I have noticed that when accelerating from a stop, that when my car hits 15 mph I feel this ever so slight rumble strip effect. Many people would not even notice it. It only happens, that I can tell,
at 15 mph. It does not happen every time. I have changed the differential fluid. It seemed to get better but it hasn't gone away. My ATF gets changed regularly with WS and only has 15K on it.

An old mechanic replaced the hanger bearing in my old driveshaft and did not mark the pieces. He put it in wrong. Obviously.

I ended up with a tremendous vibration and since no one balances Toyota/Lexus driveshafts, I went and got a used one and replaced it.

Where would you start looking? It only happens at 15 mph when starting from a dead stop. AND it doesn't happen all the time.

 

I would think tire or wheel imbalance might be an issue, producing a resonance in the steering or suspension at that speed.

 

It could be your transmission control module. Test if the two speed sequential mode makes any difference.

 

I ain’t as bright as you give me credit for. What is the “two speed sequential mode”?

or are you just pulling my leg?

 

check on your transmission gearbox if you can select +S- mode (usually by pulling the shifter to the left). Then with up and down direction you may switch in between 1-6 gears. By choosing 2, you will activate only first two gears to work. See if this mode will fix your issue.

 

Gotcha. I thought you may have been talking about the "Snow" and "Power" mode.

I'm a little afraid to ask this but what if it doesn't shudder when I do this?

I will add more information that may help. I have noticed when I brake the AT downshifts quickly and it seems it stays there a little longer than I would like. Totally subjective. But I do notice it.

I have a 1998 LS400 and a 2007 GX470 that do not shift this way.

 

The flange ends of the driveshaft are aligned 180 degrees to each other (not aligned tip to tip)..only 3 possible orientations....

Possibly the used driveshaft U-joint? Unless you extracted the shaft, it might have been wrenched or separated.

Guibos replaced?

Did the shop reuse the factory shims between center bearing and chassis..or did they lose them?

Driveshaft angles checked?
Shims also used at rear differential.

With great difficulty and over 4 months time. my 1999 LS400 driveshaft was balanced..
Special fixturing had to be fabricated:
​Same guibos and flanges on 1998-2000 LS400 and 2001-2006 LS430.

The shop is in Ohio.

Post:

https://www.clublexus.com/forums/ls-...omponents.html

Since you have your original driveshaft, you can have it balanced...

 

Thanks, YODAONE!

Do you happen to have the drive angle specs for a 2005 LS430? I don't really want to purchase the factory manual.
I'm almost broke from all I have already spent.

I'm gonna contact B&T Driveshaft.

 

Lexus can probably provide you with that chapter from the shop manual. .PDF

Explain to the Lexus parts guy you need it before you can order shims...