buuzy

Got a favor to ask you guys out there. While cruising, my transmission shifts hard everytime I take my foot off the gas and then step on it again. Is this normal for a luxury sedan (mine is a '96 SC400)? It's been doing this since I got the car 4 months ago. I just want to make sure if it's something wrong that I get it fixed before it becomes a bigger problem.

Keith13b

iTrader: (3)

Mine does it too. I thought it was a problem untill others complained about it as well.

It is very annoying to say the least. I plan on changing the tranny fluid in the next month or so. Maybe it will make it a little smoother. Idunno. If you find a solution- please post.

O. L. T.

iTrader: (17)

It is definately not normal. my car has 186k on it with a bad center driveshaft bearing that i am in the process of changing and it STILL doesn't do that. These trannies are so unbelieveably smooth you can sit a cup of burning hot coffee in your lap and drive normal without spilling a drop. my tranny has never performed anything aside of excellent in every way, and it has to be the best shifting tranny of any car company. sounds like you need to check for worn components.

good luck!

VSsc400

iTrader: (1)

this happens to me when I'm going less than 30mph but not at highway cruising speeds.

Carpe Diem

I'd check for slop in the differential and u-joints first. Do you think the tranny shifts or does it just catch hard when you go from coast to accel?

buuzy

Mine catches hard, not the actual shifting from one gear to the next.

SC300Es

Some of us discussed this a while back

https://www.clublexus.com/forums/sho...threadid=89246

Ed

Keith13b

iTrader: (3)

Exactly. Its just a "clunk" feel as second gear locks and it only happens when you quickly let off the gas then apply a very light gas to it. My car has done it since I bought it almost six years ago. Shifts smooth as a baby's @ss anytime else. Its just that second gear after backing off the gas and getting back on it lightly........doesn't happen at any other speed, except granny speed. Personally I think the rpm's of the tranny are still dropping when you go back to engage it, it grabs.

Lets put it this way....I'm not too concerned about it, and was told by a Lexus mechanic that its a "common complaint."

Frankinaustin

I just upgraded to a 96sc4 from an older 93sc4. It seems to me that I experience the same situation. Back when I waisted my money on a 2000 F150, I had a similar prob. I researched and found what was happening is the tranmission's valve body and the ECU's "transmission control tables" weren't working perfectly together and the Torque Converter Clutch Apply valve was opening and closing harshly at the wrong time. (this affected the lock up of the tranny's TC) A Ford tranny rebuilder called Baumann Engineering had a $25 remedy that looked like a teeny weeny 10mm aluminum piston and spring. It installed DEEP into the valve body and supposedly would fix the prob.

I never did the upgrade b/c I sold my truck, paid off the loan and bought my 93SC400.

Now that I have a 96SC400 one of the first things I noticed is the nice thoughtful Lexus engineers added some transmission crap into the ECU - i.e., it retards the timing between shifts to make it all smooth.

Now I'm no expert, but the probs ya'll discribed sound like my old ford tranny. Perhaps the lexus enginners made some changes into the ECU for tranny control, but didn't do an impact study on how it affected low speed driving. Just a thought...

lexsoarer400

I had the same thing up until last yesterday . . .the only difference in what was wrong with my car was that the check engine light was on and i was getting a code 13 (RPM signal). The problem was a bad cam sensor. I got it fixed and the car feels 1000 times better. i also think the car runs a little slower when the check engine light is on but either way my shifts are way better and feel smooth off the line and in all gears.