98 SL2 Auto Trans Shifting Problems

There is a switch that can be set to either "economy" or "performance". Sounds like yours possibly got changed to the performance setting which winds out the RPMs to develop higher power before shifts.

Bob

There's no switch but, I was told by the dealer that the car "learns" how I drive and makes adjustments accordingly. When I mentioned that I have not changed the way I drive so the car should "remember" what it "learned" did not sit well with the mechanic. He told me that "these cars perform best when driven hard" and that this problem would disappear with rougher treatment. That was about 8 months ago. This problem has gotten progressively worse.

Jake

Ratbert wrote:

I just found out that there is a vehicle speed sensor. If it is an electronically controlled transmission, could the vehicle speed sensor could fail over time and not allow proper shifting? Is that what controls shifting? Or, is it merely for the cruise control?

jake292 wrote:

To help in troubleshooting you need to be more clear with the symptoms. Is the delayed shift occurring only between one set of gears or is it on all three up shifts (1-2, 2-3, 3-4)?

Bob

I'd start with changing the fluid and filter. See if it improves. These valve bodies get clogged if the fluid is not changed at regular intervals. It may also be a solenoid starting to go flaky and open up so not engaging when expected. It also could be the speed sensor as you suspect as well. You may need to wait till it dies completely before you can diagnose this at that level. Are you getting any trouble light and trans codes?

I was thinking the same thing. Changing the fluid and filter is the cheapest and easiest option and a good starting point. Bob, I could actually hear the "plunk" that the pockets of thicker fluid made as they dropped into the catch pan. One interesting thing; the trans filter off, it was still pretty hot so, I tossed it to the ground after removing it from the last few threads by hand. When I was finished and cleaning up I noticed something on the filter, right over the threaded hole that fixes it to the engine. It was a large and powerful magnet which, still had some metal shavings caught before entering the filter. I have never seen such a thing. I wish I would have noticed it before I finished, it did't seem worth draining all my fresh transmission fluid back out (not to mention, catch pan already full). I might get some use out of the fluid in it for a while and change it out again sooner than the suggested interval, making sure to replace the magnet. The good news is that like my Dad would have said, "it runs like a scald assed ape." Which as I understand it, it good.

Bob Shuman wrote:

The Saturn spin on transmission filter (looks like a regular oil filter) has a magnet integrated into the design. As such, it that gets replaced when the filter gets replaced. This type of filter was a novel idea and in my opinion is head and shoulders above the filter and magnet in the bottom of the in the pan design used in nearly every other transmission I've ever seen.

I also like the fact hat the trans has a drain plug as this makes it a lot easier to do this job. The reality here is that given the location of the drain and filter, it is far easier to change the transmission fluid and filter than the regular oil!

Hope that your transmission continues to run good. I'd plan on changing that fluid about every 30K miles.

Bob

Thank you very much for your help, Bob.

Bob Shuman wrote: