My trans did the same thing you discribed. After driving to try and get it home it started working. One week later, backed out, no forward gears. Finnally got it to move in 1st, then know trans. Got it to john woods, now all is fine,

Chet

 

Thank you Mark and Cord812 for your insight and experience on this matter. @ Mark: So as the torque converter "grows" the "flexplate" allows movement to keep the crankshaft "centered" on it's thrust bearings? Is there a chance that an aftermarket torque converter is not compatible with this "flexplate". Banks Engineering is supposed to have developed this torque converter to work within Ford specs. If the flex action is relieving stress against the thrust bearings is there a chance it is overloading the tranny in some way? If this were your tranny and you were rebuilding it would you consider a return to a stock Ford TC? One more question: The Banks variable electronic stall control was recently removed from the vehicle. Did that render the default specs on this system moot? I know this sounds like a silly question but the aftermarket tc is supposed to be subject to Ford specs at the low setting and I have felt for some time that it was engaging at a higher stall than stock.

 

@ Bonanza35, I have been driving these things since '84 and this is my first time to encounter a tranny problem.Thanks for your input.

 

I believe you are correct. I wish I could figure out why and what the failure is so I can avoid going through this again. Mind If I ask you what the HD trans is about?

 

No, there is no chance it is overloading the trans.

I would not consider that.

I have never heard of a device like this. I can't imagine how it would work. Do you have a better description of it, or a link to a webpage that describes it?

Typically aftermarket converters are not subject to any of Ford's specs. They design whatever they want. Most of the time the converters are made from stronger materials than the stock converter, so they will grow less than the stock converter.

 

Am getting info on torque converter together. Will forward to you when I have it all. An aftermarket shop (highly rated) installed Banks gear when truck was new but a Ford dealer tech removed items recently while tracking down a short in the fuel system. Thanks

 

I had my tranny rebuilt with HD internals and a split overdrive.
I can go back through my old emails if you want the brands and details on it but the guy warrantied the tranny for 36K miles and 2yrs. so long as I didn't breach the 500HP range. $2500 for the pacage... I'm not gonna complain.

Only reason I had to get the info emailed was to get my chip reburned.
As for why.... My tranny was the original and died at about 240K miles. I figured with the abuse it took from hauling...it was about time anyway. When the shop called me they asked if I thing for Chia pets. The drain plug had so many fragments that it looked like a chia pet.

 

What is a split overdrive? I've never heard of that.

 

Why did you start a second thread that is identical to the first? It's confusing. Here's the original with much more info:
https://www.ford-trucks.com/forums/1...l#post11921851

 

Kind of an additional half gear. When I hit about 50 when accellerating normally, it kicks into OD. At 70, my RPMs are about 2000... When I hit about 75 @ 2500... The RPMS drop back down to 2000. Not a lot of change..but enough to give me a touch more MPGs. At least thats what I call a split OD. Could be doing something with the TC... I'm not a tranny wiz...which is why I paid to have mine done and didn't mess with it...Much. Other than trying all gears when it died just to see what I had and didn't have.

 

I didn't know it got the name flex plate due to it actually flexing or growing. I've heard of flex plates being cryo'd. Is this a good idea? I'm assuming this is done to keep them from cracking or breaking.

Drake

 

I dono't know if cryo will help or not. I haven't looked into that for a flex plate.

 

It would also seem make sense that a torque converter, with a a billet cover, would limit flex and be less likely to crack a flex plate. I haven't heard of a cryo'ed one, but a billet flex plate would also be an option to the stock "stamped steel" one.

 

I've often wondered about billet flex plates, but never had an opportunity to test one.

Do they flex less than a stamped flex plate? If so, that should transfer more force to the engine thrust bearings. I wouldn't think that's a good thing.

 

Never used one myself. The stock Ford one is holding its own at almost 200k miles and > 400rwhp. I'll just leave well enough alone.