1994 K1500 4.3, 5 speed manual popping out of gear

[gmguy1966]

Hello all, I'm the latest new guy. How yall doin?

My son has a 1994 K1500 4x4, with a 4.3 and a 5 speed manual. I thought he was imagining things until it happened to me. Three times now. The truck will pop out of 1st gear violently, but not every time. It seems like if you are taking off from a dead stop on a slight incline, it will do it almost every time. It also wants to pop out of 3rd gear. Sometimes when shifting from 2nd to 3rd, even with the clutch pedal pushed all the way down, it seems like it wants to grind going into 3rd, and then pops out.

I have researched several different forums and this one looked like the best one to join. I also searched this forum but couldn't find any past issues like this, so sorry if this is a duplicate.

From looking at the older posts, it looks like I am definitely going to have to figure out which 5 speed this truck has. Could be a Getrag or a Borg Warner or ??? Also varies in regards to the right oil/tranny fluid? I would have though 80/90 weight gear lube, but I saw some posts indicating it might take some form of Dexron or sythetic or syncronizing (sp?) fluid/oil? Could it be the same stuff an AWD Astro van takes in it's transfer case?

Anyhow, thanks for reading this post. C ya, Joe

PS: The truck only has 91,000 on it. We have owned it for a little over a year. Bought it from original owner and he provided extensive maint records, including a new clutch and some sort of transmission work (something about having 2nd gear replaced??). I told my son to get the 5 speed because I thought manual trannys were more reliable than automatics, but maybe not with this model???

[RahX]

Sounds like the detents that hold the sleeve in gear are worn out. Your best bet is to either deal with it, have someone go through the trans or just get a junkyard special. Most manual trannies are pretty reliable, but not 100% bulletproof.