Overdrive troubles

Post by **Walt** » Tue Feb 14, 2006 10:51 pm

Not really sure how to describe this problem, but when in overdriver, my truck periodically shakes. By shake I mean that it feels like the tranny downshifts for just a fraction of a second. Not enough to cause a jerk, but very noticeable nonetheless. It only happens when my truck is in overdrive, moving at a steady speed, with steady throttle. Normally my drive to and from work involves alot of hills, so I'm rarely keeping the same speed. But a month or so ago, I was driving on a flat section of road in Jackson, MS, doing about 50MPH steady, and it started doing it. Maybe once every few minutes, but with no regularity. Then tonight (a few hours ago), it did it again over a period of an hour. My speeds ranged from 40MPH to 75MPH over a 60 mile stretch with no hills, and it acted up the whole time.

It only happens when the truck is in overdrive. I can put the gearshift in "3", and it NEVER happens, and I can constantly accelerate or brake, and it never happens. I wonder if something's up with the transmission.

Any ideas?

04crewvt · Post by **04crewvt** » Wed Feb 15, 2006 3:56 am

Get thee to a transmission shop pronto. The 4l60E transmission, which is the electronic version of the th700r4 transmission, looses overdrive gear fairy easily your hill driving has probably been all in overdrive which is not good for these transmissions. The overdrive pawl in the transmission gets worn and then can break off causing you to loose all gears. I have had this happen in my old GMC Jimmy to the tune of a $900.00 rebuild.

Post by **Walt** » Wed Feb 15, 2006 7:13 am

Hmm....well I'm glad for my extended warranty. Most of the hills I'm refering to usually aren't bad enough tomake me downshift into 3rd, so that sounds like a good explanation. Thanks!

EDIT: Oh yea, and my wheels are hard to turn when I'm stopped. I've checked the PS pump fluid, and everything is good there. Think the pump is going bad? It does it about 75% of the time I'm stopped and try to turn the wheel either way. But it works fine moving.

Another EDIT: Just talked to someone at my local dealership, and he said it might be something to do with the plugs/wires/distributor, causing a slight miss-fire under certain conditions. I don't know, but it should be convered under warranty, so I'll take it in and see come Monday. Hmm...this might give me an excuse to go ahead and change my plugs

Snoman002 · Post by **Snoman002** » Wed Feb 15, 2006 7:54 am

If you get a chance very very lightly touch the brake pedel (just enough to get the lights to some one, not enough to engage the brakes) when this happens. If it goes away it could have a TC lockup problem. The 4L60E did have a problem with the TC lockup but that was supposed to be fixed on trannys with a build date later than Nov '99. It's just a possability and easy to test for.

Post by **Walt** » Wed Feb 15, 2006 10:45 am

There isn't enough time to press the brake pedal. It happens in a fraction of a second and goes back to normal.

killian96ss · Post by **killian96ss** » Wed Feb 15, 2006 11:43 am

4th gear lock up solenoid going bad? Torque converter clutchs or dampening springs going bad? Any codes or lights? It also sounds like you need a new PS pump.

Steve

AZS10Crew · Post by **AZS10Crew** » Wed Feb 15, 2006 3:49 pm

Just a shot in the dark here, but have you removed your MAF screen? My 6-cylinder Camaro did the same sort of thing after I removed the screen. Once I put it back in, no more stuttering. Just a thought.

shakin · Post by **shakin** » Wed Feb 22, 2006 3:05 pm

My truck was doing the EXACT same thing for about the last three months until yesterday. I was a quart low on tranny fluid. I have no idea why, there is no leak at all. Added a quart, and it runs like new. If it happens again, I will be headed to the dealer ASAP. Anyone have any idea where that quart of fluid could have gone? I know tranny's cant "burn" the fluid, and like I said, it doesnt leak. I just figured the factory messed up.

Post by **Walt** » Thu Feb 23, 2006 8:35 am

Hmmm....guess I need to check the tranny fluid before taking it in. Never done it before.... anything special I need to know about?

killian96ss · Post by **killian96ss** » Thu Feb 23, 2006 9:00 am

wamason wrote:Hmmm....guess I need to check the tranny fluid before taking it in. Never done it before.... anything special I need to know about?

#1, make sure the truck is fully warmed up by driving it a few miles. #2, park on a level surface. #3, start engine and put it in neutral or Park. #4, check fluid level. If you need to add fluid only add about 1/2 quart at a time to get to the correct level so that you don't overfill the transmission.

Steve

SONOMA915 · Post by **SONOMA915** » Thu Feb 23, 2006 3:29 pm

I would check the trans fluid, I had a the RPM hunt a couple times in overdrive. The trans fluid was low. My power steering did the same thing your talking about, I noticed I could give it a little gas and it would turn fine. It was the power steering pump. Replaced under warranty. Hope this helps.