Towing M5 with dolly

[DonaldSmith]

Thinking contingency plans for our jaunt to the National DeSoto Club Convention this summer, my son-in-law has a truck capable of towing my 2-ton beast, with a dolly.  It wouldn't be much fun, 55mph (88 kmh) or less.  But if I can't get the Big Brown Car running, the dolly is an option.  

 

Question:  Would we have to remove the driveshaft, or will the M5 transmission tolerate the revolutions?   (In ancient times, my brother trashed a Hydra-Matic by trying to push-start a  Cadillac.  U-Haul recommends the dolly only for front-wheel-drive cars, to avoid such a possibility.

[Tired iron]

if youre renting a dolly, maybe just rent a full trailer instead and get the whole car up off its wheels.

[Los_Control]

I can not offer a opinion on the drive shaft.

 

The tow dolly is a good alternative to a trailer. U-Haul will suggest 55mph to be on the safe side for liability.

Here in Texas I often see people use tow dolly. Is common to see some dealer coming from a car auction. They will have a flatbed with one car on it, then using a tow dolly pulling a 2nd car, then a special tow dolly connected to the 2nd car pulling a 3rd car ...... pulling double trailers I guess is the term.

They are cruising down the freeway 75 mph with no problems. ...... U-Haul takes good care of their equipment usually ..... you should be fine.

 

The only thing I know about automatic transmissions, you need the engine running to turn the front pump on the transmission to circulate the oil.

If only the drive shaft is rotating, not the pump .... then the internals are rotating without proper lubrication.

[DonaldSmith]

I checked the Shop manual.  I see that the oil pump drive gear is on the main shaft, right next to the speedometer gear.   Theoretically, the transmission should be OK if the car is towed with the rear wheels on the road.  But what do I know.  

 

I checked the standard U-Haul towing trailers.  My wheelbase,  11'-7-1/2", won't sit happy  on a12'-4" bed.  And the car would hang over about 3 feet, front and back.   We would have to find a longer trailer.   

 

This gives me something to think about while I'm waiting for the carb rebuild kit.  (Per the "Won't rev" thread)

[Los_Control]

U-haul also have some very specific qualifications your truck has to meet in order to rent you a trailer.

 

A friend of mine had a car trailer & pulled it with his 3/4 ton truck all the time. He needed to rent a longer trailer to pull 1 vehicle.

The only way they would rent him the trailer, he had to also rent a 1 ton box van to pull it with. ..... Again for liability reasons.

 

My employer went down to rent a bob cat one time. His truck & trailer was fine, but his tie down straps were 3" wide ..... they would not load it unless he rented the 4" straps to tie it down with.

Car dolly they do not have as strict of requirements.

[desoto1939]

DON:  Question, is there anything in your transmission that needs to have the car running with the engine on at all times? So lets say that you needed to push the car to get it off the road onto the side of the road and then engine will not start, will the trans lock up the driveshaft.  I know on my 39 Desoto I put it into neutral and then push the car.

 

I feel that you can safely take the driveshaft off the car entirely at both ends. But first put a red stripe o each pinion end and on the appropriate end on the transa nd the differential so that when you go to put the driveshaft back on you will be putting it back int the same points prior to taking it off the car. This is to insure that you willnot have any vibrations issues.  Also take along a good floor jack so you can get under the car to replace and install the DS and also when you get ready to come home.

 

I drove my 39 Desoto to last years convention and traveled over 550 miles averaging between 50-53 mph

 

Hope you have a great trip.

 

Rich Hartung

[greg g]

I remember putting a 74 or so Coupe de Ville on a u haul trailer, they have a 130 inch wheelbase. It was close, but it fit.  Is the DeSoto longer?

[Tom Skinner]

Back in the Day the 1970's I needed my 1948 Chrysler with the Fluid Drive Towed. The older Tow driver (Probably in his 60's) tied the Steering Wheel and lifted the back of my Chrysler's wheels to tow it in backwards.

When asked why he did that his reply was: "You can monk up the rear end and or the transmission otherwise. If not I can call a Truck to piggyback it in so as not to mess it up"

I personally would never Dolly it with the M5 with the front wheels up on a Dolly. Undoing the Drive Shaft would work, but be sure as to keep the speed of the piggy back dolly below 55 -60mph so as not to burn up gears in the rear end, plus mark front and back positions as indicated above.

I do not know for a fact that what I am saying is correct, but, and I repeat but, those old timers knew what they were talking about. I would not take a U-Haul employees word for anything. The one that hooked up my Truck a year ago with a trailer on it never hooked up the brake lights on it, and I trailered my Daughters car clear across the US with no brake lights on the trailer before realizing it. Hell he was only young enough to be my grandson. The younger people don't know squat about our old busses. They just looking to get you payed up and out of their lot. They wouldn't know about a M5 transmission if you hit them over the head with it. Ignorance is really Bliss. But hey you'll pay the price for their ignorance, not them.

[Tom Skinner]

I also carry a rope in my trunk at all times incase my 1948 Chrysler ever needs towing in. It is to tie off the steering wheel with, to toe it in backwards if need be.

Learned lessons from 45 -50 years ago.

[Dodgeb4ya]

Don't forget when towing anytime the driveline is turning it is turning the transmission output shaft.

That in turn is turning the transmission oil pump in the M-5 transmission which with the ignition turned off allows oil pressure to build up.

Causing the direct speed blocker ring and sleeve to attempt to do a direct speed upshift.

Though because the trans is left in nuetral no shifting happens.

I still would pull the drive shaft on a long high speed tow.

[DonaldSmith]

Gentlemen, I bow to your acquired wisdom.  For a long haul, pull the driveshaft (after marking it for proper reconnection).   Don't temp fate. 

When I first got the car, in 2002, I used a dolly, dropped the driveshaft, and towed the car with my son's Jeep SUV.  He let me drive, and I drove slowly and carefully. 

[Young Ed]

Only thing I've ever car dolly'd backwards was a 66 fury that was a ladies daily driver until the early 2000s when one of the rear wheel bearings died and the wheel hit the inside of the 1/4. So that one went backwards for a little different reason. 

[Los_Control]

Thats something I've seen done with a tow dolly, but never done myself.

I just wonder how well they would handle with the heavy end on the ground & light end on the tongue.

 

Did anyone mention to bring a good come along? You do not want to try to push that beast up the ramps.

 

Always good to be perfectly prepared ..... then nothing happens and all for naught.

[keithb7]

I concur, if  the drive line is turning its directly turning the transmission oil pump. The pump makes pressure and flow only when the drive shaft is turning. The transmission valve check ball, its spring, the shift piston, and its return spring are probably all under unneeded stress from pressure while towing with the rear wheels turning. 
 

Sort of a snot-ball guess as its still not all 100% clear to me how it all works at any given moment. I’ve read the original service manual more than a few times. Watched the dealer Tech videos on it. I probably grasp 80% of it all.  Enough maybe, that I sold my ‘53 Chrysler and now own 2 Mopars with manual 3 speed trannies. Lol. 
 

Edited June 20, 2023 by keithb7

[Rodney_Hamon]

I couldn’t find a trailer to put my ‘36 truck on so I had to use a u-haul dolly to get from Chico to Albuquerque. Hauled it behind my F100 back in 1996. Problem was I couldn’t make the turns as the fenders would rub so I had to remove the truck fenders and front supports. If your car is pushing the width I would be concerned about making the tighter turns.