Tranny issue, need some help figuring it out

[992dr]

Got in touch with FTI, great people to deal with. He was very helpful.
I'm going to get it flashed back to the stock tune and see where we go from there. If it still has the same symptoms, FTI will go through it for me at no cost. That's some pretty awesome service.

 

[KMeloney]

Please keep us posted. I'm watching this thread.

 

[992dr]

Will do
I'm planning on swinging by the dealer for them to flash it back to stock sometime this week.

 

[992dr]

Just got back from the dealer.
I did not have a tune for them to re-flash.
POS f**kers lied.

 

[mattluttrell]

Is this a bad ujoint causing a vibration? I've had out of balance driveshafts or bad ujoints cause this.

 

[992dr]

It only happens when the converter locks up at 35mph and stops at roughly 45mph.

I'd think if it were a u-joint it would be more consistent.
I'll check them out though, just to be sure.
Thanks

 

[992dr]

matt,
went under and checked the u-joints. They felt tight. One thing I noticed was a little slop in the yoke.

Here's a couple of quick clips





Well, I had spoken with the owner of the converter company. Cool guy, very helpful.

From the explanation I had given him. He said that it is going to be one of two things, either the converter or a misfire. I just changed my plugs and wires.
It has a slight hiccup at idle and the tuner at RPM picked up several misfires while we were doing a road tune. Its pretty much been like that since I bought it. And since it doesn't throw any codes, not one tech has even attempted to try to resolve this. All I hear is, if it doesn't throw a code, we cant see anything.

Now, how the hell do I figure out exactly where this misfire is coming from?

This was something I had brought up with the original shop, his answer was "its old".
Misdiagnosis and a ton of money down the drain.

 

[mattluttrell]

I don't have any answers.
I will say that my Esky will have a slight misfire at a stoplight once every couple weeks. It won't happen at speed. I also have new plugs and cables. It is never bad enough to be stored in the computer.

The u-joint problem I speculated happened to me when one had needle bearings completely corroded. It caused driveline vibrations at 50mph+ when you were coasting or slowing. They weren't there on acceleration because the torque was keeping it close. It loosened on coast. My u-joint issue was obvious.

A little slop in your yoke is healthy. Lack of slop is actually a problem.

I don't have any Tahoe related advice or guesses. Good luck.

 

[moineau]

By DIY I meant the screen on the dash. I think it's called that. I have a 6.2 so I don't have Afm. Maybe somebody can chime in and tell if it shows on the cluster when it's in 4 mode or even if it's available on a Ppv

I believe you mean DIC (Driver Information Center), not DIY. At least in the Yukon XL Owner's Manual, DIC is used to refer to the cluster panel providing idiot lights for anything wrong (including a small text readout).

DIY is sometimes referring to Do-It-Yourself, so I may be incorrect for GMC trucks but I think the post should have read DIC (yeah, U pronounce it like U want...)

 

[992dr]

Does anyone know what the operating pressure should be on a 4l60e trans?



EDIT Found my answer, I think. Does 190psi sound right? If so, I'm at 80psi. Less than half. Supposedly, this is what's giving me the shudder under lite throttle.