The Getrag is German built and was in the 1/2 and some light 3/4ton Chevy/GM pickups from 88-94/95. I say 94/95 because they introduced the NV3500's mid year and 95's can have either or and in 96 is was only the NV3500's.
Here is a post that I replyed to a few months back and has info on both trany's.
Ok, I just did some hunting for ya seeing I know quite a bit about this trany.
Here it is.......Turns out your trany is not the Getrag. GM used the Getrags (5LM60's) from 88-95. Seeing others will be looking at this post I may as well tell everyone what I have found. It is made by Getrag/Muncie (German made) Its used an RPO code of MG5 (thatst he code in your glove box) it is identical to the 4-speed version (4LM60) only it has an overdrive gear ratio of 0.73:1 with a first gear ratio being 4.02:1. The trany is said to be knows as expensive to repair and is rebuted to need repair often in hard use. In service manuals it shows as the 85mm 5-speed. Oddly, the GM manuals show that this trany has a 310LB-FT imput torque rating. As a comparison, the SM456 only is rated at 290LB-FT imput torque ration. (Personaly I believe these #'s to be bogas because the SM456 is BOMB PROOF.
Ok, now about the trany thats in your truck.
It is a NV3500. Its found in all 1/2tons and some light 3/4tons from 1995 and up to present. It is also found in all S-series trucks from 94 and up. This trany is made by New Venture but is not at all similar to the NV4500. Its basically a new version of the Getrag built by NVG. It shares the same looks and most of the internals as the Getrag and also has the same gear ratio's in ever gear. It is also expensive to fix and has an all aluminum case. It is said to have minor improvments over the Getrag but only has a 280lB-FT imput torque rating compared to the Getrags 310lB-FT
That should help you out a little.
93 GMC Yukon
Chevy SuperStock 4x4 Truck Puller
Great Lakes Truck & Tractor Pulling Association