i hv a 92 W350. with some mods. in the past few days iv notice that my truck wont stay in 5th gear if you hv your foot on the peddel its fine but still will pop out now and then. but soon as u let off she kicks out. dk whts wrong. i thought barings but i put the case in N and trans in 5th and no noise so barinigs and gear is ok i think. i think it may be the fork not sure some 1 let me know wht coud be the prob. id hate to buy another trans

 

Sticking the t-case in N takes the load of 5th gear. I'm thinking 5th gear is wore out, in which case, I'd rebuild the entire transmission.

 

when mine did this it was due to improper shimming sounds like **** is wore out and your getting a little slack the reason you only have a prob with fith is due to the load and speed that is put on the tranny a rebuild is cake read this https://www.dieselbombers.com/1st-ge...de-getrag.html

 

first signs of the tranny going sorry man