utexas112

1995 LS400

I apologize to anyone who read about this problem in a previous thread ("grinding noise on deceleration") but I feel like I may get a better answer with a more appropriate title.

The problem is intermittent. That is, it occurs, if at all, once in about 3-4 hours of driving. What happens is this: I am coming to a stop, and right about 20 mph, where the transmission downshifts from 3-2-1, it "sticks."

It then feels like I am in a car with a manual transmission and driving in a gear that is too high for the speed. Then, it eventually shifts down into 1st gear but sort of feels a little "jerky." My mechanic suggested eventually opening it up and seeing if there was anything wrong inside.

Before we result to that, I am curious if anyone knows what else might be causing the problem. So far, I have had the transmission flushed and filled with the proper fluid (i bought from a small dealer - he may have changed tranny fluid and replaced it with the wrong type, but there were very few miles driven on the wrong fluid), and I have reset the ECU by disconnecting the battery.

Any help/suggestions are thoroughly appreciated. I know very little about transmissions in general.

Thanks

utexas112

Bumping this post, thanks.

GRAND_LS 4

iTrader: (2)

wasnt there an ECU update for the '95's? Has it been done on yours?

utexas112

I was told that the 95's are not "flashable." I guess, meaning the only way to update the ECU is to replace it. . .

Its really weird, its like the problem will happen and the transmission will be kind of jerky, but after it happens, all is well. Maybe I should try changing the fluid again??

GRAND_LS 4

iTrader: (2)

How old is the current fluid? is it cherry red? any burnt smell to it?

utexas112

I purchased the car from a small dealership approximately 1000 miles ago. There, they did an oil change and apparently a transmission fluid change. The downshift problem was happening very frequently with the fluid.

My mechanic suggested changing the fluid because they suspected they may have used the wrong fluid at the small dealership. Thus, I performed a flush. I have driven about 500 miles since the flush. The problem has been GREATLY reduced, but still occurs about once every time I drive it.

Currently, the fluid is still fresh and pink looking. I don't notice any metal or anything on the stick when I check it.

utexas112

Also, now when I am in drive and the a/c is off, my idle drops to about 400. Just wondering if maybe the problems are related?

A bit of good news, the transmission problem hasn't occurred for about a week. (crossing fingers).

steveski

FYI I have a 95 and like you every now and then I have the same jerk only it is from second to first while coming to a stop. It is kind of like a clunk noise. It happens so infrequently that I haven't worried about it much.

I thought is was because it wasn't warmed up yet, etc. I only use Toyota Type T ATF and have since new. Some shops will use Dexron if they don't know any better. Others will tell you they can use an additive to make Dexron suitable for Toyota ATF - I still don't use it.

Maybe we will get some input from some of the oldtimers here on what it could be.

JPI Racing

I would want to retract that statement! Some of your local Lexus Dealership used Dexron fluids for years. Do you have any testing datas to back this up?
JP Importz

PureDrifter

iTrader: (10)

i think he means that EVERY SINGLE LS400 is supposed to use Toyota T-II and now T-IV in the trans

steveski

That is correct - many shops say you CAN use Dexron with an additive to make it suitable for Toyota Type T IV. I have never used this and will never use it in place of the T IV ATF.

I don't know the additives name but virtually any shop carries it and will offer it.

chubby

my car jerks too =(

Harky

They are probably not related....

The tranny needs the Toyota T-IV fluid to operate properly. I would drain and refill the tranny a couple more times. (You can get 2-3 qts out from the pan drain. The transmission holds 12-13 qts total) Each time you do this, the old fluid that may be bad gets diluted and transmission performance may improve.
But there is no gaurantee that it may not be a transmission control unit or shift valve issue. You might also consider dropping the tranny pan and replacing the filter and checking the magnets for metal bits.
FWIW, these transmissions are pretty trouble free...

The low idle could be a bad idle air valve or an ECU programming issue. Search in this forum for low idle and ECU threads...it's been discussed at length.