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MG MGA - Towing MGA with T-9 Transmission

I have seen several comments in the archives on towing an MGA with standard transmission both favorable and unfavorable.

Does anyone have opinions on tow-bar or dolly towing a car with a T-9 Sierra transmission. (Possibly long distances like 2,500mi to Reno, NV).

Jim
Jim Ferguson

I cant see why towing an MGA with a T9 Sierra box would cause a problem any more than driving the car the same distance would. (same applies to the standard gearbox)
The rotation of the rear wheels when towing the car would, via the driveshaft, rotate the output shaft of the gearbox in neutral. But there would be no real stress put on it or its bearings as it would be more or less free wheeling. The only problem I could see is if there was a lack of oil in the box.

If you were really worried about it you could always disconnect the drive shaft at the diff and secure it safely out of the way of rotating diff flange.

The only problem I have heard of is when towing an automatic gearbox so this doesnt really apply to the MGA.

Anyone else know any different to this?

Colyn
Colyn Firth

While being pulled in neutral the only parts inside the transmission not spinning will be the input shaft and bearing. the spinning components will move oil as needed. My only concern is the needle bearings between the input shaft and the mainshaft. Normally there is movement here only while clutch pedal is depressed. For a short pull this would not concern me. For your long pull I would disconnect the rear flange of the driveshaft.
I have seen 3 different towing situations that have caused damage. One was a 1990 Lexus LS 400. It had an automatic transmission and would be expected to fail being towed this way. It was towed from Washington state. As it was being towed through Denver the transmission finally seized, it got so hot that the wire harness on the outside of the trans literally melted. Another was a Suzuki Sidekick pulled behind a motorhome. In this case the owner left it in 1st gear and towed it up to highway speeds. This caused the engine to spin so fast that it threw all 4 rods through the side of the block within minutes. The engine was destroyed but the transmission was ok. The last case I will discuss was a Datsun 240z. It was towed in neutral. After a long time the trans failed locking the input and mainshafts together. The car owner discovered the problem when the engine seized. This instance destroyed both the engine and the transmission.
Case 1 does not apply.
Case 2 only applies if the car is carelessly left in gear.
Case 3 is why I would disconnect the drive shaft.
Reaching under the battery cover there is enough room to do this.
R J Brown

If you remove the drive shaft at the rear universal joint be sure to tie it with strong wire to some chassis part as I do not know how the spline works on a T9 and driveshaft. You would not want to see the spline disengage and the drive shaft land on the road or through the windscreen of a car behind you.
The spline may have locking system to prevent it coming apart. I don't know.

Mick
M F Anderson

If you remove the drive shaft completely you will probably lose all the oil from rear of the gearbox.
So it would be better to leave the front of the driveshaft installed in the gearbox and just disconnect at the rear.(4 nuts and bolts)
Then support the disconnected driveshaft so it doesnt drag on the road or fall off.

Colyn
Colyn Firth

There are many reports of MGs with original type gearboxes being flat towed all over the place with no problem. I towed one over 100 miles on a couple of occasions with no problem. This is because there is a rudimentary oil pump on the output shaft they works whenever the propshaft turns in the forward direction. The description of how that works is on my web site. The oil being pumped lubricates the mainshaft bushings for 2nd and 3rd gears as well as the needle roller spigot bearing at front end of the mainshaft. The center ball bearing dips in the oil while the rear bearing or bushing is fed oil via a small trough along the right inside wall. This is assuming there is oil in the gearbox.

I did once own an Austin America with 1275 engine and 4-speed automatic gearbox. That also has an oil pump on the output shaft which is good for generating hydraulic pressure to operate the 2nd gear hydraulic servo to enable push start (at about 20 mph). I also flat towed one of those 150 miles with no problem.

For the Ford T9 gearbox, I dunno, as I have never had reason to ask or look, because I never owned one. My best guess is that it will also have some internal provision for oiling while being towed.
Barney Gaylord

If I was towing 2,500 miles I would disconnect the drive shaft at the rear universal joint just to save wasted energy in the towing. Why turn over the shaft and most of the gearbox for no reason.


Mick
M F Anderson

Not much friction in there while towing. The only thing turning is the mainshaft running in three bearings, and idling in two bushings for the stationary 2nd and 3rd gears. Those few bearings and bushings would be the concern (if you can't believe that there is an oil pump supplying oil to these parts while being towed).

Oh, the speedometer drive also runs. For long distance towing you might want to disconnect the cable from back of speedometer rather than disconnecting the drive shaft.
Barney Gaylord

As Barney says, there are no gears turning.

The first motion shaft is stationary as it is splined into the clutch, which is on a stationary engine.

The laygear is meshed with the first motion shaft and 2nd & 3rd gears are meshed with the laygear, so nothing turning there, either.
Dave O'Neill 2

There are definitely vehicles out there that cannot be flat towed without doing damage to the transmission, and in some cases the transfer case of 4wd vehicles. Since nobody here seems to know whether or not this is true of your T-9, it would seem to be a good idea to seek the answer elsewhere.
Del Rawlins

Jim, I found this diagram of the Type 9 and it doesn't appear to have anything attached to the output shaft that would sling lubricant up onto the shaft and the roller bearings between the output shaft and the intermediate shaft once the 5th gear synchro is in neutral. For long distance I would be concerned about wear on those bearings so removing the drive shaft would be a good idea. You might check with some professional tow services, they usually have manuals that show the correct towing instructions for all cars and the directions for a Mekur would be the same as it used the same transmission.


Bill Young

I can't tell from that diagram, but if there is an oil pump it would be located on the output shaft just forward of the speedometer drive gear (in the area that is not cut away in the diagram).
Barney Gaylord

I just bought a Haznes manual for the Sierra so that I will have the gen on this gearbox (That is if we ever manage to get hold of Peter Gamble so that I can get the information of why mine doesn't fit together properly)

I'll post some details from the manual online. But for the £1 plus $3 shipping I guess it's within anyone's budget to buy a copy. It's still copyright material so I can't scan and post it.
dominic clancy

This thread was discussed between 06/10/2010 and 11/10/2010

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