dont know if any of you have ever encountered this, but a few weeks ago i was driving around town, and when i started slowing down i heard a grinding noise, it didnt start until i got below 35 mph. I decided it would be a good idea to try to head home and about 5 miles down the road, my truck quit pulling all together and made the grinding noise in all gears except park and neutral. I got the truck home and tried it the next day, and it went into gear with no grinding or anything, i drove it about two miles and same thing happens. i parked it for about a week and still the same thing, it seems like it just does it when the transmission warms up. if any of you have experienced this problem or have suggestions i would appreciate it. btw its an 84 f150 with c6 tranny

 

If its 4x4 you could also have a transfer case problem.

 

hmm havnt thought about that