problems with my tranny

[jeffgordon24]

i am wondering if any of you had this problem with there truck .Mine is a 91 4*4 king cab with a 7.3lt n/a.while im driving when the o/d engages if im under 50 mph i can use my kick down no problem if im over that the tranny goes into neutral . i replaced the fipl sensor adjusted it .it shifts better but does the same .had it checked by several tranny guys . also while pulling doesnt want to down shift to 2nd . when my o/d button is disengaged light on it seems to still shift 3 times any info would be appreciated thanks jeff

 

[Mr_Roboto]

Try replacing the tach sensor. It is a maintenance part, and when it goes bad the trans gets real goofy. Run long enough with a bad tach sensor and your trans will be toast (ask me how I know!).

"Replace the tach sender on the oil fill housing a big 1" nut with 2 wires. Ford only part Engine RPM sensor E5TZ-17B384-A about $50. You can remove and clean it but usually changed later too. You can test it too, hold it in the air away from ferrous metal, using an ohm meter lead on each wire you need DC resistance between 2000-3000 ohms."

 

[Mont91]

Have you pulled the codes. If you have a 3.55 rear axle you could/should be dropping to 2nd from overdrive at 50mph if pushing hard at all. Above this the tranny would be trying to go to 3rd. With the overdrive off there should be 3 shifts, 1st to 2nd, 2nd to 3rd, TC lockup. What are your RPMs after it shifts down under 50. The E4OD with a 3.55 with the FIPL set up tight shifts from 2nd to 3rd at about 60 mph. When mine acted a lot like yours the overdrive flywheel was roasted from towing in overdrive. I found this after poping the center support snapring, forcing me to rebuild. Are you able to varify no downshift into 2nd by manualy shifting to 2nd?