Todd Miller

Hi all,

I'm new to the forum. I have multiple (5 total) Ford trucks in my fleet as well as personal trucks.

My question pertains to a 07 F150 XL 4x4. Auto trans. Very basic truck. But, I lifted it 6" and put it on 18" XD Monsters (-12 offset) with Nitto Grapplers last week. 119K miles. Bought used 3 weeks ago.

The tranny has a a glitch. Just don't know if it's shot or something can be more easily rectified than replacing the whole transmission. It has the overdrive button on the end of the transmission lever, on the column. When I'm driving under limited acceleration between 45 and 55 MPH, the truck bucks continually and hard, as if it's trying to make up its mind to shift in or out of overdrive. If I click the overdrive button OFF, the problem virtually disappears. I do a lot of city driving in this truck so it's annoying. Once I give it a little more throttle, even with the overdrive in its normal 'on' position, it seems like it makes its mind up and works...better. On the hiway, it operates fine and I just leave the overdrive on all the time....most of the time. Today, at just under 65 MPH, it started doing the same thing with the OD engaged.

Any suggestions on a fix for this? Anybody have an idea what the problem is? Where to fix? I've had half a dozen transmissions replaced in my fleet over the years. None are cheap and it's always a point of concern.

tomtom52

It's called torque converter shudder. It's a chattering of the clutch on the torque converter not staying engaged. Proper fix is new converter. Cheap and easy and the one I did, Dr trannys instant shudder fix from O'Reilly. Its a friction modifier to make the fluid sticker I think. Anyway worked for me and came recommended on some other boards. Just Google torque converter shudder.

primalurges

Friction modifier may for a few months. At 115k it's a tough call because you may replace torque converter and need a transmission 10k miles down the road anyway. It does however sound like a torque converter.

VTX1800N1

What you are experiencing is often engine misfire, even though it feels like the transmission. When were the plugs last changed?

Todd Miller

Hey all,

Thanks for the helpful replies. VTX1800N1, I know what you mean about it possibly being misfiring but I am relatively certain that's not it. Especially in light of the fact that it is virtually eliminated by disengaging the overdrive button.

primalurges and tomtom52, it is a tough call. It's actually 119K miles. But, to me, if it allows me to bring it along for another 10-20K miles that's a good trade. So, I'm gonna give the shudder fix fluid a shot and see what happens.

THANKS AGAIN, to all of you. I'll let you know how it goes.

VTX1800N1

The shudder going away when disabling the OD is a classic sign of misfire. It's harder to light the mixture at low RPM high torque demand conditions, both of which are present at 45-55 MPH accelerating in OD. Shifting out of OD eliminates those conditions.

lewissa81

I'm in agreement with VTX1800N1. I would chase a misfire before I put anything in the tranny. How old are your plugs and boots?

Todd Miller

lewissa81 and VTX1800N1....looks like you guys are on the right path. I'm gonna change plugs and boots and see if that helps.

Shudder fluid did nothing. In fact, the problem has likely worsened in the past couple days. It is now noticeable as high as 65 MPH in OD on the hiway.

So, whadda you guys think? Just tune it up? New plugs?

yknot

My truck did the same exact thing as yours. New plugs and boots and it went away.

lewissa81

Yea, start with plugs and boots. Maybe throw in a fuel filter because they're cheap but important.