Cadillac CTS First Generation Forum - 2003 - 2007 Discussion, 2003 CTS - Transmission Problem in Cadillac CTS Coupe, Sport Sedan and Sport Wagon Forums; I'm having a problem with my transmission, the car shifts fine up to 5th gear, and after about a mile ...
I'm having a problem with my transmission, the car shifts fine up to 5th gear, and after about a mile or so driving on 5th it kicks back to 4th gear and stay there until I turn the vehicle off and turn it on again, and looks like the transmission goes into a fail safe mode, the rpm and shifting from 1st to 4th are all different, I cant remember what the check engine light code was, but it relates to the 5ht gear solenoid. The first time this problem happened was about 2 and half years ago, and I took the car to a transmission place, and the guy told me the solenoid was fine, but had to rebuild my entire transmission for $4 thousand dollars, I said no thanks... So I told him just to change the fluid, so after that fluid change the problem was gone.. until now..
Just an observation, the problem started again few weeks ago at the end of winter here in Georgia, and one thing I notice, whenever the outside temperature was below 40 degrees the transmission would operate fine, no problem, and if temperature was above 40 or so, the problem starts..
So, I purchased some Amsoil synthetic transmission fluid and took to a shop to have the fluid changed again,(did other work as well, water pump, timing belt and valve cover gasket) the problem still happening, but now whenever the outside temperature is above 65 degrees, below 65 car runs normal..
What could be the problem, do I have to do another fluid change, because I know when you do a fluid change you only replace part of the fluid in the transmission.. maybe I have too much old too old fluid in the transmission?
One common solution to the transmission woes associated with our cars is an external transmission cooler. The CTS already has a remote cooler built in to the radiator, but it is garbage and the fittings corrode and break more often than not. The solution is to disconnect the factory cooler and run those hoses into an aftermarket/external cooler, such as the B&M SuperCooler.
If I were you, I would have one such aftermarket transmission cooler installed and have your transmission flushed of all the old fluid and filled with AmsOil or Royal Purple ATF. If the problem persist, it is time to address that solenoid. Best of luck, hope this helped.
I have the same problem but instead of goin into 4th gear I'm going into 3rd.... My code says seleniod c stuck on....I'm also running 230k tho...I'm changing the tranny... I ordered one with 60k on it.... It's not worth messing around with fluids and stuff