so took my new-to-me '07 on my first road trip this weekend. all was well until i started playing with the cruise. turns out it works, but when accelerating on the freeway i notice the transmission makes a grinding sound, almost like i'm hitting a rumble strip for about half a second... more of a vibration i suppose. and it's only just before the transmission comes out of overdrive, never any other instance. i'm not sure on the age of the fluid.

ideas?

 

Sounds like torque converter shudder.

 

interesting, i'll read up on it thanks.

and in case anyone is wondering, it's not a jerk or hesitation like a COP or plug is bad, i've had experience with that before, this sensation is nothing like that.

 

my symptoms, almost word for word:

Tranny/Torque Converter Shudder Probs - Ford F150 Forum

sounds like you're on to something mike.

 

If you take it to a good shop like O'neils in Cascade they will be able to hook up to it and tell you exactly what's going on. I think they charge like $80 for the diagnosis though. But they are the BEST in town. It could be as simple as a solenoid hanging up. It may even be able to be re-programmed to be fixed. Maybe the lot you bought it from will pay O'neils for a diagnosis?

 

maybe. i just bought a $5 tube of Dr. Tranny Instant Shudder Fixx after hearing it clears up alot of similar issues. sounds like it's a pretty common 4R75E thing.

truck does have a 30 day powertrain warranty so i'll definitely be keeping an eye on it.

 

If you change the ATF you will fix this.

 

thanks mark! will a simple drop n' drain suffice or will i need to flush? rather not do the latter if possible.

and would you diagnose this as the torque converter shutter i read about?

 

This is the classic symptoms of torque converter shudder.

A drop & drain will change about half of the fluid. That should half fix the problem. Changing all of the fluid should fix all of the problem.

HERE is how I do it. This is written for the E4OD/4R100, but the procedure is the same for the 4R70W. The lines are not as easy to identify. One is on top of the other at the trans case. I don't remember which is which.

 

perfect. so that's still not a "power" flush, i'm cool with that. thanks again.

 

When I change fluid I just remove both cooler lines, let bad fluid pump into the bucket, and have another bucket with clean fluid. Let the truck idle until the stuff going into the bucket turns clean. Shut of engine, reattach lines.

 

How do you add the new fluid? There is no suction in the cooler lines, it won't draw fluid out of a bucket.

 

I have the bucket above, gravity feeds it.

 

I have the exact problem as you described.
Can I ask what brand or name of the friction modifier you used to have solve your issue?

Thank you.

 

Dr. Tranny Instant Shudder Fixx


i haven't put it in yet, so i don't have any results to report just yet.