Hey all, I have a question about towing that absolutely nobody I know has been asble to answer. When using a wrecker; I know it's necessary to unhook the drive shaft or it will cause tranny trouble. What will it actually do to the tranny and how will it do it? I'm mostly referencing a standard. When lifting the back, instead of dropping the shaft, on a long haul, wouldn't that be murder on the steering box? Thanks to anybody with some answers. Brian

 

On an auto trans it has to do with the pump that is not being driven by the motor running causing lubrication problems. On some manual transmissions it can sometimes damage the front bearing to the oil level being low due to the angle of the tow and not getting cooled or lubed.

 

I have towed many with on problames.

 

usually when towing on the front wheels you lock the steering or tie it with a fanbelt or rope/cable so the wheels can't turn.

 

I thought I would offer a little more detail for whats already been said. If you tow for a long distance it can(doesn't always) destroy the transmission. The front pump is critical to everything in an automatic transmission because it is what makes fluid pressure and an automatic runs off fluid pressure. If the motor isn't turning obviously theres no fluid pressure. This is the same reason you can't push start an automatic because if the motor isn't turning the input shaft to the torque converter(big hydraulic clutch basically) is not spinning and theres no fluid pressure to the bands and clutches to engage a gear.

Since the drive shaft is still connected it turning the main shaft of the transmission. The main shaft connects to the planetary gear inside the tranny and this shaft also has bearings and bushings and thrust washers all kinds of guts on it. All these guts need lubrication. Also the bands, clutches and shift solenoids all work off fluid pressure so its possible that something like the clutches, for example, could be dragging slightly all the way down the road. A tow can seem to have worked fine but later the transmission may start to make noise and whine then begin to vibrate and eventually die prematurely due to accelerated wear from being spun dry for too long. I hope this wasn't too much info that was not needed.

 

First off I was expecting to read whether it was an 4x4 or 4x4

Manual or auto trans vehicle you were asking about.

It is because of the concerns over these things that I think Ramp Trucks & Fancy wheel dollies were created.

4x2 with Butt in the air steering wheel roped ...No Problem

4x2 with front in the air with A/T.....Problem

4x4 with either end in the air with M/T for a SHORT distance...no Problem

 

Somewhat unrelated but kind of a hoot - I race a car in SCCA, and one day a fellow shows up in the pits next to me at Watkins Glen with a big motor home pulling an Alfa Spider. His plan was to use the Alfa for errands and going into town. Soon he finds out he left the car in third gear after he put it on the towing dolly, (rear wheels on the ground of course), and never noticed the drag. Everybody figured the engine was toast after the 500 mile tow. It smoked like crazy for 10 minutes after he started it, but eventually cleared up and did'nt make any load noises. Probably took a few miles off it's life..

 

Why would that hurt the engine? Unless the oil pump pickup is uncoverd due to the angle of the car, the oil pump should be turning and pressurizing the oil system because of the wheels turning the engine.

 

It sounds like the motor had a mechanical fuel pump. It is still a problem but a different one now. With the engine turning and no ignition fuel is being sucked into the cylinders and not burned so some of it will leak down into the pan. I hope he changed the oil soon after that happened.

 

Possible. But if the needle and seat are in good shape that shouldn't happen. Unless the angle of the car has the float at a position the needle never closes.

 

4x4s with manual hubs can be put in "Free" and towed forever from the rear.

 

Actually I think the main issue was third gear for 500 miles, probably was spinning the engine around 4500 rpm for most of the 500 miles, with a closed throttle, hence high manifold vacuuam. The high vac. likely pulled a lot of oil past the valve guides, and with no ignition, the oil wound up in the cat and muffler causing the smoke clouds after he started it. This was an newer Fuel Injected Alfa, so probably no fuel was flowing with the ignition off. Engine might have gotten a little hot too without much air flow over the rad.