My 1997 LS400 has an issue I have not seen in any of the other threads. When the car is cold it will not go into D,3,2 or L. It does go into R. It acts like it goes into gear with a sound and feeling of engaging. If I start when cold the rpms are at 1500. As it warms it goes to 1000 then stabilizes at 750-800. This usually takes 6 min. At this time the transmission will go into any gear and drives fine. Fluid and filter(lexus) was changed 3 months ago. level is fine. I did trouble shooting and when doing the manual test, it does not go into gear with the connector off when it is cold. it does go into R. It does go into gear when it is warmed up, which the manual says to bring to operating temps before the test. The hydraulic pressure is 0 in D when it is cold. When it is warm, it is right within the limits.
It says that there is an internal leak or first gear clutch is bad. I suspect leaking seals but still cant figure why its fine after being warm. wondering if I need a rebuild or if there is another option.

 

please try this experiment, and I think you will be quite surprised - it is safe, my friend Paul who is an engineer for Aisin (who designed and built your transmission) suggested it:

add 3/4 of a quart of genuine Toyota T-IV to the transmission, and if it isn't fixed, add the last 1/4 of a quart

 

Thanks for the quick response. I will give it a try in the morning and lets see what happens!
Can you explain the theory behind this?

 

OK. Yesterday I added 3/4 of T-IV. No change. I added the last 1/4 and the car went into D. It did not go in at cold idle 1500rpm. It took about 3 min to idle down to 1200 and went into D. Better than waiting 7min and idle at 800rpm. I did not drive the car.
Today I started the car and it did not go into gear until 1200 rpm. The shift into D was hard, maybe due to the 1200rpm. I turned it off and came back 1hr later and it would not go into D. I let it warm and idle to 800rpm and still no D. After 15 min of shifting in and out of D it finally went into D. I drove it for 45 min but check engine light came on. Still rode normal. getting codes in a few. Maybe for high trans oil level?
It will work fine if I warm up at first start of the day and drive it for a while. It will go into D anytime after that initial ride. Once it cools down, we start all over again. If I dont wait till 800rpm it will not go into D until it is ready to, no matter what the rpm is. Like I changed the sequence on it or something because I didnt wait for the 800 rpm. What does this show you by adding the extra fluid?

 

I'm not sure you are the only one having this strange issue, as mine was quite similar. If you take a look here and start reading from post #23. It might not be the same issue, but seems to me you are doing exact same things with similar effects. In my case I added cleaned the pan and filter, added fluid and everything went to normal for a couple of weeks when it actually went as bad as it should. My advice would be to stop driving the car as it might get only worse and check according to the manual if it is not the forward clutch going bad.

 

Xaper,
Thanks for the reply. I have seen that thread. LSCOWBOY made some suggestions and I am waiting to see what he thinks about the results.

My check engine code was P 0125 insufficient coolant temp for closed loop fuel control. My reservoir was low. I will fix that in a bit. I dont know if that effects the tranny going into D.

 

I am having this exact issue. 1994 w/ 230k. First start up in the AM does not want to go into forward gears... Seems to be temp related.. the colder it is the worse it gets. Literally just pulled the trans pan and cleaned the filter. Considered pulling the solenoids off and cleaning them as well but after I get the pan off I changed my mind lol. Anyway 6qts of T IV fluid and it still did it. Though I tried with only 3 first since I thought that was the drain and fill amount. I kept adding one more at a time and the issue got better. Now it's hot and took all 6 qts I bought(was hoping to change it again next weekend to get more fresh fluid) but I can't tell u till morning if it's any better..

I also did some of the tests from the manual.

WOT & brake. Reverse and drive was 1900-2000 rpm.

N-D and N-R shift times are both less than 1second, with reverse being slightly longer.

 

have you dumped the ECU diagnostic codes? (that link is for 90-94 owners, for 95 and up, just have any auto parts store scan and print out the codes)

on both generations, this problem is often failing ECU capacitors - you can perform Yamae's ripple test below or else pull the ECU and photograph it and post the photos here and the problem is often visual in the form of a corrosive electrolyte leak

for something cheap and easy to try in the meantime, I would replace the $50 Engine Coolant Temp sensor with the genuine Toyota part, and do Yamae's ECU ripple test or else take the photos above.

 

Sorry, been away a few days. The adding fluid trick only worked once, then back to usual issue. I attached pics of the ECU but didn't see anything obvious. I will put ecu back in and try ripple test. I will also order the Engine Coolant Temp Sensor. I will just wait till she warms up to get it into D for now. Let me know if you see anything on the ECU.
Thanks

 

If your ECU is still out. look under the capacitors for a slimy clear fluid. You don't want this to touch the PCB because it is caustic, that is a subtle leakage and can be significant as more of the fluid leaks out. Mine was beginning to show a slight hesitation when selecting <R>.

 

yes, I see someone has rebuilt this ECU using the wrong type of capacitors (as usual)

 

OK. I found the previous owners maintenance records and it shows ECU replaced in 2011.
I guess I should change the caps.
Will the ripple test let me know if changing the caps will fix my issue?
I have replaced resistors on a TV circuit board before with success, should I give this a shot or find someone local to install when I order the recommended caps?
I have no signs of leakage on these caps.

 

the problem with these particular caps is not leakage, but rather being the incorrect type

 

Having my transmission rebuilt, and went into the shop today and asked if he'd found the problem. The very experienced transmission mechanic showed me a cracked piston forward drive/clutch part. "This was a common problem on these transmissions" he said, pointing out the cracked metal part. "They later added a reinforcement to prevent this from happening, and I'm searching for that part now." It's going to take some time to get the right parts in to fix, but he'll get it done.