Here's a riddle that has me stumped... If I'm at a dead stop, like at a stop sign, and I turn hard to the left (primarily) my front end shutters or vibrates heavily, almost like my front wheels are locked and bouncing sideways on the pavement. I thought maybe my wheels were hitting the frame, but there are no rub marks either on the tires or anywhere on the frame. Sometimes it does it when I'm not hard over but on a lesser turn. It's worse when I'm on a hill. Sometimes, it'll happen on a right turn but not as often.
Several times I've had mechanics crawling under the vehicle to look for loose joints, bushings, etc. to no avail. I've replaced sway bar bushings (totally shot), but that didn't help. I was recently able to demonstrate to the Ford mechanic, and he felt it, but when I left him with the vehicle, he was not able to replicate it for his tech. He's had it for a week driving forward, backward, several times but no replication. I'm sure when I pick it up tomorrow, it'll shudder it's way out of the dealer's lot.
It's a 2006 Concourse (2004 E350 chassis)...any thoughts
Vibration on turning
Re: Vibration on turning
Those are the exact symptoms I had at one time (including hopping, worse on a hill because its more weight being pushed, and even to the turn left being much worse than right).
It is most likely the rear differential.
After I had been dealing with it for a month or more, and tried a few places, I stopped at Donco in Austin, TX. The guy there diagnosed it in all of 2 minutes as he stood outside in the parking lot while I drove around him to the left, and then fixed it in a couple hours (plus waiting another hour or two, because he said things had to settle or something and it was important not to drive it too soon). I was full-timing it and just passing through, and after nearly 12 years I still remember how nice, and competent, that guy was.
Yes, I know, it sounds like it's coming from the front (did to me, anyway), but it is almost certainly the differential binding up. It had started happening for me just a few thousand miles after I first bought my Concourse used.
The mechanic said whoever last worked on it had put in the wrong fluid (he checked after draining it). He took things apart and did a thorough check of the parts (ring and pinion gears), and said I was lucky, no damage had occurred, yet.
Fluid on my 2000 Concourse on Ford E350 was 75W140 Syn Gear Lube and adding Limited Slip Additive (very important, assuming you have Limited Slip).
It is possible the Additive was what was missing from the previous service on mine, as according to what I've read most RV's on the Ford E350 do not have the Limited Slip, so mechanics often will not realize Chinooks generally do.
Be sure when you take it somewhere that they are competent to open the differential, drain it, inspect it, and put it back together.
A few years ago I had a leak of the fluid, from an incompetent tech putting on new tires (he messed up a seal on the axle there, which I believe is part of the fluid in the differential), and on taking it to be fixed, I found that quite a few shops do not want to open the differential (or feel unsure about doing so), even just doing a fluid change. Which I wanted, seeing as so much of the fluid had drained, though the tech wanted to just insert the fluid in through the axle so he wouldn't have to risk opening the differential case. Apparently it's not that easy making sure they don't mess up the gear/pinion/whatever sitting correctly, and getting things back correctly!
Good luck,
Bob
It is most likely the rear differential.
After I had been dealing with it for a month or more, and tried a few places, I stopped at Donco in Austin, TX. The guy there diagnosed it in all of 2 minutes as he stood outside in the parking lot while I drove around him to the left, and then fixed it in a couple hours (plus waiting another hour or two, because he said things had to settle or something and it was important not to drive it too soon). I was full-timing it and just passing through, and after nearly 12 years I still remember how nice, and competent, that guy was.
Yes, I know, it sounds like it's coming from the front (did to me, anyway), but it is almost certainly the differential binding up. It had started happening for me just a few thousand miles after I first bought my Concourse used.
The mechanic said whoever last worked on it had put in the wrong fluid (he checked after draining it). He took things apart and did a thorough check of the parts (ring and pinion gears), and said I was lucky, no damage had occurred, yet.
Fluid on my 2000 Concourse on Ford E350 was 75W140 Syn Gear Lube and adding Limited Slip Additive (very important, assuming you have Limited Slip).
It is possible the Additive was what was missing from the previous service on mine, as according to what I've read most RV's on the Ford E350 do not have the Limited Slip, so mechanics often will not realize Chinooks generally do.
Be sure when you take it somewhere that they are competent to open the differential, drain it, inspect it, and put it back together.
A few years ago I had a leak of the fluid, from an incompetent tech putting on new tires (he messed up a seal on the axle there, which I believe is part of the fluid in the differential), and on taking it to be fixed, I found that quite a few shops do not want to open the differential (or feel unsure about doing so), even just doing a fluid change. Which I wanted, seeing as so much of the fluid had drained, though the tech wanted to just insert the fluid in through the axle so he wouldn't have to risk opening the differential case. Apparently it's not that easy making sure they don't mess up the gear/pinion/whatever sitting correctly, and getting things back correctly!
Good luck,
Bob
2000 Concourse, Ford Triton 6.8 V10
Re: Vibration on turning
Thanks Bob! I should have known better. My F150 would chatter on turns, so I had the rear dif flushed and refilled with anti-slip and it seemed to have fixed it. The Chinook was a more severe shutter, but then it's bigger equipment. It also makes sense why the symptoms are sporadic. I'll have the dealer change out the fluid. It has 140k miles on it and I'm probably looking at original fluid.
Thanks again! I makes perfect sense to me. Too bad the three shops I took it to couldn't figure it out. You apparently found a smart one.
Thanks again! I makes perfect sense to me. Too bad the three shops I took it to couldn't figure it out. You apparently found a smart one.
Re: Vibration on turning
Just to follow up: I had the shop service the rear dif with a complete flush and replace with new friction fluid. I haven't felt any shudder for the past two months. Thanks for the advice!