I recently purchased a 2000 excursion with a 6.8 v10 4x4, had the usual problems that i have been fixing but now the transmission is acting up. First after driving it around for a while the front pump seal started to leak, as a temp fix i used atp at-205 and it actually stopped leaking for time being till i have time to pull the trans. But then i got curious if the trans temp was getting high to make it fail as well as since i bought the truck it felt sluggish from a dead stop but tons of power after moving. So i have been hooking up a otc genisys scanner to it every time i drive it. It has been reading that it always starts in 2nd second gear, i cant even manually put it in to 1st and as it shifts on the highway it says 4th gear then shifts and says invalid. Sometimes it shifts hard and sometimes soft like a slippage, doesnt matter on trans temp. Now for the temp it stays around 190-205 for about a hour city driving then it starts to go up to 230-240. Also the torque converter never engages and scanner only reads 0% for it. Then i pulled codes from the trans reading p0781 1-2 shift error and p1744 tcc system performance/stuck and the trans control od light does flash. I feel the high temps are from the torque converter not engaging. Is this a symptom of a easy fix like swapping soleniod pack from the pan or is this internal damage or wear and needs a rebuild. I would like to get through the winter and pull the trans in the spring to at least do the front seal, but plans never go to plan most of time. Any help
Or experience on this is greatly apprecitated.

 

Is there no one out there that had both of these codes come on at the same time?

 

The two codes might be related, but are probably separate problems.

Not being able to even shift manually into first gear is probably a stuck shift valve in the valve body. It is possible that it is a bad solenoid, but that should also set a code for a bad shift solenoid.

The no lockup can be a different stuck valve, and I think this valve is in the pump body. It could also be a bad torque converter, or a worn out seal. Not the seal that is causing your leak, this seal is on the input shaft.

 

Mark, thank you for you response, it is greatly appreciated. Do you think it is worth a trans flush to try to unstick any valves hung up, or since i have to pull the trans anyway for the front pump seal should i just drive the way it is locally for short trips until next spring? What i am also considering is buying a trans in need of a rebuild i found for 50, i know already its not a 2001 with the mech diode, but im waiting for a response to find out if it is a diesel or gas housing or a pwm or non-pwm. If it is the right one i will buy a atsg manual and attempt a hd diesel build up in the gas housing with a billet converter and rebuild the pump housing, and convert to the 6 pinion od plantery. At least then i can work on it during the winter in the garage until it gets warmer to pull the trans. Also how do u feel about transynd atf in a 4r100, i only ask this cause i can get it for very low price and its only a long interval syntheic dex 3 from castrol, or is there a specific reason for the mercron in a ford trans?

 

DEXRON III and MERCON are so similar that you can use either. Almost any fluid that had a MERCON rating also had a DEXRON III rating.

A trans flush might fix it. I wouldn't hold my breath, though. If the trans has to come out anyway freeing up the valves isn't much more work.