Transmission/TQ converter vibration or lugging

[bskouby]

Hey all, I have recently noticed something on my 2006 FX4 with 3.73 gears equipped with a Gryphon.

When running the canned 93 performance tune the truck has developed a lug or major vibration at load when running in 4th gear with the torque converter locked in. This happens around 45-55 mph, and has happened on hills and flat surfaces. I NEVER noticed this before I loaded the 93 performance tune. I ran the 87 tow canned tune for a couple of months and never had this issue. I even went back to the 87 tow tune and could not get the issue to repeat.

I recently received my custom tunes (87 performance and 87 tow) so I should know if the problem repeats itself soon...so far it hasn't.

Here are the details.

1. When in 4th with the converter locked I can slowly apply the gas and accelerate from 45 to 55 and the truck bucks like a wild horse (turning about 1500 RPM). Not much fun.

2. If I get really heavy on the gas during the bucking it will come out of converter lock up (or shift to 3rd) and smooth out. But as soon as the converter locks back in it starts acting up again.

3. If I let off the gas and then get back onto it, the problem will go away until it drops back into lockup.

It will vibrate and buck until I hit 55+ and it will then smooth out. This is not a "lugging sound" but rather a vibration or real lug, similar to running a manual transmission vehicle in too high of a gear at low speeds.

I suspect that this has happened in the past, but for some reason the 93 performance tune made it much more noticeable. Anyone else have any insight? I searched through posts here, and some people have alluded to these types of issues, but I didn't find any posts where someone actually figured it out. I do have the TEJF1P5 hex code.

If the custom tunes take care of it, I'm good. But if I want to keep an eye on it while I still have power train warranty coverage. Every Ford Truck I have ever owned (granted, they were all Rangers) had premature transmission failures, my last Ranger the torque converter blew apart while driving. So...needless to say, when I am a bit sensitive to transmission/torque converter issues.