Tranny "Heads UP" and recommendation request

[07 Denali]

Hey Guys, I'm new to the site. I wanted to give you guys a heads up. Others may have posted about this already, and I haven't done a search, so pardon me if this has already been stated. I took my wife's 07 Denali in (finally) to disconnect the heated windshield washer reservoir and get the passenger side rear defrost cable soldered back to its plate. I also let the service tech know that when we back out of the driveway and shift the vehicle from reverse to drive that the transmission was taking 4-5 seconds to engage. There were also instances where the transmission seemed to hang in a gear a little longer before shifting to the next under normal driving. Tech thought it might be a shift solenoid. Turns out GM put out a bulletin for the symptoms I described. Solution: replace some internal seals in the transmission. So as I type the transmission is being removed from the truck and disassembled. Thought I would pass this along since many of the '07s are getting close to being out of warranty and the symptoms are barely noticeable and intermittent.

Also, anyone know the capacity of the front and rear differentials and transfer case and have a good recommendation for the fluid to use in the transfer case? Looking to do some general maintenance when I get it back from service.

 

[Modded]

Thanks Brian. I wonder if its specific to the Denali/Escalade 4L80E tranny because most of the Tahoes and regular Yukons have the 4L60E?

 

[07 Denali]

I'll ask the question when I go pick it up. If it is not ready today, I won't be back in town until the 9th, so I apologize in advance for the potential radio silence.

 

[bauer4567]

I do believe it is the Denali / Escalade tranny. this work had already been done on my Denali when I got it...

 

[felixgun]

I've heard of this with the 6 speed/6.2L... I have a 4.3 and don't have this issue. Ghoster I think had posted a similar issue with the late shifting and when he got his AutoCal/BB Tune for his ECM/TCM it fixed the shifting issue... without physically changing anything. Maybe he will chime in...

 

[phileaglesfan]

I know a friend had that trouble with his 2008 A6 Corvette. His dealer fixed it but then he lost all power at a busy intersection so they had to take it apart again.

 

[B.G.]

Hmmm, for some reason I feel as if I am sensing these problems with my Hybrid tahoe. Its funny because it only happens when its really HOT outside or really Cold!...Does weather play a role in these symptoms...

 

[ajs800]

I had similar issues with our 07 LTZ at 36k mile mark and after separate trips to the dealer and then a 2nd dealer, they discovered that a couple of the pressure sensors were faulty and was causing low pressure which in-turn was causing some gears to hang, over rev, slip, etc. at times.... it only acted up during extreme temps. It's been fine since (2yrs).

 

[edgaranah1]

This is the first time I have heard of this issue. I have an 07 with the 5.3 and getting close to 70K and had no problem with it had it since new. Probably It is just the Denalis

 

[07 Denali]

I was able to look at the Tech's notes briefly before having to give them back to the cashier at her request. What I gathered from them along with information provided by the service rep is that seals need to be seated a certain way (there are markers on the seals and markers on the housing that need to line up). I don't know if both the transmission mated to the 6.2L and the transmission mated to the non 6.2L engines are involved, but I read in the bulliten that this is related to transmissions assembled prior to December 2008 (I assume in the new body style only). If I come across any additional information, I will post it.