hlippy4

Any help would be appreciated.....I have a 1996 LS400 with 74k miles and at around 37-40mph the car starts to mildly vibrate (not before and not after). When the speed limit is around 40 the car vibrates until it gets out of this mph range.

This irritates the hell out of me and it happens about 50% of the time -- the other 50% the car feels smooth as silk and solid as a rock. I maintain it regularly -- i bought it a few years back with 55k and I had the tranny pan removed -- new filter and the fluid changed. I did not have all the fluid sucked out by machine -- just from the pan.

While changing fluids recently I received 2 different stories regarding the tranny fluid -- 1 said it should be power flushed with a machine and the other guy said no help since it has a filter.

Any help would be appreciated...........I can't believe the tranny would have problems like this at 74k miles...........could there be that something which adjusts???????? What to do??

thanks for any help

hlippy4

SharpLS-96

1) You could have a bad 3rd speed band in the transmission and once it shifts into overdrive it's fine.
First, try having all 12 quarts flushed and changed with OEM Toyota Type T-IV fluid and your filter cleaned & checked for any metal particles and see if that makes a difference.

2) It quite possibly could be a differential problem not a transmission one since you getting a serious vibration through the cabin, might want to have that checked out.
Your mechanic should put the car on a Dino machine in order to reproduce the vibration your experiencing at the speed.

3) Might just be your tires that are not properly balanced.

POS

I wouldn't chase transmission issues just yet - expensive and hardly the best first place to start.

Start with tires - get them rebalanced and rotated.

Next, try checking the tranny mount (easy to fix) and see if it's cracked.

Then go to bushings to see their condition.

Tranny stuff would be my last resort.

Shaffer

If you find out what it is, let us know as my 90' LS400 also does this. It starts about about 47-50 MPH and sometimes lasts up to 60 MPH, then it is smooth as silk. It used to only do it in the winter, when it was below 50 degrees outside. It has recently started doing it, even when it is hot outside. It is very annoying. I have new tires. I do not think it is the tires. It seems to shake the entire cabin. It seems as if it is something in the drivetrain. I was told by someone else on another Lexus site that it could be a bad universal joint, but not sure. Any information appreciated. BTW- my car has 229,700 miles.

Lexs400

note what the rpm needle points to at that speed. then with the car in park just press the gas pedal and reach the same rpm level. if you still feel the vibration then it's engine related and not tires or transmission.
good luck.

sniper

iTrader: (4)

Do check out your diff. I thought Lexus was changing my diff fluid when I did tranny flushes because other places do that, turns out they never did it and the oil was as black as could be. When I drained it, the magnet was COVERD in shavings and the axels on the output of the diff were loose. This would of course cause a vibration. Another thing you might want to check out is your fan bracket. Some times the bearing goes out and the van will vibrate at the right speed. When I had that problem, the car would feel very strong and smooth, than at times it would vibrate. Pop the hood and watch it to see any movement. Watch it at all the RPM ranges. Also while you are looking at that, take a look at your crank pulley. Im sure this is very rare but after I finished my fan bracket, I noticed my crank pulley was out of line. Im not sure what it was, I had a Lexus tech take a look and he said it was all nice and tight and so im not sure what you could do to fix that problem.

Shaffer

Thanks. I will check that. It seems to be getting slightly worse at times and it is very annoying, on an otherwise "super smooth" car. Thanks again.

gmcclintoc

I have a 93 Ls 400 and a few weeks ago my car was doing the same thing so I took it to get it alligned and when the machanic raised it he shook the wheels and they were very loose so he told me I had to get the tie rod ends replaced before he could do the alignment so I did and after I did the car stopped vibrating. So I suggest you take the car to a shop and ask for an allignment and see what the will tell you if they say you have to replace your iner tir rod ends thats the cause of your problem. Two tie rod ends will cost you about $400-$500 for both.