seems like its brand new, the combination really made a big improvement.

With the new gear install, all I did was drop the entire differental and take it to the shop, it took about 4 hours total, thats taking it out and re-installing it. And it only cost about $360 ! compared to the stealership which wanted $1,500.00. Very easy project

 

I had the same problem and it was the pinion bearings. Swapped them out and its cool now.

 

Thanks everyone, I guess I will get under it myself and drain the fluid and remove the cover and do a little inspection to see whats going on with it...these shops around here are way too high. If I have to change the Ring & Pinion + bearings I have done my home work and it does'nt sound like it will be too bad of a job except setting the pinion depth. I'll let everyone know what I find and ponder your suggestions...again Thanks