: Transmission issue



Snowman269
07-08-09, 05:45 AM
Sorry if this is posted in the wrong spot, I couldn't find a drivetrain specific area.

My 99 Deville with 100,000miles, acts like the fluid needs to get pumped through the trans before moving.

After it's been sitting over night, the first time for the day, I start it up, put it in gear, drive or reverse, and it barely moves, then put it in neutral, wait, then it'll go.

But if I start it, and just wait 30 seconds while it idles, the car moves normally.

I changed the fluid, fluid was good. The fluid has air bubbles in it on the dipstick. Other than that, the car shifts fine.

I'd like to fix this before it costs big buck to fix, unless these transmissions are easy to find used?

Submariner409
07-08-09, 08:38 AM
Either the torque convertor or the transmission oil pump system may still have air trapped - but not likely. If so, it will eventually bleed itself.

How full is the transmission now ? The 4T80E is a dry sump transmission and there will be NO fluid on the dipstick with the engine off. You must check the fluid level with the engine running warm in P, and adjust the fluid to halfway up the dipstick hashmark.

Once all that is checked, take the car to a quiet stretch of road and do a series of manual 1-2-3-2-1 upshifts and downshifts from 0-70 and back down. The transmission should shift firmly and quickly up through the 3 gear selections - try to shift at about 5500 rpm, and on the downshifts the transmission will NOT shift until the resulting rpm is within the safe operating band: the transmission WILL NOT let you break anything. You can put the stick in 1 at 80 mph, take your foot off the gas, and the car will decelerate itself safely.

If all that doesn't clear things up, you have either failing 1-2 or 2-3 shift solenoids or a sticky valve body, any of which can be repaired with the front end up on jackstands. Learn to pull your DTC's and see if there's a transmission code set. It's all built into the car: sticky thread at the top of the forum "How to pull codes". You want the link with "obd2" in the URL.

Snowman269
07-08-09, 08:45 AM
Once it's warm, engine running, fluid is slightly below the full mark, with tiny air bubbles.

After 3,000 miles, there shouldn't be any air left in the system, right?

Submariner409
07-08-09, 09:00 AM
Not after 3,000. Your post sounded as if you had just done the change. Pull your DTC's and find out if there are any transmission codes set. Sounds like a pump or line pressure problem.