T/C lock-up

[cnuttgirl]

What are the symptoms of a T/C not locking up? if the lock-up solenoid isn't functioning properly, would a tranny flush with anti-shudder additive cure the problem? would a bad T/C (and or lock up solenoid) damage a tranny?
I have 20,000 miles left on my extended warranty and would like to get it looked at. I have a 4x4 5.4L 99 expy with 68k. with constant normal acceleration, when i hit 40mph (1700 rpm) it sounds like i'm going over rumble strips...at 50 mph (1300 rpm) it does it again. this almost never happens when the truck is downshifting. under hard acceleration (trying to pass) it happens once at 50-55 mph (over 2k rpm). I can replicate this now, on command.

any ideas??
thanks in advance

 

[monsta]

When was the last time you replaced the tranny fluid?

I would shy away from any additives that are not specified by the manufacturer. At least as far as the tranny is concerned.

 

[cnuttgirl]

never have...i have 69K miles on it now. was gonna wait to change fluids at 100K, but if this is a problem...i wanna go ahead and do it...especially if it will make the engine life longer. basically, i'm trying to figure out if i should gripe about the tranny...or go get the fluid changed

 

[Guest]

Could be your clutches slipping that is causing the shudder. Could be the tc. A simple flush won't help. If that is the problem it will have to be replaced.

 

[cnuttgirl]

sorry, what is "it"...did you mean the t/c would have to be replaced or the transmission?? thanks for your reply

 

[monsta]

Your fluid should be changed every 30K. You're waaaaaaaaay over due.

That is probably causing the shudder.

Replace the fluid and see if the problem persists.

 

[Burt]

I had very similar problem. Ford found a bad bearing in t/c to be at fault.
Apparently the bearing would freeze at higher RPM. In my case, it would then overheat, which caused t/c case to crack near bearing. I would find some drips of fluid under vehicle after sitting overnight.
They replaced the whole t/c case for me under warranty.
No problems for 6 mounths now.
You may want to have the t/c bearings checked BEFORE your warranty expires!
Looking at approx. $2,600 otherwise.

 

[cnuttgirl]

awesome thanks...currently had the truck in the shop to have exhaust manifold replaced...they found a mojor oil leak (need new head gasket), and a hole in the transmission tube (dip stick). maybe i can talk them into checking out the t/c bearings while it's up in the air