Automatic transmission won't shift properly at 55MPH. Works fine at 54 MPH. Transmission experts are stumped.

[haloram]

I had the automatic transmission totally rebuilt in my 2002 Ranger 4x4. I went to make a pass and kicked it down and the tachometer shot into the red and at the same time, the tranny wouldn't engage, like it went dead. A second or two went by and it finally engaged. I took it back to the tranny shop and they don't know what's causing the problem. What's really weird is, they figured out it shifts fine at 54 mph, but at 55 mph it goes dead or slips for a second or two. They've been in business for over 40 years and have never run into this problem. Nothing comes up on the codes either. Any help would be greatly appreciated.

 

[R A N G E R]

Transmission shift modulator valve? If its old school, see if it's adjustable inside where the vacuum port is on the trans then make sure the metal round rod inside the end of the unit, behind that screw is the right length for your application. screwing it or a longer rod is longer drawn out shifts and screwed out is faster shifts at lower speeds. look up how many turns it should approx. be screwed out as well.

 

[rusty ol ranger]

An 02 is totally electronic shifted.

Your speedo working fine?

What were the symptoms before the rebuild?

 

[SenorNoob]

Good call on the speedometer. Sounds like the signal is getting screwed up some how. Or a glitch in the ECU? Bad capacitor?

 

[haloram]

It turned out to be the transmission valve body. He put in a used one from another truck that he has on the lot. It's a lot better now. If I floor it 3/4 it works perfect, but if I put the pedal to the floorboard, the engine still races a bit before it grabs. A new valve body is over 400.00. I'll have to call the guy and tell him it ain't working as well as it should be. Seeing I got my truck back, my guess is he's expecting me to just live with it. Thanks for all the replies.

 

[00t444e]

Swap a 5 speed into it.