91LS400LEX

My friend is experiencing another potential "problem" with her LS400. Between about 35-55 mph, it has a rumbling type vibration that can be felt slightly through the steering wheel. Ive driven the car... its not bad, but where the car is otherwise so smooth, its bothersome. The sound is not loud, but it seems to "drum" in your ears. Also, not sure if its linked, but when the temps are cold out, and the engine is not fully warmed, when the car is in 4th gear and at a lower speed under light acceleration, there is a slight whistling/humming noise coming from the car. My old 90' LS400 had a similiar vibration and it turned out being the tires, so it may be the same case with this car. OR, I was thinking that vibration may be something like an engine or transmission mount?

Lastly, on acceleration from a stop, there is a slight hesitation just after the car starts out. It has a new air filter, so I do not think thats it... I am thinking maybe the throttle body needs to be cleaned?

Any advice appreciated!

I hope I provided enough info... if more details needed to help out, please let me know and I will relay more info if I can.

PureDrifter

iTrader: (10)

tire balance+replace the trans mount anyways, it helps+ its cheap and easy

ewenpg

Possibly a/or few wheel bearing/s. Bit of a tough job.

91LS400LEX

Thanks! Well, hopefully its what Puredrifter said it was. Rather than those costly bearings.

CUMan

I had a "rumbling" sensation under certain circumstances when I first got my 93 LS. It always occurred when the transmission shifted down from lockup while driving up a slight incline. It usually occurred when the speed was about 40 MPH.

The sensation was very similar to that felt when you drive over rumble strips on the road.

The problem stopped when I had my transmission serviced (drain and fill) with Toyota Type IV transmission fluid. That was about 5-6 years ago. The problem never occurred again.

91LS400LEX

Thanks for that info. Now that this has came up, I have noticed that my 91' LS also does this. I am now wondering if that could be my problem? Would be worth a try I guess. My car has 208K. I think that the PO had the tranny fluid changed not too long ago- may have not put the proper type in. I think mine has a slight vibration though even when its not under acceleration.

91LS400LEX

Well, I checked my friends car again and the vibration is felt mostly through the steering wheel between 35-55 mph. Its a fluttery type vibration and it quickly comes and goes about every second. Its like something is "out of round". Its there one second, then gone, back for a second, then gone, etc, etc.

There is no feeling of it through the gear shifter, so can we rule out a transmission mount? As mentioned, my car is actually doing the same thing, but not as pronounced.

I had meant to "rev" the engine to certain RPMs today to see if I could feel the vibration, which I think would suggest motor mounts?

I wonder what the chances are that it could be the driveshaft or even the rear axle?

sonyman

I think my problem is the same as yours, 91LS400LEX. I also have a whistling noise, and hear my vibration as much as I feel it. I already replaced the driveshaft, which helped, but it's still there to a degree. Please let me know if you find the solution, as the dealer tells me it's "something" within the transmission.

91LS400LEX

I replied to your post on LOC. I will report what they tell me. Hopefully its something simple. The service guy I explained it to said it sounded like the transmission mount to him. I hope its not the transmission. It still shifts perfectly and smoothly in all gears, just like my last LS400.