NewSlang

Hello everyone, so I just did a transmission fluid change on my 1998 Lexus ES300 with 50000 miles on the odometer and after doing the job I noticed a consistant problem with shifting at low RPM. To start, I did make a thread a couple of weeks ago about changing my transmission fluid and in that thread I showed that the transmission fluid that was being changed still had a healthy appearance so I was advised to do either a transmission fluid change along with the filter, or a simple drain and fill. I chose the later option as I agreed that the mileage was low and since the fluid looked healthy, my situation didn't warrant the need to change out the filter.

Upon draining the fluid I noticed that I was only able to get about 2 quarts out. So I proceeded to measure and put back exactly two quarts of fluid. After the job I drove around and noticed after checking the fluid level on my dipstick, the fluid level was incredibly low. After around 4-5 fill ups of transmission fluid I ended up adding a total of about 900-1000ml of additional fluid, so I apparently was 1 quart low on fluid, but I don't know how long I have been driving with this amount missing.

Now there are some strange this I've been noticing after doing a simple drain and fill. There appears to be noticeable "hard" shifting when driving during the day, specifically when outside temperatures are around 80 degrees or higher. This rough shifting is expressed by a slight "jerk" or "lurch" forward when going from 1st gear to 2nd gear usually between 1000 to 20000 rpm. I've noticed that when driving at night, or specifically when temperatures are around 72 degrees or lower, this phenomena doesn't occur or at least isn't so noticeable that I anticipate it every time it happens. I believe this slightly rough shift occurred prior to changing and adding the fluid, but wasn't really as noticeable as it is now. What's weird is that after draining 2 quarts of fluid, and replacing it with 2 quarts of brand new fluid, that shifting problem seemingly disappeared, or became unnoticeable. It was only when adding the additional fluid that was missing that this shifting problem became more and more apparent.

Here are some ideas I could come up with as the possible causes, but considering that this is my first ever transmission fluid change, I really have no idea.

1. I've read that sometimes adding new fluid to a transmission could move caked on material from one part of the transmission to another, possibly blocking passages, which could cause problems shifting...

2. Could not changing out the filter/cleaning the pan also result in this odd behavior?

3. Could a bad shift solenoid be the cause?

4. I did make a little bit of a mess the first couple of times adding the fluid through the dipstick entry, possibly getting transmission fluid over some parts in the engine bay, would it be possible for transmission fluid to cause faulty sensor readings if fluid gets on the connection?

Oro

The usual cause of this is a broken engine mount. Check your engine mounts all around. There is very likely nothing at all wrong with the transmission so don't worry yet. Even though the car has only 50k miles, the mounts age with the clock, not just miles.

LeX2K

I've seen this happen when the fluid level is too high. Are you certain you're checking the level correctly? If I recall you ended up adding more fluid than you drained out, maybe you did in fact put too much back in.

NewSlang

I've also noticed that sometimes when going in reverse I feel a thump. I've read that this could be due to a failing engine mounts.

​​​​​​Well I've checked my fluid after adding about 900ml total (4-5 individual times by adding 100-200ml at a time) of additional fluid and driving about 8-25 miles straight before checking each time. At the moment the fluid sits at the end mark of the hot region. I can't take a picture as it is dark where I live but as soon as I can get a hot reading I'll try to snap a photo of the dipstick...

It's weird because I checked the fluid so many times after driving, whether it was 10-15 mins or 30 mins and always on flat ground (or as flat as I can find), and the dipstick always read below hot in until now. So unless the dipstick is giving me false readings I'm sure it's not overfilled. The fact I had to add practically another quart of fluid leads me to believe that I must have been driving a quart low on fluid this entire time, but how is beyond me... All I have ATM are the dipstick readings. Also, when I started my car this morning, I did a "cold check" by going through all the gears going down and back up again, and the dipstick read the fluid was at the end mark of the cold line.

Oro

If you drained the pan and only got 2qts., you were in fact low. It sounds like you have the fluid correctly filled.

NewSlang

I apologize for the quality. Was harder to get a proper angle to see the fluid. These photos were taken after about 7-14 miles of driving.

sdls

What brand and type of trans fluid did you use?

NewSlang

I used Amsoil Signature Series Multi-Vehicle Synthetic ATF, which is Dexron III compatible. This ATF is supposedly one of the best that money can buy.

LeX2K

Those levels look correct to me. It would be very disappointing if that Amsoil was not a good fluid for your car. In a 2-3 weeks I'll be putting in in my ES, different transmission but still the same series and takes the same fluid.

NewSlang

Perhaps it's my engine mounts? I noticed every once in a while when I go into reverse I feel a notable thump. I also notice vibration in the steering wheel at idle, as well as vibration on the gas when accelerating.

Oro

Yes, that's the most common cause of this. See post #2 above.

Hayk

iTrader: (1)

There is an engine mount that has the passenger side CV axle with a carrier bearing - very labor intensive and would require a shop to replace it. That's the most likely cause of the thump. You could check it by removing the passenger wheel and filming it while holding the brake pedal and giving it a little bit of gas in Drive and then Reverse. This way you can observe if the rubber is cracked and/or separated from the metal housing. The other symptoms may also be engine mount related, but I wouldn't jump straight into replacing them. My car had the same vibrations before and after all the engine mounts were replaced. Some vibration in the steering wheel and gas pedal is normal on these older cars.

When you're taking dip stick measurements, is the car in Park and idling?

Replacing only 2 quarts of fluid shouldn't make a difference on the transmission. So whatever it is, it would've happened whether you touched the fluid or not. I used AMSOIL ATF before and it did not cause any negative side effects. I would recommend to do another drain and fill in a week.