2002 F 350 suddenly stopped pulling after I stopped at stop sign.160K miles. 7.3 w/AT. Had to rev up for slow roll.Truck would barely roll as though brakes were on or It would suddenly engage and seem to be working right, as though the torque converter wasn't locking up. Am using a Banks torque converter. Tried to reverse, made strange clacking noise and jumped around. Drove forward and reverse, "clacking" stopped, started making grinding noise like brakes. Checked brakes. Fairly new and operating properly. Suspect center carrier bearing. Some up and down slack. Tranny fluid is full and clean,

 

Sounds like tranny issues to me. Very similar to when mine went out.

 

The center carrier bearing can cause some vibration, but it cannot cause what your transmission is doing. The torque converter should not lockup at low speeds, the engine would stall if it did.

Revving the engine to get a slipping transmission to move guarantees that the forward clutch is smoked. Most likely the original failure is the seals in the forward clutch.

 

how about the flex plate. sounds like it to me!

 

@ Mark, replaced driveshaft center carrier bearing. Bearing was good but rubber was badly torn. When it was first malfunctioning if felt just like a slipping pressure plate on a manual but then it would suddenly grab and go, but I had vibration and noise. Seems to be functioning properly now. Truck pulls good but still has "rubbing sound, like a brake caliper is stuck. Pulled the diff.. cover since I need to chamge fluid anyway. Evrything looks good. Gonna try to stethoscope the tranny and see if that's the noise source.
Removed all wheels with truck up on stands and all brakes appear to be free.
@gdunn, I don't know what the flex plate is on an automatic.?

 

flexplate for an auto..straight shift is a flywheel...flexplate bolts between end of crank and to torque converter...they sometimes crack around where bolted to crank and worse come apart...never seen it but sounds scarey

 

the flex plate cracked in my friends ford van and made some noises, then they would go away and come back. if it brakes it could throw the torque converter off balance and it may have enough friction to still drive but enough throttle and it may slip

 

I've had scatter-shield blankets on hot rod AT's before and I've seen a few crack up. Never heard a flywheel called a flexplate though. That one threw me. Appreciate the heads up on that. I've isolated the rubbing or growling noise to the first gear I believe. Definitely in the tranny though. Rolling down the road and kill the engine and put the tranny in neutral and the growling stops. Stop and start rolling in drive tranny growls until upshift to second. Stop and re-start with shifter in 1st and tranny growls until tranny is manually shifted to 2nd. It may still be growling in upper gears but it's really loud in 1st. I'll still pull the drip pan and see what I can see around the flywheel with my flex camera and check out my Banks torque converter, but I feel certain I'm due for a tranny rebuild. Hope no hard parts are torn up. Thanks for the input guys.

 

i have never heard of a pressure plate being bolted to a flex plate so I guess we are even
read my post again

 

There is no flywheel on these trucks with an automatic transmission. There is a flexplate in it's place. It's a sheet metal part and it can crack and make these noises.

 

flexplate for an auto..straight shift has a flywheel

 

@ cord812, not to belabor the point but all the old shop manuals as well as the new ones list what you call the flexplate as a flywheel or drive plate. I have nearly a hundred pro shop manuals (not store bought paperbacks) from cars to trucks and tractors, and not one single one of them refers to a flexplate in the index. Flywheels are referenced as such because they were originally heavy wheels used to regulate speed and balance of machinery long before internal combustion engines. With the advent of auto trannys the term was still used as the "flywheel" was lighter but incorporated a heavy torque converter full of fluid flowing equally and acting as a balancing as well as engaging mechanism similar to the heavy manual style "flywheel" with it's clutch disc and pressure plate. They both also utilized a flywheel gear ring to facilitate the use of a geared electric starter. The thinner auto trans "flywheel" is not sheet metal, it is thin plate steel, a totally different metalurgical composition and density. It is not meant to "flex". If it does, it breaks. It is meant to hold the torque converter stable and vibration free or your front tranny seal will always be leaking and your engine and tranny lubricants will break down due to harmonics caused by vibration. So you keep on flexin' and ignore those engineers grinnin' at you while you expound on your prodigous knowledge. I know this is all a bit above your pay grade and the knowledge is certainly a few years before your time, but FYI; proper nomenclature trumps trade jargon in the front office. Also,it's Crown and Coke, 'cause I can comfortably afford it thank you. Thanks for the input everybody.

 

Well I'm impressed but only in the fact that if you know so much ....why did you ask in the first place?

 

Interesting theory, but it's wrong.

Ford calls it a flexplate. You may call it a flywheel if you like.

It is made to flex, hence the name. As the torque converter spins at higher speeds it grows. It grows both axially and radially. The radial growth doesn't cause any problems, but the axial growth would react against the crankshaft unless the flex plate were able to absorb this force. It does this by flexing in the axial direction. If it didn't the force the torque converter would exert on the crankshaft would result in an early failure of the engine's thrust bearings.

 

not to be-little you but the term "flexplate" is an old established term going all the way back to at least the 40's that originally bolted to a "fluid coupling"
and later torque converters.

flywheels are designed to take the stresses of a pressure plate. and a large mass designed.

flexplates do tend to crack as earlier stated and make a racket

anyway you enjoy your books and have a good evening.