I have a 07 monte carlo lt 3.5 with the flex fuel. It is about to reach 80,000 miles and the issue I have at the moment being when I'm at a stop light as I accelerate it gets up to about 2-2,300 rpm before it jumps forward and finds a gear it seems. It only happens once in a blue moon and my warranty is up. Has any one had any issues similar to this or figured out what it could be dealing with? Any help will be greatly appreciated.

 

Not certain if the 07 trannies are the same as mine, but when mine was having those issues it was the shift solenoid acting up, they are controlled by line pressure and the hard shifting is the pressure building up higher than normal and essentially causing it to slam into the next gear. They can be replaced. I would first check to make sure you don't need to change the tranny fluid, but I would just recommend a fluid and filter change, in my case being an 02 they don't recommend doing a flush as it can actually make the tranny worse by loosening up the crud built up inside the tranny, but a fluid change and filter change may do the trick for you. Again I am not certain if they have the same trannies so I hope another member chimes in if they know the cause and I am wrong, but I do know the trannies in the 00 - 05 for certain have that issue, but I honestly don't know if they switched up the trannies or improved the design for the 06 and 07 monte's. There are links on youtube on how to do the switch of solenoids yourself and if you are handy enough you can do it in your driveway.


ZZP Platforms


sells replacement solenoids and you can buy rebuild kits off of ebay as if you buy them from a shop they will cost a lot more.

 

Found this on another website, there was a service recall for your transmission as apparently there are problems with the torque converter. Maybe check with your dealer to see if this was done?

There is a technical bulletin on your car. This may be the problem.
Models:
2006-2007 Buick Rendezvous, Terraza
2006-2008 Buick LaCrosse,
Lucerne, Allure (Canada Only)
2008 Buick LaCrosse Super, Lucerne Super,
Allure Super (Canada Only)
2006-2007 Cadillac DTS
2006-2007 Chevrolet
Avalanche 2500 Series, Malibu, Malibu SS, Malibu Maxx SS, Monte Carlo, Monte
Carlo SS, Silverado Classic, Suburban
2006-2008 Chevrolet Express, Impala,
Impala SS, Uplander
2006-2007 GMC Sierra Classic, Yukon XL 2500
Series
2006-2008 GMC Savana
2006-2008 Pontiac Grand Prix, Grand Prix GTP,
Grand Prix GXP, G6, Montana SV6
2006-2007 Saturn Relay
with HYDRA‐MATIC(R) 4T80‐E (MH1), 4T65‐E
(M15), 4L80E (RPO MT1) or 4L85E (RPO MN8) Automatic Transmission
Supercede:
This bulletin is being revised to add additional models. Please discard
Corporate Bulletin Number 08-07-30-016 (Section 07 -
Transmission/Transaxle).
Notice: It is critical that all internal
transmission components are thoroughly cleaned and the transmission cooler be
flushed using the J 45096 transmission oil cooling system flush and flow test
tool. It is also critical that the system be flushed in both directions to
capture any friction material trapped in the cooler. Be sure to back-flush first
to push material out of the cooler, following the instructions provided with the
J 45096.
The purpose of the bulletin is to provide technicians with additional
diagnostic information on transmission slips, will not shift, or may overheat
conditions. DTCs P0894 or P0218 may be set on the above transmissions.
These conditions may be caused by friction material debonding from the Torque
Converter Clutch (TCC).
If any of these conditions are observed, the friction material from the TCC
may have circulated throughout the transmission, the cooler lines, and the
transmission cooler. Remove the transmission oil pan and inspect for friction
material in the filter.
If friction material is observed in the trans pan or filter, the torque
converter is the possible cause and it will be necessary to disassemble the
transmission completely for a cost comparison (include a torque converter and
filter in the estimate). Refer to service bulletin 08-07-30-001 for cleaning and
inspection instructions of the valve body assembly.
After the cost comparison, either repair or replace the transmission in the
most cost effective way. If it is necessary to replace the transmission, contact
the Product Quality Center (PQC) per the most recent version of bulletin
02-07-30-029.
.
Basically the inside of the torque converter may be coming apart and spreading friction material through the transmission.


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