Tranny issue, need some help figuring it out

[992dr]

Its for an 07 Tahoe PPV
Here's my problem.
When accelerating it drives fine and shifts fine.
It's when I'm at cruising speeds, doesn't matter how fast or slow. If I stay at any speed for even the shortest period of time, it starts to shudder/shake. I feel it in the pedal and the steering wheel.

What are your thoughts on this?

Any info would be appreciated
Thanks

 

[08grey]

I had this issue years ago in a different vehicle at 1500 rpm it would shake. Turned out I had the wrong type of tranny fluid. Changed it out and all was well. Damn jiffy lubes

 

[992dr]

I need to make a date for the tranny to get flushed.
Though I did check it out and its still red.

 

[992dr]

Well, made an appointment for a diagnostics check, nothing came up using HPTuners.
Though I did not know it should have been hooked up while driving and he did not mention it either. It was shuddering at roughly 43mph and up. I took it out with the mechanic to point out the problem, he noticed it later in the drive. One thing he did notice was the converter was not locking up at highway speeds. He hit the brakes while driving and nothing happened, the rpms stayed where they were. I bought a new converter a bigger cooler and a shift kit hoping this would eliminate the issue. Boy was I wrong. Not only is the shudder more pronounced at highway speeds (or in 4th gear) it shudders down low now to around 20/35mph. I'm all for preventative maintenance but I think I just wasted a lot of money, when I should have just bought a new tranny.

Now I have a question. People have mentioned something about V4 and V8 mode and seeing it on the dash. This seems to be one of the culprits to the shuddering/vibration. What is this and where is it located?
Is this an option in the PPV Tahoes?

Thanks

 

[08grey]

The mode you refer to is Afm. It kicks the down to 4 cylinders when you are cruising at highway speed to help mpg. It's supposed to show on the DIY when it kicks in. Not sure if the Ppv have this.

I have a question. When you are cruising if you go to speed up does it shudder the ought the acceleration as well or go away?

You mentioned 4th gear. Can you lock her in a lower gear and get to the same speed and see if it still happens? This will tell if it's really 4th related.


Sounds like you brought good stuff. Don't fret you could have brought a new tranny and found out its a motor mount.

 

[992dr]

Sorry, new to the NNBS scene. What is a DIY? Or, what does it stand for?

Under acceleration it doesn't happen, only when cruising at the same speed. If I'm on the highway or side roads I cant cruise without it happening, as soon as I speed up it goes away.

I will try that tomorrow. I'll hold it in third and see what happens. It just started doing it at lower speeds after getting the work done.

G-d, I hope its not something like a motor mount. It doesn't feel like it but, you never know. I'm going to check all of the mounts tomorrow morning.

Thanks for the reply, I appreciate it.

 

[08grey]

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

 

[992dr]

I'm not 100% sure but, as far as I know, its available.
I don't have a screen, just a cluster, hah. I have never noticed anything about afm on the dash.

 

[STORMIN08]

When you scroll through the vehicles info scree....
It appears on the instant MPG read out....
V4. Or. V8 .

 

[YukonButICanToo]

I know exactly what you're talking about...it's caused by a transmission lock solenoid (or something like that?), check with the dealer for the replacement http://gmpartsonline.net

I had to replace mine on my Silverado and it went back to normal...my gas mileage also got much better, oddly enough.

 

[992dr]

When you scroll through the vehicles info scree....
It appears on the instant MAG read out....
V4. Or. V8 .

I do not have a screen. There are only two things I can scroll through, my trip-o-meter and odometer.

I know exactly what you're talking about...it's caused by a transmission lock solenoid (or something like that?), check with the dealer for the replacement http://gmpartsonline.net

I had to replace mine on my Silverado and it went back to normal...my gas mileage also got much better, oddly enough.

Really?
That would really suck if that was it. I just dumped enough $$$$ into it to buy a new tranny.

I think I'm going to call a tranny specific shop after the holidays. Not a good way to end the year especially around the holidays.

 

[992dr]

I broke down and brought it to the dealer for a diag scan. I was fortunate enough to take it out with a tech, he felt and heard everything through every gear. I told him everything that I had done and he is going to let me know tomorrow what the results are. Hopefully its nothing major.

 

[992dr]

Problem solved

 

[livingez_123]

Problem solved

Do tell.

 

[electro]

Solved how?????

 

[livingez_123]

must be some secret squirrel stuff.

 

[992dr]

Sorry guys, I didn't realize this thread had any activity.

Long story short, the problem was not resolved.

I'm not pleased with how it drives with the FTI converter, it's a complete dog. Never mind the other problem.
It doesn't drive anything like my 2dr 2wd with yank 3200. Not sure if its the extra 800 to 1k pounds of the NNBS or what.
I'm taking it to the dealer for them to re-flash the tune back to factory. I'm not sure what the guys did with the tune but I'm not to thrilled with how it drives.
I'm more than likely going to put an OE quality converter in unless FTI gives me another idea about the converter. Maybe go with a different stall.
I don't know, I'm aggravated about this whole situation.

 

[992dr]

I have a random question. I took out a couple of friends and pointed out the noise at 35/45 mph. The passenger in the back said "it feels/sounds like its your rear end, I felt it in my butt"

Is it possible that the rear end could be the problem?
Is it possible for the rear end to hit that sweet spot at the right speed and start to vibrate?

Thanks

 

[08grey]

Check your drive shaft might have a bend maybe u joints as well. I have a buddy they used a forklift to motive his truck at auction. Put a huge dent in the drive shaft. Luckily it doesn't do any thing to the drive quality but everyone who see 'a it says damn what the hell happened there.

 

[992dr]

I looked at my driveshaft, looks fine. I did notice one of my lower links is bent.
I don't see a bent link causing any issues like I'm having. I'm going to order one this weekend.

This sh*t pisses me off, one simple problem turns into many issues after one shop had there hands on it.