96 4x4, manual trans. Wants to kick out of first, and when shifting into 3rd I have no gear. Doesnt grind, just goes in as though it were neutral. Any ideas?

 

Which transmission do you have? Does the shifter feel sloppy? The M5OD has a shifter bushing that is known to disappear over time. Search youtube for M5OD shifter bushing and you should find videos showing how to fix it. Parts are cheap and it doesn't take long to do. If you have an FM145/146, you might have more difficulty fixing the bushing. It's part of the shift lever so you're most likely looking at a trip to the junkyard.

Some model years of the M5OD also have a known 3rd gear synchro problem but that wouldn't explain the issue you're having with first.

Have you ever changed the tranny lube?

 

M5OD I believe. From what I've gathered so far the M5OD was the only transmission coupled with the 4.0. Would this shifter bushing only affect the one gear? Also, would a bad synchro eliminate a gear entirely? I'll hit youtube now for the bushing info. Thanks! As far as the lube, haven't had the truck long, and never checked it.

 

A broken sycro wouldn't eliminate a gear, it would make it hard to get into that gear though. If all the syncro teeth were gone from the gear, or the slider was bad worn, then no gear. Jumping out of 1'st could be from a bent fork, worn first gear syncro teeth, or the center main shaft bearing is bad enough to let the main shaft slide forward far enough that it won't engage.

 

my '93 lost 2nd gear about 10 years ago, was hard going in and out of 2nd, then one day-no 2nd at all, just a extra "nuetral" postion. i got a rebuilt M5OD for 1,100 and 100K miles later it is still going. the original transmission had only 80K when it had its issue, i think the cause was low fluid level due to leaking shift rail plugs. id sy its time for another transmission....