transmission and towing

[sick620]

A friend and I got into an arguement. I have read on here that you have got to unhook a driveline to tow a vehicle on a car Dolly for a long period of time or you risk frying your tranny. He said that only applys to automatics... is he right? If not what's the science behind the whole fried transmission thing?

[elmerfudpucker]

If it is only 50 miles or less you are ok, anything farther than that I unhook the driveline from the axle. The idea is the tranny is getting worked and I think the oil cooling part only happens while the engines running. If you are towing on a dolly, easy fix is put the drive wheels on the dolly.

[Grey_Matter]

well i was a tow truck driver.....

 

you CAN F up a manual tranny if you tow it without disconnecting the driveline if you tow it over a long distance.

 

rule of thumb: if you have to take it more than 5 miles you need to disconnect the driveline or you will over heat the tranny.

 

 

but the same rule applies for auto trannys. some of them can just be dropped into neutral and towed for a short distance, but if you have to take it more than 3 miles you need to disconnect the driveline.

 

if i had to tow an auto tranny vehicle i would just grab it from the drive axle so i didnt have to disconnect anything.

[datzenmike]

As long as the drive shaft is turning, even in neutral, all gears are spinning and splashing oil around. In neutral there is no engine to turn so very little load on any one gear. I don't see why there would be a problem towing a standard with the driveshaft on. It would be the same as coasting down a mountain in neutral. A long mountain. I'm not saying you can... only that I don't see a problem.

 

Auto are different. They need the motor running to power the oil pump inside. I suppose you could tow an auto with the engine idling.

[wildmaninid]

I have towed several datsuns, one across country, the most recent my 620 up from missoula to north idaho, all were manual trans and I have never had a problem. Auto's I always disconnect the driveline, and try to bungee it up to the frame somewhere so the atf won't spill out the tailshaft while it's on my dolly.........

[blue72]

When I first bought my Z I towed it 25 miles home with the trans in neutral on a car dolley. A year or so later I had the trans apart and everything looked perfect (gears, seals, bearings, etc...).

When the engine is running the input shaft is turning and driving the gears, but when it is being towed with the rear wheels on the ground then it is the output shaft that is being spun instead.

It may very well depend on the design of the manual transmission itself, eg: what is turning and whether any oil is being splashed onto those bits that are turning. Some transmissions might only sling oil when receiving power from through the input shaft for instance, or perhaps the output shaft itself won't have any oil lubricating it if only it is spinning.

[herculesinwyoming]

well there are also all the old retired people that tow a car behind thier motorhome/bus, with all four wheels on the ground and they go all over the country. i see alot of them tow a little car with a manual tranny.

[datsunaholic]

Automatics have to have the driveline disconnected because the only source of fluid pressure is via the input shaft, which turns the pump in the transmission.

 

Manuals have no pump, as everything is splash-lubed. ANY gear that's being turned in a manual is getting lubed as long as there's sufficient oil in it. What towing connected DOES do is put a backward load on the transmission, but that happens whenever you decelerate when driving anyway. So in reality there's no harm done. In Neutral it's not connected to any of the driving gears anyway, so there's nothing to backload.

 

But... what CAN happen is the shifter COULD conceivably fall into gear if you hit a bump or such, which would be a very bad thing. That being said, I've towed trucks 350 miles+ with and without disconnecting the driveshafts, and none of the ones I towed long-distance ever had transmission problems.

[]2eDeYe]

But... what CAN happen is the shifter COULD conceivably fall into gear if you hit a bump or such, which would be a very bad thing.

 

This happened to me many years ago. I learned the hard way, shortly after that, about the difference between an L trans and a Z trans :lol:

[5dimer]

I learned it the hard way in my move to Utah this month. I broke something in my Dodge Darts auto trans. Their is a puddle of fluid under it right now!!!!!!

[ggzilla]

What does NISSAN say about this?

 

* When towing an automatic transmission model, try to restrict towing speed below 30 km/h (20 MPH) and towing distance less than 30 km (20 miles).

* With manual transmission model, try to restrict towing speed below 80km/h (50 MPH) and towing distance less then 80 km (50 miles).

* If the speed or distance must necessarily be greater, remove the propeller shaft beforehand to prevent damage to the transmission

* Release the parking brake and set the gearshift lever in the "Neutral" position before starting to tow the car.

[bonvo]

odds are if the car has to be towed its not running not running means sitting which means that the reg could be out of date i dont know about other states but i know in california it is illegal to have any wheels of an unregistered vehicle on the road even if its the back wheels while being towed on a dolly solution use a car trailer keeps all 4 wheels off the ground so no laws are broken and there is no movment the entire trip so no need to disconnect the driveline