Random Downshift of Auto Tranny

[soonercruiser]

I've had 3 episodes of downshifting of the tranny on the 2005 Turbo Lite in the last week or so.
When in Dover for the show, I pulled onto the highway, and she would not go beyond second gear...running a few minutes at 4,000 rpm before it shifted normally.
I did even pull off, wait a while, and restart to clear this. No change at that time. Eventually cleared up.

Then on the Interstate on my way back, while on cruise control, it would downshift into second when going downhill, at around 70 mph. That cleared up when I eventually turned off the cruise control. But, I did use the cruise control normally down the road.

Then again today....engine cold....I pulled out of the garage and headed towards a show, it would not go beyond second gear for about 2 minutes. Thereafter, if was fine. This was NOT YET USING CRUISE CONTROL!

What is the likely culprit, since it is not "cruise" associated all the time???

(Got tranny service scheduled next week....the 50K standard service.)

[LionPT]

Sounds like it's slipping to me...warn bands probably.

[ptcruisersteve]

Sounds like you are going into limp mode when there is a problem with the transmission.

The second gear limp-in feature allows the vehicle to be driven to a dealer for servicing without damaging the transaxle. In the event that the problem has been momentarily the transaxle can be reset to regain all forward gears. Stop the vehicle and shift to park (P). Turn the key off then restart the engine. Shift into D and resume driving. If the transaxle can not be reset, dealer service is required to resolve the issue before it can be reset.

Are you getting P0700 code?

[soonercruiser]

No codes.
And the stopping > Park> shut off > restart > Drive > doesn't reslove the issue when it happens.

I really do not want to heard the "tranny slipping" at 48K!

I was hoping it was some kind of sensor problem.

[soonercruiser]

No other contributions to the problem?

[ptcruisersteve]

How are you checking for engine trouble codes?

[KA9VQF]

Have you checked the transmission fluid level?

[Busted_PT]

If slipping you would feel the sensation of revving but no acceleration. Kinda like not in gerar. Your describing a sticking shift solenoid or something like that. When it doesn't shift you would feel rpms up but hang and when you let off the gas it pulls the car down in speed.

[ptcruisersteve]

I would suggest that as long as you are getting a service fluid/filter change you might want to pick up a new SOLENOID MODULE, SOLENOID PACKAGE and have them install it. As Busted_PT posted I think they will find the solenoids sticking.

I noticed that my OBDII Scan Tool does not recognize the transmission code errors. It just lets you know that there are codes stored that are not recognized and that it does not always trigger the P0700 general transmission error. You can take it to a transmission shop and have them scan for the TCM codes. They usually will do it for free.

After reading your first post again I realized that you are not in limp mode. In all cases of any automatic transmissions if the disc's are worn then the RPM will creep up and the MPH decrease , or the MPH will reduce and the RPM maintain, this is a worn transmission not simply down shifting. this is a worn transmission not simply down shifting.

[NitroPT]

Good info here!