Rough Shift

[Drew Lonker]

I'm having a rough shift at about 45 mph in my 01 4x4. Its like it doesn't want to downshift. It will start to shift then hesitate before downshifting. After the downshift I can feel a vibration in the gas pedal. I had the transmission fluid and filter changed about 14k miles ago and changed the rear differential fluid today, still does it. If I get on the highway and get up to 65 or so there is no rough shift or vibration. Its only when I drive around 45. Truck has 105k on it. Any ideas would be great!

 

[Vic Sorlie]

Checked trans fluid level? Even though you had it changed recently, verify level.

 

[Drew Lonker]

Fluid level is fine. Right I'm the center of the dipstick. I'm at a loss

 

[John G]

Could it help to disconnect your battery for a while, then reconnect, to make whatever controls the tranny to "forget" what it has learned and start over?



Years ago I had an up shifting problem at about 50k miles. I was told on this forum that it sounded like slipping. I talked to a a tranny shop manager and he wanted to quote a rebuild without even a test drive. All that turned out to be bad advice because my problem, went away by itself. Never had to spend a cent, and it is still good.



My theory is the tranny somehow "learned" something wrong about the time to shift, and it eventually learned something better, but maybe I could have speeded the process by disconnecting the battery. Maybe I'm wrong about all that, but it couldn't hurt to try.



Also, a vacuum leak under the hood can sometimes cause trannies to shift badly. I once heard of someone who purposefully disconnected a vacuum hose so the car shifted badly, then took it to a tranny shop and the shop wanted to rebuild it! It was a test to demonstrate that the shop was crooked. Anyway, check for a leak if you can.

 

[swshawaii]

Trouble codes?

 

[Drew Lonker]

I tried unplugging the battery to reset the computer but it didn't seem to help any. The check engine light isn't on so would I still get a code if I took it to advance and have them read for one?

 

[Duane Foster]

This may not help as you're having a problem at one speed, but I cleaned the MAF on my '01 a few weeks ago and doing so corrected my shift points. The truck was really sucking gas, and staying in each gear too long. I cleaned the MAF and disconnected the battery for about an hour, and now mileage is much better and it shifts when it should. I suppose I had to push the accelerator more with the dirty MAF, so it was staying in the lower gear like I was constantly trying to accelerate even though I was really cruising at a steady speed.

 

[EddieS'04]

Also this being an '01. Some of the early tracs had a bad seperator plate with the valve body. It usually caused a bad shift from 2 to 3. Might cause other problems, if not replaced. Could be shift soleniods sticking.

 

[Yardsale]

I think it's not the 2-3 shift flare (slow, not rough, upshift), but read on ...

 

[Drew Lonker]

Yeah it only happens on the downshift. The delay in downshift only happens every now and then its the gas pedal vibrating that annoys the heck out of me

 

[Yardsale]

Any noises? Can you feel the vibration on the floor or elsewhere?



Other than the pedal mount, the throttle cable is the only connection to the vehicle. Maybe the throttle plate is vibrating possibly due to some backfire or flow issue and that is transferred to the pedal (really a stretch on this hypothesis).

 

[swshawaii]

Won't have any effect on your downshifting issue, but check anyway.



http://www.mysporttrac.com/shared/msgboard9e.asp?BOARDNAME=MSG&VIEW=954210&sitename=mysporttrac

 

[Drew Lonker]

Thanks for the help. I checked the wires and it looks like the gas pedal was vibrating because the wires were touching the spark plug wire.