Det 1

I've searched the FAQ's but haven't found a description that specifically matches my problem. While towing a 12,000-13,000# trailer we will experience a sudden "hesitation" or momentary loss of power. As another poster described it, it's like suddenly being hit from behind. It's always at speeds between 50-65 and while on a slight or moderate incline. Cruise control may be engaged, or I may be applying a light acceleration. It does not happen under heavy acceleration (I may experience a hard shift then, but I think that's normal). It usually happens when tow/haul has [U]not[U] been selected, but has happened infrequently when in tow/haul. The govenor pressure sensor and solenoid were just replaced, but that didn't seem to help any at all. My mechanic reports that diagnostics indicate the Throttle Position Sensor is OK. The check engine light has not come on and it's not throwing any codes, so if there is anything wrong it must not be monitored by the computer. I read about the APPS reset, and will probably attempt that in the next day or so to see if it helps. After reading some of the threads, I'm beginning to wonder if anything really is wrong, or if it's just the nature of the beast.

Spooler

It sounds like the TC is locking up. It will give an little bit of a blast of acceleration when it locks.

Bye the way, the 04.5 trucks don't really have a tow/haul. When you mash the button you just have an OD lock out. It never goes to 4th gear. Mine never does hence the high RPMs. I only use it if I start to lug the engine or for engine braking which ain't much.

Det 1

I suppose it could be the TC locking up, but would I expect the "blast of acceleration" to occur every time? The symptoms I've been experiencing have been very sporadic and I haven't been able to intentionally duplicate them. The hesitation may occur within the first 15 miles of driving and may not occur again for 125 miles; or it may happen after 50-90 miles and then again within another 40 miles.

I'd heard that tow/haul in this truck was actually only an OD lockout, but it does seem to significantly reduce the sudden hesitation we've been experiencing.

Thanks for the response.

shortbed rv

FYI: If you like you can add a led light to come on when the T/C locks. I have one and later I added the T/C lockup switch. Just splice a wire to #7 pin on the trans and run the wire into the cab splice in a radio shack led and run the other wire to hot ( cig lighter). The light will come on when the T/C locks and go off when the T/C unlocks. Good pictures in the t/c lockup thread. This might help you tell if it is a T/C lockup problem.


BTW: when the T/C is locked your trans will run cooler which can help you towing in the mountains. Lets say you are climbing a mountain and the T/C is not locked You may want to either increase your speed to lockup or down shift to higher RPM to lockup.