Greg.hall

1990 Ford F150 2wd 5.0


with 5 speed OD tranny I believe it’s an M5R2. So i was driving in 5th and all of sudden my rpms shot up and my truck was just coasting. I tried getting into any gear while coasting to the side and nothing. Stopped, and after a few tries i was able to get it into 4th gear and drove it home in 4th. I could go into any gear and release the clutch and the truck wouldn’t stall, except sometimes if i put it in 4th it will stall when i release the clutch. So i replaced the clutch kit, flywheel, rear main seal, throw out bearing, and pilot bearing. Same thing when i put everything back together. So i then took off the shifter cover and looked into the tranny. It looks like the input shaft gear is gone, it’s just smooth where the gear is supposed to be according to pictures online. There are chunks of metal in the case but it doesn’t look like any of the other gears are chewed up bad. My question is why would it go into 4th if the input shaft gear is gone. Sorry for my ignorance. I really need some help here. Also do i have to take the entire transmission apart to replace the input shaft or can i somehow get it out without taking out the countershaft and all that. I put a picture of the gears. Please somebody help.

88xlt

I'm not sure what gear you lost, but the reason it still drives in 4th gear is that 4th gear is direct, the shaft goes straight through the transmission. Unless you can get the parts and someone to work on your transmission you may be better off getting a rebuilt or possibly good used transmission. If you get a different transmission, keep in mind 2 wheel drive and 4 wheel drive transmissions are different. You would also need one from a 1988 to 1991 truck so you have the speedometer drive gear.

The same thing happened to my '88 F-150 4X4 about 8 years ago. I didn't realize I still had 4th gear so I needed a tow. I got a rebuilt transmission off Ebay. Good luck with your truck.