Im getting a weird grinding/vibration right under the driver side floor panel. So my feet. At 70+ mph. Everything is smooth as butter until 68ish and then its really bad at 70.

I tightened the front ds up at the axle, one strap was a tad loose. And it helped a little bit. But it is still very noticeable. Everything else appears to be fine. My whole front end is new.

Kinda lost at this point. Need ideas.

 

snap ring in the t-case still in place? fluid level up to snuff?

 

Could the snap ring really cause a vibration all the way up to the front?

Come to think of it, it could be the cause. Because i dont have a front cad my front ds is always spinning, so therefore the tcase is too. Albeit in neutral.

I will check that. But I have a 241 sitting in my garage waiting to be rebuilt

 

Vibrations/noises can be funny...... Just because you hear it from one location, does NOT imply that is where it is actually coming from.... This was recently driven home quite beautifully by my Astro AWD van..... I heard a HELLACIOUS noise coming from the 'front', to the point I thought the front diff was thinking about falling out...... noise would change on corners, so, I thought, "Wheel bearing", and replaced the one I though it was. Taking it off, the bearing felt fine. Put the new one on anyway..... Took the van for a drive, no change..... Couldn't afford a diff at the time, so, just took it off the road. Fast forward three months..... needed to move the van, went to air up a REAR tire that had gone soft, and noticed ALL the lug nuts were loose...... (at this point, I started thinkin' I was going to need to feel stupid....) Tightened 'em up, aired up the tire, took it for a ride..... Noise was gone. Van drive quite nice..... Then I felt stupid.

 

Haven't checked snap ring but topped off fluid. It was a good 1/4-1/2 quart low

Vibration/grinding still there.

Removed front ds.

Still there. But more mild and at 75 mph. Changing lanes at speed while it was mild vibration caused a massive increase in noise/grinding. Once wheels were straight it went back to mild.


Thoughts? Could it be alignment? Bad tires, even though they are new?

U joints all seemed nice and tight. They are new. Greased them and the double joint up while it was out.

 

Are you sure it's the t-case? Sounds like a wheel bearing, given that it changes when you turn.....

Got a posi rear? Might be that too....

 

I'm thinking it's not the t case now.

Driver side wheel bearing is new. Passenger is not. I torqued nuts to spec.

I have a limited slip rear. Not sure how that could be effecting though?

I have had bad wheek bearings before but they all groaned at low speeds turning. Could still be that though.

 

When was the last time the fluid was changed in the rear? Might try just adding some friction modifier, and see if that makes any difference. It's a cheap test. (if it is in rough shape, it growls, gets worse when rear wheels are going different speeds, like when you are turning.)

 

I'll give that a try. Might just take the cover off and see what's up. Been meaning to change the fluid

 

Well took the cover off. Here it is.

I don't see any metal pieces floating around. The magnet ont he diff cover is pretty covered though.

The fluid was awfully black. Is it supposed to be? First time tearing into a diff. I took it off after driving home 30 miles. It was pretty thin too. I expected it to be thicker.

Going out now to refill with limited slip addivite and standard 80-90