AT transmission smoother in the cold?
 

Did a search and couldn’t find any similar symptoms, so any help is appreciated:

I have a 2001 4Runner, AT, 4WD. I am the second owner of the vehicle and it has 120,000 miles on it. I have no maintenance records.

When engine/trans is cold the automatic transmission shifts smoothly from 1st to 2nd, but when it's warm there is a bit of a “thump”.

It is the same story when shifting down from 2nd to 1st. If I'm comming up to a stop light and the engine/trans is still cold it shifts down to first smoothly, if it is warm it often shifts ruff.

All other gears shift up and down extremely smooth regardless of the car being warm or cold.

Also, in the morning when the engine/trans is cold shifting from Reverse to drive is very smooth, but once the car warms up it often makes a “scraping” sound when shifting from Reverse to drive.

I’m planning on having the transmission flushed in the next week. Any other thoughts or things to look for that would cause these symptoms?

Thanks for your time!

That might be a band beginning to go.....tough to say for sure.
Flush would definately be a good start.

If it is a band, would it be ill advised to travel with the transmission as it is?

I'm planning to head up to go snowboarding this weekend (probably 400 miles round trip, 40 miles of mountain driving, no towing or anything)?

I'll start with the flush and go from there.

Thanks for thoughts MTL

I've got an issue with my AT as well. It seems that whenever the tranny fluid is cold that it won't shift into that "overdrive" gear when I'm cruising at 25mph or less. Once I've run the engine a little bit that problem goes away completely.

I read somewhere that Toyota purposely gave the AT a really smooth shift for comfort reasons but that in the long run, the more prolonged movement between the clutch pads will eventually wear down the transmission faster. If your tranny hasn't been worked on by a shop in its entire life, that may be part of your problem. In that same article, the guy had a tranny shop rework the timing of his shifting to be as fast as possible to extend the life of his tranny.

My dad has a 91 4Runner that has never had to have its transmission worked on so it's possible that your tranny has just run its course and is on its way out. If there's the wrong fluid in there, that could also burn out your gears and 2nd gear is usually the first one to go for some reason.

That's my 2 cents. -Ryan

It is that way by design. :great:



>I've got an issue with my AT as well. It seems that whenever the tranny fluid is cold that it won't shift into that "overdrive" gear when I'm cruising at 25mph or less. Once I've run the engine a little bit that problem goes away completely.

It is almost impossible to say if you'd be fine or not. It is one of those things you basically have to find out when it breaks. I would definately do that flush and have them pull the pan to clean the filter screen (it is reusable).

Also the ECU will lock the tranny out of overdrive until the engine reaches a certain temp, so that feature is by design.

i see. Didn't mean to take rdiggidy's fire with my comment.

Your fluid has been cooked before...that harsh shifts and grinding is very poor lubrication...hopfully no damage has been done but any hydraulic actuator (im a hydrualics tech) and the tranny being one that deals with burnt oil or even water in the oil will cause something like this to happen :(

Get it out....