Help! Wife wants to trade Yukon for Sequoia if..

[BADDGMC]

Hi everyone.

2008 Yukon with 120k.

Oil change done every 4-5k miles. Transmission oil was replaced a year ago by GMC dealership, I constantly check it to make sure it's full and clean.

Here's my problem.

Every now and then I get a hard shift from 1st to 2nd, it's not a slip, it's more like a "kick or jolt". It also does it when going from 2nd to 3rd but not as hard as 1-2.

The craziest thing is that as soon as it starts doing it, I can pull over, shut the engine off for literally 30secs, turn it back on, and then it drives perfectly.

Transmission Temp. is always within the norm. The engine is not making any weird noises and I am not getting any check engine codes. Also, no signs of leakage.

I have taken it to the GMC dealership but they can't find anything wrong. They have even done a test drive but to my luck it doesn't do it in their presence (ofcourse). They said it's hard to pin point exactly what it is because there's no check engine codes.

I'm almost sure it has to be something electrical (sensor) rather than mechanical right? If not, it wouldn't do it sporadically and reset itself after the engine has been turned off for less than a minute.

Has this happened to anyone? If not, I'll take any advice I can get.

Thanks in advance!

 

[drakon543]

id go to a legitimate transmission shop and have a diagnostics done. your well outside the warranty and stealerships are almost useless unless its a gm known issue. a specific transmission shop should be able to diagnose or give you a real good idea what probably wrong and cost. most of the times a transmission shop diagnostic fee is reasonable so i would suggest a good shop. aamco or something.

 

[thompsoj22]

Under the right circumstances mine with 130k will do the same thing. nomally it is under light throttle and accellerating down hill? it never does it when accellerating normally as in a freeway on ramp.

 

[BADDGMC]

id go to a legitimate transmission shop and have a diagnostics done. your well outside the warranty and stealerships are almost useless unless its a gm known issue. a specific transmission shop should be able to diagnose or give you a real good idea what probably wrong and cost. most of the times a transmission shop diagnostic fee is reasonable so i would suggest a good shop. aamco or something.

You're absolutely right on that one. That's my next move once I get all the feedback I can from here. My transmission does have another 2yrs of warranty left so I'm sure the dealership would try to bs me.

 

[BADDGMC]

Under the right circumstances mine with 130k will do the same thing. nomally it is under light throttle and accellerating down hill? it never does it when accellerating normally as in a freeway on ramp.

Yes on the light throttle part, but it doesn't usually matter if it's on an incline or not.

I just bought an AFM Disabler on Ebay. Maybe it has nothing to do with it, but I wanted to try one out anyways. Heck, at this point I wouldn't be surprised if something like that fixes it.

 

[thompsoj22]

Yes on the light throttle part, but it doesn't usually matter if it's on an incline or not.

I just bought an AFM Disabler on Ebay. Maybe it has nothing to do with it, but I wanted to try one out anyways. Heck, at this point I wouldn't be surprised if something like that fixes it.

I honestly feel it is just a characteristic of the 6 spd. I hear alot of members saying the Black Bear tune is the ticket to a happy trans but i havent considered it yet.

 

[Clinton Ellyson]

My 05 does it too, but only going from first to second. My 02 Suburban does it as well, but not as bad. I'm thinking more along the lines of the universals since I'm sure none of mine have ever been replaced. Then again I'm no transmission guy by any stretch of the imagination.

 

[BADDGMC]

I honestly feel it is just a characteristic of the 6 spd. I hear alot of members saying the Black Bear tune is the ticket to a happy trans but i havent considered it yet.

Interesting.

I should be getting the disabler by Sat. or Monday the latest. I'll let you know how it goes.

 

[BADDGMC]

My 05 does it too, but only going from first to second. My 02 Suburban does it as well, but not as bad. I'm thinking more along the lines of the universals since I'm sure none of mine have ever been replaced. Then again I'm no transmission guy by any stretch of the imagination.

Is it constant though? Or sporadic? That's what pisses me off, my truck can do a week of perfect shifting, then out of the blue start with the hard kicks and jolts.

Again, as soon as it starts doing it, I pull over to the side of the road, shut the engine off for 30secs, and wallaah.. back to normal.

 

[Clinton Ellyson]

Is it constant though? Or sporadic? That's what pisses me off, my truck can do a week of perfect shifting, then out of the blue start with the hard kicks and jolts.

Again, as soon as it starts doing it, I pull over to the side of the road, shut the engine off for 30secs, and wallaah.. back to normal.

Nope, mine is constant. Wonder if it may be a speed sensor. When it does it next time see if the cruise control still works. I had to clean the connection on mine a few years ago, but I don't recall if I was having any shifting issues at the time.