View Full Version : 2001 f250 superduty tranny slips at anything more then 1/2 throttle

January 20th, 2019, 12:09 PM
I have a 2001 f250 superduty. 5.4l 4x4 with 4r100 tranny. Transmission started slipping at anything more then half throttle. Tried tranny flush and filter. this made no change. note that the tranny fluid was still red when removed. figured after the flush i would just get the tranny rebuilt since the truck has 190000 miles. Put rebuilt tranny in and still have same issues. cooler and lines were also flushed out very well before new tranny went in. If i drive the truck like a civilized person (under half throttle) the tranny will go through all the gears and shift fine. if i put the pedal to the floor the rpms go way up and truck barely moves forward. mainly slips real bad in 3rd gear but has slipped a few times in 1st. also going from 2nd to 3rd gear you have to let off throttle for it to shift. Truck shows no check engine light. but note that even when the truck has spit a spark plug, the check engine light did not come on. I know the truck does have a bit of a misfire right now. could this be it? maybe tps sensor or pcm? trans fluid is mercon and is filled to correct level. new torque converter was also included with tranny.
any help would be great because i have no idea where to go from here. Thanks!!

January 20th, 2019, 07:45 PM
Have you scanned the OBD2 for codes? Your CEL is probably burned out.

The Bone
January 21st, 2019, 02:32 PM
Did the rebuilt transmission have a new converter with it?

January 21st, 2019, 02:43 PM
Did the rebuilt transmission have a new converter with it?

Sure looks like it......

new torque converter was also included with tranny

The Bone
January 22nd, 2019, 10:26 AM
Sure looks like it......

Ya i missed that last part

January 22nd, 2019, 11:36 AM
Could the TBPS act up causing something like that to happen under hard throttle? It sure sounds like this is a computer issue to me.

April 8th, 2019, 10:52 PM
Did you check line pressure in park then through the gears with wheels chalked and in idle.there is a port to test from on side of tranny. Need a gauge that'll read up to five hundred psi just in case.