See I figured that when trying to carry over my 4WD transmission, it might fit in a legit 4WD platform instead of 2WD, so why not shift the goal to a 4x4 platform? Have that 4WD for winter/offroad plus a heavier base for occasional towing. What ratio are those 77-78 W100 axles usually geared to? They came with anything from the slant 6 to the 360, and the 318 would be right in that ballpark, so the axle would imaginably be geared for that, but I'm still curious.
My main dilemma would be making sure I'm in place for a lockup converter. Doing my research, there are the a518(46rh/46re) and a618(47rh/47re) transmissions. The 618s are the heavier-duty lockup-style transmissions, but since they're designed around the V10s and cummins diesels they won't bolt to the standard gasser blocks. The 46RH variant of the 518 went until about '95, and then afterwards the 46RE had its run. Now, here's where the other part of my research comes in:
From that Hemmings article:
"The 46RH transmissions that were used from 1990-'95 have a three-pin electrical connector on the driver's side of the transmission which controls two solenoids, the overdrive solenoid and the torque converter clutch solenoid. These two units are mounted inside the valve body on one common bracket. The 1996 and up model 46RE units have an 8-pin connector instead of the 3-pin, and
are less desirable for converting into a non-computerized vehicle. You can locate the A-518/46RH transmissions in these donor vehicles:
- 1990-'95 Dodge van with a 318 or 360 engine
- 1992-'95 Dakota with a 318 engine
- 1990-'91 Ramcharger with a 318 or 360 engine
- 1990-'95 Dodge pickup two-wheel drive (1/2- through 1-ton) with a 318 or 360 "
Idk if their lockup list is comprehensive so no clue exactly if my trans falls in there. Again, mine is a 4WD from a 91 Dakota, so safe to assume it's the 46RH variant, just not definitive if it's lockup. Their article makes it sound like there are no ECU-controlled components in the trans, only the 3-wire connector for the OD and converter lockup, however that ramcharger post suggests there's more to it:
"For the earlier TBI motors you can still easily swap in the lockup trans AND have it function. In my case I grabbed a trans from a 93 W250 5.9, swapped the converter to a lockup from an A727 5.9, grabbed the trans harness cable from a 91 318 truck, and everything works perfect.
The wiring in the main harness is there for the lockup, ECU had a code from day 1 for no lockup
solenoid, programming was there just no circuit to energize. The harness that goes between the main harness and the trans (over by the dipstick) was missing the wiring to the lockup, but the 318's had it, everything else is the same. Installed the harness and that was it."
Correct me if I'm wrong, but doesn't it sound like the lockup solenoid is controlled by an ECU circuit? Because if so, then I'd either need to try and setup a switch or circuit to manually engage the lockup (would prefer not having to remember to disengage the circuit at every stop) or be slave to the stock ECU. I'd like to not be slave to the conservative tune the ECU is programmed with, and no telling how it'll behave with twin turbos and ported heads, so I may prefer something aftermarket (some kind of piggyback setup?).
