I ran across this thread in a search, I see It's nearly a month old... here's some info...
the 87 1/2 ton diesels have 700r4 (4l60) and the most common gear ratios I've come across are 3.41's
3/4t models have the good o'l th400 most with 4.10 gears and a few options being 3.55, 3.73, 4.10, and some 4.56
the 87 6.2'l get slightly better mileage with the sm465, I converted the other way in my p/u.
some of the th475 trannies have straight cut planetaries that give a lower 1st, 2nd, and reverse gear.
If the 73 DRW was originally automatic, It had a th400 in it.
also the th 400 bolted to the 6.2 diesel will bolt on the SBC's and BBC's. the share the same Chevrolet bell housing.
more on the above mentioned "BOP diesel" bell housing by Jerry....
none of the th400 have uni-case bell housings, some th350, th200, th2004r trannies do.
in 78 gm intro'd a 5.7 and 4.2 ltr. diesel in the form of a "look-a-like" 350 Oldsmobile, the only thing the the 350 gasaholic shares is brackets, and the water pump, all the internals are completely different and unswappable, although the diesel heads will bolt on a gas engine and vice versa. the blocks are clearly marked as 260 D, 350 D and 350 DX which was the upgraded engine for the 5.7 diesel. they in no way shape or form similar to the gm 6.2 and 6.5 diesels except for one part... the injection pump has the same internals up till 94 when they when electronic.
shift kits are often associated/misinterpreted with performance.. not all shift kits are harmful to drive train components and the tranny itself.
B&M makes performance kits and generally do some serious hammering when they shift.
Trans-go shift kits are from mild to wild and are beneficial the the life of the drive train and tranny depending on which kit ya stuff in and how it's adjusted.
the diesel converters are lower stall and have heavy duty parts
the th400 and some Allison's share converters though the Allison version is a little to low stalled for the 6.2 they tend to not want to back up when parked on a steep hill because of the low stall. the gm 6.2l and 6.5l work the best with a 1500-2200 stall speed as the torque of the factory 6.5td is up to 440 lb-ft at 1800 rpm and 215 horsepower @ 3200 rpm. latest versions are factory 300 hp. the 6.2L torques out at 257 lb-ft @ 2000 rpm and 143 hp @ 3600 rpm. up untill they get a ATS or a Banks sidewinder turbo bolted on em.
despite popular belief and what the diesel guru's preach, the gm 6.2L and 6.5L need a higher stall than than the Cummings and international diesels.
one last thing.... they'll do 95 accidentally.
