9

My daughter had a friend tow her 1996 chevy (automatic transmission) SLOWLY, without engine running and while in "N", probably for 7 or 8 miles. Do you think she has damaged the transmission? The car overheated due to a leaking heater hose.

  • Towing any vehicle with an automatic transmission not in neutral,will mess it up. So the answer is no! Towing a car in neutral is how you tow it. – David Ward Mar 7 '17 at 12:19
12

Most owner's manuals state that the vehicle should not be towed with the drive wheels on the ground for longer than x miles or faster than y MPH. The reason for this is that Neutral only disengages the engine from the transmission, but not the transmission from the wheels. As the drive wheels turn, the transmission turns. This can heat up the transmission, which is not being cooled because the engine is not on or engaged, so the transmission fluid pump might not be cooling the transmission. The transmission is not getting proper lubrication for similar reasons.


For example, a 2004 Chrysler Sebring owner's manual states:

Flat bed towing is the preferred towing method. If a flat bed towing vehicle is not available, a wheel lift towing vehicle may be used.

Rear towing is not recommended with the front wheels on the ground, as transaxle damage can result. If rear towing is the only alternative, a front end dolly must be used.

It also states that, if you must tow it with the drive wheels on the ground:

Automatic Transaxle - Your vehicle may be towed under the following conditions: The gear selector must be in NEUTRAL, the distance to be towed must not exceed 15 miles (25 km), and the towing speed must not exceed 25 mph (40 km/h). If the transaxle is not operative, or if the vehicle is to be towed more than 15 miles (25 km), the vehicle must be towed with the front wheels off the ground.

Manual Transaxle - If your vehicle is equipped with a manual transaxle, it may be towed at any legal highway speed, for any distance, if the transaxle is in neutral.

So, if you towed it for only 7 or 8 miles at a speed lower than 25 MPH, you are probably safe. You certainly want to keep such towing to a minimum.

  • Do you think the same restrictions apply to CVTs and DCTs? – rana Nov 3 '15 at 19:11
  • @rana, I would imagine so and for exactly the same reasons. I looked up the owner's manuals for a 2015 Chevy Spark (with Continuously Variable Transmission), which recommended you never tow it flat. A 2014 Ford C-Max (with Dual-Clutch Transmission) owner's manual allowed flat towing at 35 mph for up to 50 miles. In any case, an automatic transmission would still be coupled with the wheels, even in Neutral. – Poisson Fish Nov 3 '15 at 20:24
  • 2
    +1 I totally agree with this answer. I do think that the key point will be that the transmission will not be getting lubricated. Since the torque converter will not be running, I don't think there will be much heat build up unless some of the clutches or brake bands are semi engaged. – HandyHowie Nov 3 '15 at 20:34
  • As @HandyHowie states. In most automatic transmissions, the pump is run by the torque converter, and it is connected to the engine (via the flexplate). If the engine isn't running, the pump isn't running ... no two ways about it. This causes a lack of lubricant, which causes the rear of the transmission (parts closest to the output) to get a lot of abuse. – Pᴀᴜʟsᴛᴇʀ2 Nov 3 '15 at 23:26
  • Fair point to add, it's -35f here; I bet I could push those limits a little bit without it overheating, but lubrication is still a problem. – Steve Byrne Feb 8 at 14:41
0

I arrived at a job yesterday to colect a car,which turned out to be auto.engine was running but overheating on load,I left motor running with transmission in neutral and towed it at 60mph for nearly 200 miles stopping frequently to check temps etc and had no problems whatsoever.recovered car was a petrol peugeot 206,other cars may give problems but this one was fine with it

0

Considering that hybrid cars are becoming more and more common, and considering that hybrids are usually thought to have an automatic transmission, I'm going to provide a hybrid-specific answer.

On Toyota hybrids, there is a maximum speed limit that you must absolutely observe when towing the car in neutral and without the engine running. The reason for this is that the car contains a planetary gearset with three shafts: one going to the wheels and motor-generator 2 (MG2), another going to the internal combustion engine (ICE) and the third going to MG1.

Now, if the ICE is stopped, and the car is moving forwards, the MG1 will spin quickly in the reverse direction. Without the ICE running, it is actually possible for the MG1 to overrev.

On my car (a 2016 Toyota RAV4 hybrid), I believe the limit where MG1 will overrev is 80 km/h. This information is based on observing the fact that the electric vehicle (EV) light is never on at speeds over 80 km/h, but at speeds below 80 km/h, the EV light can be occasionally on.

I now don't remember what the manual says about maximum towing speed, but I would try to be safe and consider the limit to be even lower, 60 km/h (actually in Finland it's illegal to tow a car with a rope at speeds above 60 km/h). Observing this lower limit eliminates the possibility for MG1 to overrev.

Of course, as this car is electrically controlled, without electricity you cannot change the transmission to the N position. So, you may need a jump-start to be able to use the N position.

Not the answer you're looking for? Browse other questions tagged or ask your own question.