Tansmission wont shift until high rpms

[flatland freak]

I have a 1995 powerstroke 4x4 with auto trans, it will not shift until 2300 or so rpms at light throttle and I have to almost let off the throttle to get it to shift any lower than that. It shifts into all gears and seems to drive fine other than that. I just bought the truck and have been fixing alot of small things and have now moved on to this. I drained trans and tc and replace the filter and filled with motorcraft mercon V fluid. The fluid and filter change did not change anything but the fluid that I drained out did not look bad or smell bad. The case of the trans looks like it may have been painted grey at some time which makes me think that it has been remanned at some point. The truck has 190k miles. What should I check, I have acess to a snap on scanner and can look at trans info. It will also downshift from 3rd to 2nd and 2nd to 1st when I am slowing down but still on the throttle, like when I am slowing from 55 down to 30 coming into town it will downshift way to soon so that my rpms are around 2k ( not real sure exact rpm but high). Thanks in advance.

[1Dieselman]

Are speedometer and tack working correctly. If not you need to fix them first. Is the truck chipped? Reason I ask is a chip can change shifting points.

[flatland freak]

the truck is bone stock, no chip. I have not noticed anything wierd with tach or speedo, what should I be looking for?

[1Dieselman]

The tack usually works or it doesn't but if the speedometer is bouncing around it's possible that the sensor on the rear axle is going bad. Is the overdrive light flashing? Other than that I would get the scanner and check for codes then drive it in data streaming mode and see if the trans shifts when the computer tells it to or much later.

[flatland freak]

ok, tach works. The speedo I will watch tomarrow and see if it bounces. Am I looking for big bounce or would a small bounce do it and also the overdrive light is not on and the od switch works fine, cruise works also.

[1Dieselman]

Speedo shouldn't bounce at all.

[flatland freak]

ok so this morning on the way to work I could see the speedo bounce2-4 mph around 50mph. Is that enough to cause the transmission to not shift correctly in all gears. I did not notice anything at lower speeds.

[flatland freak]

I pulled codes with scanner and the only code there was (Turbocharger Boost Sensor A Performance). No check engine light though.

[1Dieselman]

No it shouldn't bother it. Did you drive with the scanner hooked up checking when the computer tells the trans to shift?

[flatland freak]

no, i will try that at lunch and see what I get.