Torque Converter Shudder
 

I am having a minor problem with my 05 F150 Lariat. Under light acceleration going up a slight grade the truck sometimes shudders (vibrates?). If I let off the gas or accelerate slightly it stops. At first I thought it was a feedback loop with the electronic throttle so I had the dealer reflash the computer but that didn't fix it. I've noticed that it happens right about the time the torque converter locks (looking at the tach) and I'm sure it has something to do with torque converter locking up and then disengaging continuously. Funny thing, it seems to happen frequently on the same hill at the same speed. Anyone else with a similar issue and what was done to fix it?

Quick question. Do you have a limited slip rear end? If you do, this could be a problem with the clutch packs on the LS unit.

Had problems with TCS (Torque Converter Shudder ) on my '97 Mustang.Didn't know what the problem was but the symtoms were as you said, in between 35 - 50 mph it would act like it didn't want to go into lockup. Took it to a tranny shop and they wasnted like $800-$1600 to fix. Car had 101,000 miles on it and so I started reading here and some other investigating the symtoms on the net. My conclusion (and the cheapest) was to just change the filter and fluid, but according to what I read use only the Merc V trans fluid. I did and the shutter is gone. Hope this helps!:)

tonyw4z1l
Is the vibration between 45 & 65 mph and does it vibrate more when pulling a load or trailer at those speeds? Can the vibration be felt in floor next to the gas pedal area and the center console?

Speed is probably in the 40 - 50 mph range. Doesn't feel like it's coming from the tranny hump, it's more like a jerking motion or a bad miss in the engine. Definitely not towing anything.

Quick question. Do you have a limited slip rear end? If you do, this could be a problem with the clutch packs on the LS unit.

Yes

Have a F-150 4x4 Lariat LS does the same thing. Shakes the truck pretty good but if I gas it the problem goes away. Definitely agree it is a torque converter lock-up issue. When it happens I am going up a hill about 42 mph and letting the RPMs drop to come a stop. Sort of lugging it because the RPMs will start to drop but instead of a down shift I get the shudder. Keep the revs up or turn off the od and the problem goes away. I agree that changing the transmission fluid and filter can eliminate a shudder, eliminated a shudder on a 95 Mustang by flushing the transmission but my bet is that it will not help here. Have to ask the wife about it. She a tech at the local Ford dealership.

dirtyharry I think you nailed it. When I back off the throttle it happens more readily but I haven't tried switching off the OD in mid shudder. I can't imagine a tranny fluid change will fix the problem...its a brand new truck. I've noticed that the fluid level is down a bit though.

The best way to road test for a TC shudder is as follows:

Get the truck to the speed and conditions that it shudders, and try to make it shudder as much as it will. When you feel the shudder, lightly tap the brake pedal, just enough to make the brake lights come on for a split-second.

This will make the TC unlock. If the shudder disappears, then it is the TC lockup causing the problem.

I have the same problem in my 95 t-bird with the 4R70W. If you just tap the brakes when the shudder starts, the TC will unlock and all is smooth. I then give it more gas to make it lockup at a higher speed and rpm.

I seem to have the same problem which cant be resolved

Me too
 

My FX4 has a shudder when it downshifts out of OD going up a hill. It feels like I am running over small speed bumps on the right rear of the truck. The dealer flashed my computer to no avail. Hope you guy figure it out.

I have an 04 XLT 4x4 with 20,000 miles; and it started doing that shudder this morning that you all are talking about. I just upgraded the tires day before yesterday from 255/70's to 275/70's, but that shouldn't be the problem.

Same problem here just started at around 6000 miles. Taking my truck to the dealer this week I will post the results.

My friends '94 TC had to be replaced because of the shutter taht you are alking about.

Good point there. I just test drove an 03 Expedition, and experienced the shudder. What I did was manually turn O/D off, and it went away. I could not get it to duplicate the same shudder if I had O/D off. Where I was getting it to shudder was around 55 - 65 with a slight load, and giving it a little gas, but not too much to downshift. It also did it when I went down in speed from 70 on an offramp, then maintained around 55 for a little bit on the offramp.

The Expy has aroun 34K. Think it is a torque converter issue, or a fluid change. Do not know if it is original fluid or not.

Truck in for service on Wednesday 01/26. Rear diff. clutch packs replaced. 200 miles later still no shutter. :)