So to start with i'll let you guys know you'll have to bear with me a little bit. I'm starting this now to get a head start.

My wifes tow pig is having some issues. Its a late 99, cclb, F350, srw, auto with approx 207k. The truck does not stay at our house and is used primarily for towing a horse trailer (around 6k-8k lbs). The issues have only been described to me by her, I've rode in the truck but it has not acted up with me in it. From what it sounds like to me the torque converter may not be "unlocking" when slowing to a stop. Its "lunging" or "surging" when coming to a stop at low speed, from highway speed. O/D light does not or has not flashed according to her and there is not check engine light. It has not died yet like I would assume it would if the converter was locked up and the truck was forced to stop, and it doesn't act up when in park.

I know its not the best info to start with but I'm hoping you guys can give me some things to look for or to do to rule some things out or narrow the issue down before I take it to a transmission shop to see what they come up with. I'm hoping that I can drive the truck when its acting up soon to get my own "feel" for it because I like to do as much as posssible myself before paying someone to do anything. I should also note that we've only had the truck for maybe 10k miles and it has always had that "rattling" torque converter noise at idle that some of the earlier trucks have had, and as far as we know its the original tanny.

Thanks in advance!

 

Rattling/marbles in can coincides with a cracked flexplate...as for the other issue, have you checked fluid level? When i flushed my trans, it acted the same way until the fluid reached the hash marks. I failed miserably, flushing

 

Yeah I forgot to mention that. I have checked the fluid, level is good, looks and smells good as well.

 

Not necessarily...the 99's had issues with the TC's...there was even a TSB and recall at one point. My L99 has the issue, and has had it for going on 40-50k, and my flexplate has been inspected...you can hear the noise come/go as the TC locks up/unlocks.