[Guest]

We recently bought a 2007 Commander with a 4.7 flex. We love the vehilcle but it has an issue that I'm afraid is going to be hard to fix. It hunts between 5th direct and 5th lockup, but only once in awhile not all the time. Any ideas? Thanks

 

[browens1534]

I know there is a TSB out for an ECM reflash that deals with a feeling of "being held back". Maybe the trans just needs a relearn on it, you have to go to the dealer for that too... Best bet would be to get the transmission services at a Chrysler-Jeep dealer (fluid filter and relearn). The 545RFE is a great transmission. It could also be another number of things, has the engine ever had a tune up? Ran fuel cleaner through it? The throttle body cleaned of carbon?

 

[blackstratus]

My parents have a 2001 Dakota 4.7 with the 4 speed transmission that I think is related to your 5 speed transmission in your Commander. Even if it isn't, they had the same issue for about 2 years with this truck doing the same thing as yours. It would lock and unlock the torque converter. No check engine lights or anything like that. They took it to the dealer and they found out the solenoid pack was faulty. They replaced it and it has been at least 10,000 miles and it no longer does the unlock and lock thing. This was very intermittent also just like yours. Might be something to look into.

 

[ImperialCrown]

Both 4.7L trucks use the 545RFE (45RFE) transmission. As stated, look for TCM fault codes with a capable scan tool, not all codes will light the dash 'ck eng' light and not all OBD II engine code readers will read transmission codes. The latest and greatest PCM/TCM software revision followed by a quicklearn is always recommended.
P0740 may set with a hydraulic, mechanical or electrical torque converter clutch problem, but a scan tool may also tell you the reason 'why' it is disabling lock-up. False temperature and speed sensor signal information are 2 reasons for hunting or intermittent operation in an otherwise functional TCC (torque converter clutch) system. Since the speed and temperature inputs are deemed as real by the control module, it may not set a fault code for an 'unlocking' TCC.
The control module looks for an appropriate RPM speed drop when the TCC is activated. If it doesn't see the speed drop or it doesn't drop enough, the fault code is set.
It doesn't always have to boil down to a transmission rebuild, but front pumps and torque converters may be replaced as a pair if wear has occurred. Wear here could cause a hydraulic TCC turn-on leakage.

 

[oknahs]

We recently bought a 2007 Commander with a 4.7 flex. We love the vehilcle but it has an issue that I'm afraid is going to be hard to fix. It hunts between 5th direct and 5th lockup, but only once in awhile not all the time. Any ideas? Thanks

I own a 2006 and the transmission filler is sealed and must be drained and filled by a Chrysler garage. You 2007 probably never had a change and this could be causing the problem. Get it done since it could be a clogged filter.

 

[ImperialCrown]

The 545RFE has 2 filters inside. There is the flat sump filter and there is a mini spin-on filter above the valve body. Change both.
The transmission isn't actually sealed, but you will need to come up with a fluid level measuring 'dipstick' and follow the fluid check procedure that is dependent on ATF+4 temperature.

 

[Guest]

OK, thanks for the help. Time for a fluid change.

 

[ImperialCrown]

This thread is almost 3 years old?

 

[MoparNorm]

This thread is almost 3 years old?

LOL! Did he really wait 3 years for an answer???