Afterthoughts
First, I’m not personally familiar with the term “flat tow.” I’m assuming that means towing it with a tow bar and all four wheels of the truck are on the ground, as opposed to on a trailer or two wheels on a tow dolly.
Disclaimer: These are generalizations, and you’d actually have to double check this Vehicle by Vehicle, but this is fairly universal. Understand a little bit about lubrication and cooling in the different kinds of transmissions.
Automatic transmissions are driven by hydraulic power. There is no direct gear to gear connection between the engine and the output shaft of the transmission. The engine spins the torque converter and creates hydraulic pressure with the automatic transmission fluid which circulates everywhere and anywhere in that transmission and pushes it around via wet clutches.. Pushing the ATF everywhere is also how the transmission is lubricated, and finally, in an automatic transmission, the fluid is also flowing through a cooler up by the radiator fan to keep the whole gizmo from overheating. If the pump dies, the transmission dies. If the engine stops pushing the torque converter, the transmission dies.
There is no fluid pump in a manual transmission. There are also very few fine parts, no friction surfaces, other than the gears connecting. It’s a mechanical monster without hydraulics or electronics or whatever. The gears sit in the case, which is basically just a box, and it’s usually about half full with the appropriate gear oil or fluid. All the parts are lubricated by the gears splashing through that pool and throwing the fluid everywhere and coding everything. There is also no external cooling mechanism. It doesn’t generate near the amount of heat that an automatic transmission generates because there are no friction surfaces/clutches pushing everything, so the heat loss through the case is adequate to keep it from overheating.
If you tow a vehicle with an automatic transmission, even if you put it in neutral, there are parts in that transmission that are spinning and doing whatever they do. But there is no forced lubrication, and there is no cooling. So if you tow it very far, you run the risk of overheating the components, and burning them up, or perhaps doing damage to a few gears that are in there because they are not lubricated.
In the manual transmission, whether everything is rotated from the engine shaft, or you’re towing it down the road and everything is rotating from the driveshaft from the back wheels, all the lubrication works the same way, and the heat dissipation works the same way. I think the only way you could suffer damage from Towing is if it ran low on fluid, which of course will kill anything that requires lubrication.
The early Ranger standard transmissions were just gears in a case half filled with oil. I personally don’t see how they could get damaged pulling them down the road.
Having said all of that, I’ve towed a bunch of vehicles with tow bars over the years. I made a universal tow bar out of some angle iron and threaded rod in the early 80s, and I still have it. I have towed cars with automatic transmissions, fortunately without damage, but I didn’t know any better when I was doing it. I wouldn’t do it again without dropping the driveshaft.
The other thing about Towing with a tow bar is making sure the front end of the tow vehicle is aligned properly. I always forget which is castor and which is camber, etc., but if they are not set right, the front wheels can jump from left to right as you go down the road. If you’re going to tow it very regularly, you can go to an alignment shop and actually have them intentionally set the wheels back (I think) so they will drag like a trailer. But that can give you understeer (I think) when you’re driving that towed vehicle. I might be wrong on those specific details, but you get the idea.
I also always tie my steering wheel off to the frame of the seat or something like that so it can only move a certain distance. If something goes wrong, it’s much more likely it will track behind the Towing vehicle instead of cutting off to the left or the right suddenly. If it suddenly cuts to the left or right because something goes wrong with the suspension or the tow bar, remember it’s tied to the back end of your vehicle with a chain, and it’s going to pull that left or right.
I used to tow a 60’s vintage F600 dump truck with a Chevy C20 regularly when I first built it in the 80s. The other thing I learned over the years: no matter how well it pulls and no matter how steady it is, I wouldn’t go more than 55 or 60 miles an hour. It’s an infinitely more complex, dynamic situation than driving a single vehicle, and things can go south in a heartbeat.
I hope it helps.
