Ha gang, I have a 99 with auto. the od keep going in and out. any suggestions.

 

How many miles on the trans? Any mods? Check trans fluid to start with then go from there.Does it happen on the highway or around town?........................Paul

 

4th gear has a "lock up" function, at a certain speed it will go into lock up, this is barley felt by the driver but can be felt if your looking for it. Mine is custom set at 47 mph, I don't know the factory default setting. Travel on smooth highway accelerate lightly and feel it shift to 4th and then feel for the lock up after that and note speed. Once you drop below that speed it will go back to regular non-lock up 4th, increase to lock up speed and you should feel it lock up again. All light acceleration. If this is happening, you have lock up, some people call it OD. Hope this helps you figure out whats happening (or not happening). If your profile were filled out, I might be able to make further recommendations based on your location.

 

it has 56000. I notice it starts around 45mph.

 

Been there, done that...feel your pain.

Mine started at around 45mph also...then it would slip in and out of 4th gear lock up everytime I encountered the slightest incline on the highway. It was driving me crazy, so I took it to a reputable tuner, and they tried everything possible with HP Tuners, to try and correct what we thought was a lock up problem...to no avail.

When all was said and done, I had to rebuild my tranny, due to 4th gear band being burned. What's funny, is the tranny worked perfectly in all other gears, and there was no slippage in the usual 2-3 shift. That's where I've had all my other tranny issues. This one caught me by surprise.

F.W.I.--My problem developed after a highend race with a Ferrari on the open road, where I was forced to shift into OD @ 6750 rpm, at around 135mph because I had run out of cam and 3rd gear rpm.
Well, I'll never do that again! Immediately the DIC started displaying *HIGH TRANS TEMP*...I slowed to 55mph...went straight to a transmission shop...had the tranny flushed...too late...burned up 4th gear band and something else...I can't remember the other thing. Beat the Ferrari, but at what cost? Not worth it.

I still race...just don't go into 4th/OD anymore at WOT...need to let off for a moment when shiftinmg into 4th, because it's an overdriven gear. HTH!

 

ummm, drive in 3rd gear all the time? bub

 

Had the same thing happen to my Trans-Am. Tranny had to rebuilt, so it got all the goodies.

 

see if cruise control works tcc brake light switch may have slipped and needs adjustment

 

Thanks guys for the reply I'll check all suggestions.