OT towing cars

[Commander_Chaos]

Sorry for such a generic car question but this is my go-to forum for real answers rather than opinions and guesses.

I have an MG Midget that I tow (more often than I'd like) with a tow-bar. On the car forums I frequent I was told by some that when towing any rear-wheel drive the drive shaft MUST be disconnected to avoid damage to the transmission. Others say this only applies to automatics, rather than the manual trans my car has.

Anyone here really know?

[CPeter]

Only applies to automatics. The gears spinning inside a manual will lubricate the bearings. Actually the early automatics had a pump on the driveshaft end and you could push start them if you got going fast enough, That ended in the 1950s.
Peter

[Willy]

It depends a lot on the particular manual transmission, but in most cases it is advisable to err on the side of caution and disconnect the driveshaft.

What happens is that when towing with the driveshaft connected is that the output shaft spins but the countershaft and cluster gears do not. These are the gears that are normally partially submerged in oil and responsible for splashing the lubricant inside the transmission when the engine spins the input shaft.
Without this lubricant flow the output shaft and the bearings at it's front that line up with and mate with the mainshaft run dry.

I'm not familiar with your particular transmission, it may be different and allow lubricant to flow by turning the output shaft, but if I was unsure I would continue to leave the driveshaft disconnected until I verified that lubricant is allowed to splash by turning the output shaft only.

[Willy]

Only applies to automatics. ..........

Wrong!
It is standard procedure for tow trucks to either lift the drive wheels, put them on a dolly, or remove the drive shaft. Most manuals do not provide lubricant to the rest of the transmission unless the input shaft is spinning.
Some do, but it is customary not to assume so proper procedure errs on the side of caution as most do not.

[J Tiers]

The S10 with manual tranny was not supposed to be towed with rear wheels down. No mention of disconnection, but that would work.

OLD manual trannies were always towed with wheels down. Most tow trucks had no dollies with them until the late 60's or early 70's, might have the dates wrong, but probably mot by much.

These days, you can tow almost every car with the rear wheels down again. That's the same as driving them!

[CarlByrns]

Wrong!
It is standard procedure for tow trucks to either lift the drive wheels, put them on a dolly, or remove the drive shaft. Most manuals do not provide lubricant to the rest of the transmission unless the input shaft is spinning.
Some do, but it is customary not to assume so proper procedure errs on the side of caution as most do not.

Having worked for a driveline manufacturer, I can verify this. We used to test for just this scenario along with extended driving in reverse. Hint: gear transmissions do not lubricate in reverse.

[mikegt4]

A Midget/Sprite (had 2 of them) can be towed wheels down, the transmission is splash lubricated like the rear axle. Transmissions that are pump lubricated, the pump generally being rotated by the input shaft from the running engine, are the ones that you can't tow wheels down. That would include all automatic transmissions.

[A.K. Boomer]

Wrong!
It is standard procedure for tow trucks to either lift the drive wheels, put them on a dolly, or remove the drive shaft. Most manuals do not provide lubricant to the rest of the transmission unless the input shaft is spinning.
Some do, but it is customary not to assume so proper procedure errs on the side of caution as most do not.

Good Man Willy --- so many times im about to "chime in" and see that my bro from the north has already got it covered...

You are a good "wrench" dude...

Might add - so many times this simple information can be found in your owners manual --- set by the people who know the engineering layout of things that Willy just described...

[J Tiers]

heh...... I bet you can tow a ton of new vehicles with the rear wheels down..... They are front wheel drive, and the rears are just along for the ride!

You could for sure do that with the old SAAB 95 and 96.

[Tim Clarke]

The old rule of thumb from my boss at the tow company back in the 70's was: " there's enough residual oil in a manual trans to go across town, but if you're going on the freeway, or farther than 15-20 miles, pull the driveline or use the dolly.

Willy absolutely has it right. Main drive gear turns the countergear, which meshes with gears for the different speeds. all these turn with the engine when the clutch is engaged The output shaft does not turn until a dog clutch connects a reduction gear with the mainshaft, or, couples the main drive gear with the shaft.. In neutral, you can turn the output, and inside the trans, the only thing moving is the main shaft, and the shift collars/synchro assys. Where the lubrication becomes an issue is often the needle rollers hidden inside the main drive gear, where the spigot on the mainshaft rides.

[SVS]

I see a lot of Jeep products flat towed behind motor homes. Transfer case in neutral must be good enough?

[Noitoen]

I thought that on manual transmissions, with the exception of the input shaft itself, all the gears were engaged separated only the synchronizers are always rotating and so, the oil is always moving. Like SVS mentioned, I've seen many German and French motor homes tow small vehicles with an "A" frame with all 4 wheels on the ground.

[epicfail48]

I see a lot of Jeep products flat towed behind motor homes. Transfer case in neutral must be good enough?

You can flat-tow a jeep, but theres a procedure required to keep the engine from grenading itself:
https://jalopnik.com/best-of-2021-je...ner-1846493328

[SVS]

Less a “procedure” than a “cautionary tale”.

Ouch!

[oxford]

I see a lot of Jeep products flat towed behind motor homes. Transfer case in neutral must be good enough?

You could flat tow the old Saturn cars, it was a selling point and a lot of RV people bought them for that reason.