photon53

Time for an update on this shudder problem: Thanks to GBL for the ABS sensor disconnect suggestion. I disconnected the right rear ABS sensor wire and the problem seemed to have stopped. Keep in mind I drive this van intermittently, about 6K miles the first year, and most of that is in town. I loaded the van up to 4600 lbs on the scale and drove 535 freeway miles in one day and had no noticeable problem. Driving back from the same place at ~5000 lbs, Valiant sheetmetal on the roof rack and a ~20 mph headwind in two days the shudder returned and happened like 20 times a day, often enough I had more opportunity to observe. It shuddered only as the tranny is shifting up from 3rd to 4th on fairly level road. A mechanic friend referred me to Geezer Garage in Coburg, Oregon, where Gary put his mobile code reader on and watched as we drove around. He identified the problem as torque converter shudder as it goes into lockup mode. It is going into lockup a little earlier than it is supposed to, so it feels like the 3rd-4th upshift is when it happens. He didn't think it was much of a concern as far as getting stranded or imminent transmission hira-kiri. Gary recommended LubeGard Shudder Fix, a 5 oz. $9 tube of transmission additive. It seems to be working, although only more miles will tell. I have also ordered some LubeGard Platinum ATF Additive to hopefully extend the life of the transmission. Thank you for your good ideas!

GBL, which ABS sensor plugs are you talking about disconnecting? I recently had all four of the wheel speed sensors out while I did the various parts replacements and cleaned them up. I also had the brakes at the wheels apart and flushed the brake system with new fluid and did not see any problems with plugged lines or hoses. Today I raised all the wheels up just to verify that the brakes aren't dragging anywhere, and none of the wheel bearings is loose. Correcting for speedometer error, I have been getting 24+ mph combined town/country gas mileage and also running on I5 at 70 mph with a heavy load, so brakes may not be dragging much. Or should I be doing better on the gas mileage? I have an Adrian Steel commercial rack on the roof and the van needs a wax job. I will carry my infrared thermometer with me and check the rotor temps. Thank you all for your ideas.

I have a 2012 I bought with 135K miles, and no maintenance history. It has this strange grabbing growl/shudder vibration that happens very intermittently and only for a few seconds at a time. I am not aware of any dash lights coming on, and the only OBDII code is that it is unhappy about the signal shape it is getting from the front ABS sensors, but the ABS system is supposed to be OK. This shudder came with the van, and is still happening despite some major part replacements. Between 40-60 mph, normal level straight dry asphalt roads, van empty or loaded with ~1000 lbs, it suddenly feels and sounds kind of like one wheel is running over a growler strip. There is a bit of vibration I can feel in the steering wheel, and the van shakes a little, and slows down a very little bit. But this only lasts for 2-4 seconds and stops. It can happen twice in 20 miles, then not for the next 100 miles on the same drive, or not happen at all for 300+ miles. In zeroing out the maintenance schedule and eliminating all the existing obvious problems, I replaced CV axles, wheel bearings, tie rod ends, control arms, ball joints, outer tie rods, bar links, every moving part in the front suspension and drive train except the struts which seem fine. Motorcraft, Moog, new CSG CV axles; "good" parts. (Note: the Motorcraft wheel bearings were NSKs). I replaced all the rear brake parts and find the rear wheel bearings to spin smoothly with no obvious problem. Flushed in new car juice in all possible systems. This shuddering has not changed at all. I have new Timken rear hubs in my parts box, but I am not certain this is the problem at this point. It does feel like a brinelled wheel bearing might feel, but it happens so seldom... Could this be a brake or two chattered by the ABS, or some weird transmission gremlin? Or what? Profuse thanks to the community for providing such useful information on these vans!

With regard to Beta Don's comment on the appearance of the Mercon LV fluid: "My old fluid didn't look all that great after only 25,000 miles - More brown than red. It didn't small that bad, but it wasn't nearly as pretty as the new stuff. I was a little surprised . . . . I thought with so few miles, the old stuff would still look pretty much new. I'll go 50K with the synthetic and change it again." This Ford mechanic says that is normal for this fluid, for what it's worth...