Question..... towing damage = ruined drivetrain?

[300SDog]

I'd greatly appreciate the opinion of sharpies on this board regarding towing damage.....

My plan is to put an old chassis#110 finbody on the road - souped up with my 85mph 240 engine from my dailly driver '79 rustbucket. Have been told the newer engine will drop right into the older car.

The straight body, standard shift '60s car am now looking at was towed from Texas to New England without disconnecting rear axles or driveshaft several years ago...... Owner tells me transmission damage resulted, but was not specific.

The car isnt running. Am planning to jack up both rear wheels and check for play in differential, axles, etc.

What can i expect to find wrong with drivetrain of standard shift sedan that was towed with rear wheels spinning more than 2,000 miles?

[P.E.Haiges]

Diesel Dog,

How would towing be much different than driving a manual shift car except that it is done in neutral? I doubt if any damage would be done to any of the driveline parts including the transmission.

An automatic transmission is different. The front oil pump is not turning when being towed so some parts are not properly lubricated or things that should pressurized by the oil are not, so an auto transmission can be damaged by towing.

It is usually recommended to disconnect the driveshaft when towing an automatic transmission car with the drive wheels down. I have never seen it recommended to disconnect drive shaft on a manual shift car when towing. Even with the driveshaft disconnected, the axles and differential gears are moving when being towed, about the same as when driving the car and no damage would occur.

P E H

[P.E.Haiges]

Diesel Dog,

I put a 220D engine in a 200D one time, but took it back out because I needed the engine in another 220D.

If I remember correctly, I had to use a 190D bell housing, something on the 200D bell housing would not fit.

There is no clearance for the 220D oil filter in the 190D body, so I had to modify the 220D oil filter housing. I never finished the installation, so I can't tell you of the results.

P E H

[Brad123D]

Diesel dog,
Sounds like a cool engine swap you have planned ! I hope you keep us informed of your progress. IMO, engine swappers with a good plan rank toward the pinnacle of mechanicdom !
I rebuild my own auto trannies (GM only, so far) and can mostly 2nd PEH's opinion. An Automatic will primarily have some of it's bushings ruined if towed...similar to running an engine without oil pressure. It seems like a standard tranny should still get enough lube, but it does seem possible to me, that on a long tow, the output shaft bearings or seal on the tranny may have been damaged or maybe failed simply from old age. Let us know what you find out.

[300SDog]

Haiges, these are not straight cut gears in the manual tranny - torque working in wrong direction raises hell with slant cut gears and synchromesh. This is what I've been told elsewhere.

Am wondering if same thing applies to differential and axles. If so, then will not pursue this particular car especially as the tranny is junk.

TY4 the caution on oil filter housing adaptation...... also the heads up on using the 190 bellhousing A/K/A 190 tranny.

Btw, recipient car is rust free '62 190..... donor dailly driver is '79 w123 240D with helaciously fast low mileage engine.

Why the finbody?? Personal preference guides me to an era when MB owned the international taxi cab industry back in the '60s..... easily the simplest and most functional cars MB ever made - zero electronics and no tricky vacuum system with millions of vacuum lines.

Thanks for the replies, will keep the board informed as progress is made on this special project.

[johngray]

Many people don't realize that in a manual transmission with the engine off and the car rolling the gears in the transmission are not even turning! So there are no countershaft gears turning to splash lubricant into the upper part of the trans where the mainshaft is turning inside the stationary mainshaft gears. Oil starvation could indeed result on long "four down" tows. Ask the RV crowd, they know all about this. I don't think shorter tows of 40-50 miles or maybe even somewhat longer at moderate speed would result in damage since there is sufficient amount of lubricant already in or clinging to the parts, but long tows could result in damage to bearings especially. The differential would be OK though.

[P.E.Haiges]

Diesel Dog,

But every time you take your foot off the accelerator, the torque is reversed with much more force on the gears than the small friction drag causes when towing.

I suppose it is possible as Brad says that the rear bearing could be damaged by lack of lubrication when towing, but I never heard of it happening. I towed my 190D about 800 miles with no noticeable damage.

If you need a 190D transmission I have one for sale.

P E H

It may be coincidence that my manual trans needed
to rebuilt after I made several trips from Mammoth
Lakes to Bishop Ca. There is at least a 2000 ft.
change in altitude and I left it in neutral going down
over 40 miles figuring the engine was happier.
This was in a Ford and it was a used car, but
the shop that rebuilt it said not to coast in neutral
and explained what johngray just did about the
gears not turning, and hence lack of splash lube
to the bearings. The bearings were ruined.

[84300DT]

donor dailly driver is '79 w123 240D with" helaciously fast"


i can attest to that part, dog, whew..
it tried to keep up with you after the gtg, no dice.

good luck with your project.