Blackwater
Engineering Geinus
So, a few things -
That is where my transmission is from. The 5th gear nut is on ALL NV4500s, 2wd, 4wd, chevy, dodge.... The factory NV4500 nut is just a fine thread nut - no locks. The locking nuts are aftermarket and there are a few varieties out there.
The main difference is the Dodge trucks typically have the problem with 5th gear backing off. GM generally doesn't have that issue, and there were much fewer GM NV4500 trucks. There are many locking methods for the Dodge 5th gear issue that don't exist for the GM versions - including splined nut retainers and various aftermarket locking shafts. GM only has the option to use the locking nut, and there are no aftermarket locking shafts or splined retainers available.
The difference between the MT8 (92-94) and MW3 (95+) GM NV4500 is the external VS internal slave cylinder, bottleneck vs bolt on shifter, and gear ratios. Both have the same locking nut and possible 5th gear problems. Of note, 95 is an oddball year, higher ratio gearing with external slave cylinder and bolt on top cover... 95 is just a weird year overall.
Now, a large difference with GM vs Dodge is the placement of the 5th gear nut. GM uses two sets of press splines on the back, one for the 5th gear and a second one for a harmonic damper, then the nut is installed. The harmonic damper was used early on, mostly in 6.5L applications but it's indicated in the GM EPC that they were also installed on 5.7L and 7.4L trucks. Later on the dampers weren't used and there was a steel sleeve installed between the 5th gear and the nut, over the splines. Dodge did not have a damper or spacer.
In my application, when 5th gear backed off, it was close enough to the transfercase input shaft that it presses into it, and takes out the input of it. On a Dodge, without the spacer or damper, the gear can move back and simply free spin on the shaft, without hurting the transfercase.
I completely agree with you except the differences on the MT8 Vs MW3. I went with the MW3 because it was fully syncroed and the gear ratios where not as low in the 1-3 gears. 1st and reverse in the first year of the MT8 was 6.34:1, then changed to 5.61:1 in both. first and reverse was not syncroed till the MW3. In 1997 onward the reverse went to 5.04.