I am new here, so this might be an oft repeated question. I have a 1998 GS400 with 47k miles. I've owned it for about 7k miles (all in warm weather). Recently, with the cold weather, the transmission will occasionally (maybe twice every 75 miles of driving) downshift in a harsh way. Also, when it is real cold it tends to hang in 1st gear a bit long on the upshift as well. I can't tell if:

1. it is due to my driving style and this is maybe an adaptive transmission? I am never sure if just before it happened I was driving aggressively...because I wasn't expecting it to happen!
2. this is common in the cold weather and this is just such a well built transmission that it acts like a manual sometimes.
3. this is a common problem easily fixed cheaply
4. I am screwed.

If I'm screwed, what is the cost of a rebuild?

Thanks,

Bryan

 

ummm for me if it's cold then yes it shifts a bit harder but it's not unbearable, plus after the first shifting then it's all good. the harsh down shift i am not sure though.

did you try to get a lexus tech to test drive with you and see what's up?

 

Mine when cold shifts very hard under full throttle it also will shift early. I think the tranny does this to keep you from reving the motor to hgih when it is cold. Mine also kicks down very hard at times when i go from cruising to flooring it.

 

mine downshifts if I am on a downgrade..and I get similar issues, almost feels like it is slipping on stop and go when its cold..took it to lexus..tech told me the downshift was on the down slope was normal..and said he couldn't feel anything wrong with it...I am debating on getting an extended warranty just so I feel better...anybody have any experience with them?

 

Add Lucus transmission fix to your atf. It works. The shifts in my 98 gs400 is noticebly smoother with no notchiness.

 

i concur

try Lucas trans fix

cost around $10

definitley notice the improvement s

shocker did you add the whole thing ??

 

Yup, I did add the whole 24 ounce bottle. no harm done to tranny if u add to existing tranny fluid. Note: Keep the engine running when you add it. the engine heat and tranny heat will allow the fliud to flow easily down the tranny spout.