I have a noise that is really troubling me. It is almost like a noise made by an aggressive tread tire running on the road... only the noise only happens at around 30-40 mph and only when I am on the throttle. The noise goes away as soon as I let off the throttle. It is especially loud when I am lightly pressing the throttle and if i am very light it is almost a pulsing noise.

I recently had a new custom driveshaft put in after it almost blew up on me. Front diff fluid is good. Transfer case fluid just replaced with 85w-140. also discovered grey diff fluid in the rear. drained it, flushed it with clean oil, then drained and refilled it with 85w-140.

I do appear to have a front axle oil seal leak but its not draining a lot of oil at the moment. I also have grease or oil on the housing that contains the pinion oil seal (not sure what to call that portion of the diff).

Any advice or suggestions? My shop can't see me until the 20th and this is my daily driver. I am handy with a wrench, but I am a grad student and only have a bottle jack and gravel driveway to work with haha.

 

I'd slide underneath and make sure the driveshaft bolts are tight. If they are okay, jack up each wheel and check wheel bearings.

Brian.

 

Would a wheel bearing stop making noise when I let off the throttle? It's almost like the noise is controlled by load in the driveline. I will definitely check those bolts tomorrow and I suppose I never checked the rear wheel bearings. Haven't heard increased noise when cornering, but I suppose they are worth checking. Thanks!

I also want to check the pinion bearing and the front output shaft on the T Case. I am wondering if the vibration from the bad front drive shaft threw those outta-whack. I suppose an important note is that this noise is new ever since the drive shaft went about a month ago. Thoughts??

 

Pinion bearing in the differential probably on its way out....
try to figure out if noise is from the front more or the rear.
I found a website that sells them re-manned at a decent price.
http://store.toddcosuspensions.com/larotrcage.html

 

If the pinion bearing is bad, does that mean I need a new diff? Or is that something that can be replaced easily?

 

The entire differential assembly can be pulled pretty easily. I did mine on my own (rear, not front) in a couple of hours. Good used replacements aren't very expensive.

 

unless you have the know how and special tools, I would recommend getting a used/ re-built differential and swapping it out...

 

Around me this can be bought for about $30-$50.