You still have the original LT77 tranny in your truck. I'm assuming your truck is an NAS 94, and these came in the 93/94 NAS 90s and 110s. They're known for the syncro issue, particularly in/out of 2nd, and most were swapped under warrantee to the then newer R380 by LR dealers way back then if the customers complained, or have been swapped to R380s since.
My 94 had the original LT77 with the same issue when I bought it, and I got used to it and was just careful and patient with shifting. That being said, I did keep my eyes open for an R380 opportunity, and after holding onto one for a long time, I recently had it installed and it's nice to have a solid and smoothly shifting tranny.
Auto swaps are common but expensive, but I appreciate and have fun driving the manual, and I also have an auto 97. You drive a D90, the ultimate man ride. Why remove the man pedal?
You can rebuild (or have rebuilt) your LT77, but if so, do a complete rebuild. You can also swap up to a good new or rebuilt R380 (my recommendation) and this will be in the same price range for a stronger and less grind-prone tranny.
Just my 2c.