I have a 96 F150 5 speed manual about 150,000 miles has a new clutch, throwout bearing, flywheel was machined same time as clutch replacement. Drove about 300 miles the other day through a mountain pass; ran great no problems until I down shifted to 3rd gear and it would not come out of 3rd gear. I tried yanking it out with all but my arm coming out of socket...just didn't want to move. I costed while in 3rd gear with the clutch pedal held in for about a mile. Tried many time to remove it from 3rd gear with no luck. Then all of a sudden with little effort it came out of 3rd gear with the clutch pedal engadged. continued about 100 miles to our destination with no other issues until; while the clutch pedal was out (engadged) I started hearing a cluncking noise; like gears where hitting eachother. This only happens when the clutch is engadged. While driving it down the road at any speed with the clutch engadged the noise continues relative to speed, but once I depress the clutch the noise will wind down even with the motion of the truck. Took a look/listen to the under side of the truck and I believe the noise is coming from the back portion of the Transmission. Anyone have an idea of what this could be. Is my transmission going out? Thanks for time. Have a good day.

 

I think I have the Mazda M50D Transmission? On the door decal under Trans it says "M". On the transmission tag itself it has a label of the following:
F1TA
GC
C183793

Thanks for the help!

 

Have you been able to recreate the situation where it got stuck in 3rd?

I have had nothing but problems with the my mazda tranny. But nothing that sounds to similar to yours. Sometimes the force on the gears can hold them engaged and keep you from shifting especially if the clutch isn't fully releasing. Do you know if the slave was replaced with the clutch or if the line was disconnected. If it wasnt replaced, they have a tendency to go out with the clutch, and if it was just disconnected it might not have been bleed correctly.

The sound your describing from the rear of the tranny doesn't sound good. How loud is it? After everything i put mine through it never made any noise. I would drain the fluid look for metal, then maybe pull the top cover of the transmission off. It pretty easy, just remove the seats, shifter, pull the carpet back and remove trans tunnel and you can easily get to the top of the tranny. Open her up and see if you can see anything wrong.

Is the truck a 2wd or 4x4?

 

It is a 4X4. It has not stuck in a gear sence. I did replace the slave cylinder at the same time as the clutch. This was about 2 months ago. It's deffinatly a noticable sound. If I didn't know any better I would have said it was the u-joints going out. That is what it sounds like. But, I knew to check that...the obvous noise is coming from inside the trans.