Classic sign of torque converter not initially having enough fluid.

 

I measured the Voltages as follows:

1) At night after driving long time
Engine On : 13.43V Engine Off : 12.71V

2) In the morning after idle for long time (10+ hrs)
Engine Off : 12.46V Engine On : 14.47V

The problem still exist this morning so car is still stuck for a while.


I am thinking of cleaning the transmission like you said. By flushing do you recommend those lube station flush using a pressurised machine?

 

In this case should I just add more fluid or something need to be replaced?

 

If there is rtv sealant in the transmission you need to remove the pan, clean out all the junk, and flush the system out. If you notice sealant all around the outside of the pan there is probably a lot more on the inside. Anyway, go talk to a professional mechanic and tell him about what you have been instructed here.

 

A garage technician nearby suggested to rebuild the transmission. He think that it is nothing to do with clean the transmission nor the seal. However he didn't check the car yet.

Would like to listen to you guys opinion before going ahead.

 

Just tried to flush the transmission, clean the pan, remove the seal, by a professional mechanics. It seems the situation is getting much better for few days, going forward no stuck after long parking. But reverse is very difficult and need to ramp up the engine before it can engage to reverse.

Does this improvement provide any hints to the problem?

 

Did the mechanics say there was sealant inside the pan? I don't know what to say to you. If there is still remnants of the rtv inside parts of the transmission then it will still affect it as you are experiencing. Did they actually power flush the system or just drop the pan and refill? I would never normally recommend power flush unless it is a situation like yours.

 

He didn't mentioned. What he did is remove the pan, clean it, and flush it with transmission fluid, but not the power flush.

He said he don't know what happened, but just mentioned transmission rebuilt can solve everything related to transmission.

We hardly able to find real mechanics here.

 

I think this is very important detail of information you need to find out. I agree that to rebuild of course will fix it but the cost is a lot more and maybe unnecessary. I would find out if he did in fact find rtv sealant inside the pan and in the fluid. If so, then you at least know what is causing the problem. Also, how did he seal the transmission pan? With rtv or a machine made gasket? A power flush will push new fluid through the whole system and potentially get out any of the rtv that is stuck inside. When you drop the pan you only get about 1/4 of all the fluid.

 

I would stop driving it until you get the slipping figured out. You can damage your transmission more if it isnt already toast.

I would try draining and replacing the fluid multiple times in short intervals. Make sure you buy the correct fluid and don't put any stop slip additives in the fluid.

HK = Hong Kong, If so do you have Lexus dealerships there? If you don't do the transmission service (drain and refill) yourself I would take it to the Lexus dealership.

 

Has your fuel economy decreased???

You also might want to try warming up the transmission fluid in neutral instead of park and let us know if that makes any difference.

 

I have driven very long distance since this problem. It seems once it gear engaged it is silky smooth, it won't slip at all during drive.

Yes, in Hong Kong, car like this are considered old, the 2nd hand price as low as USD$3000. So most garage is not willing to do or even learn any fix. Lexus dealership would like to quote you a very high price for repair in order to get you to buy a new car.

But I still believe the problem doesnt appears to be a serious one that need a complete rebuild. Also a complete removal of the tranny may also cause other problem if handled by un-professional.

The fuel economy is fine and the car is so good that I want to keep driving it. There seems hard to find a good replacement for the LS430. My very young daughter say when she get on this car for the first time "Oh, this is comfortable....."


Warming up in Neutral does it difference from Park? Let me try it tomorrow morning. Would tell you the result.

Now the problem is reduced to "Unable to go into Reverse in the morning after parking for long time". Going forward is fine.

 

Lexus LS430 for $3000USD? I've never been to Hong Kong but in Japan it is the same way, few drive older cars so the used car market is saturated with great deals.

If that is the case then I'd keep it for parts and buy another one with a good transmission if multiple drain and refills don't fix your issue.

Rebuilding that transmission in the US is going to cost more than $3000.

I agree with what has already been said, your fluid level is probably low or you don't have the correct fluid.