Automatic Gearbox Details

When the motor is running it runs the torque converter that turns the oil pump in the transmission, that's lubes it. When you towed it the wheels run the transmission but it don't run the lube pump. With out lube the transmission is toast.

Put the gearbox in neutral. I've towed auto cars like this, no probs.

Don't try that on Ford,GM,CHRYSLER

outch - mine just happens to be a chev (GM)..

Does the auto box really require a pump to be lubricated? It's filled with 5 liters of ATF anyway. Or is the torque converter driven pump only there to supply the automatic shifting mechanism/brain with blood ?

All the oil is in the bottom of the case.

...so with no engine-driven pumping action all the rotating metal faces in the torque converter have nothing to wet their whistle with. Sounds like bad news - unless there's Extended Warranty on it.

Vehicle manufacturers put a warning in their manuals against doing this. Of course, it's in the small print, so that there is an increase in the level of business of changing faulty torque converters for the unwary...

On this side of pond drives know not to pull a vehicle newer than a 1950 with a automatic transmission!

There are drivers newer than 1990 these days...

I don't know if you have TOW TRUCKS? But we do.

"Boy racers" - most of these were built around 1990, it seems, though none is likely to touch a vehicle with an automatic transmission, being a much too leisurely way to travel...

BOY RACERS ????

Tow trucks? We have recovery vehicles that pick the cars up!

...which shows the manufacturer's recommended way of recovering a failed automatic. So there. With knobs on.

That ok for little cars.

Here's one a little bit bigger. The bus is an automatic...

Where are the wheels?

They fell off, together with the automatic gearbox and the torque coverter!!!

I don't know what time it is there,but here it time I get my butt back to work.

Later

I have often seen automatics towed with the rear wheels in the air

and the steering locked with a rope to save the trans

Knowledge can be communicated but not Wisdom

Although oil is a contribrotory factor it is not the whole cause and even with oil being pumped - over filled etc. The main cause is the science of the gearbox. 3 componnents in the gearing 1 Sun - 2 Plannet - 3 Outer Ring. - the sun gear is big, compared to the plannets - the outer ring is big compared, to the planets and when in operation the drive either the outer ring or the sun and turn at very low speeds or are even stationary compared to the other gears and therefore realetivly little frictional heat is caused. However when being towed and even in nutral the plannet gears become the driven and reach speeds well in excess of what they are designed for, create a lot of heat - being small gears the eventually burn out. So small distances at very low speed is almost certainly safe - increase the distance increase the risck of damage increase the speed increase the risk of damage.

Your contrrbution makes a lot of technical sense. Since the critical factor is the speed of towing, can I then safely conclude that I can push the car a few yards off the road in case of a breakdown in the middle of a busy road, provided I do so at speeds not greater than 1 KM/H ?

linkshope

I haven't been inside a planetary gearbox yet, but what happens then, when you go downhill at, say, 80 km/h, foot off the throttle, and the car's weight pushes the drivetrain just as in towing. Is the oil supply from the torque converter/pump with the engine idling then enaugh to keep your fast spinning planetary gears from catching fire ?

Further, what is actually engaged when the transmission is in NEUTRAL ?

Here in Australia, NSW, it is illegal to do what's called "slack rope towing " anymore with a rope, chain or cable & both drivers will be fined quite heavily so you have to get a tow-truck or flat-top to take it to the nearest repair shop or to home & nearly all our tow trucks have a front or back wheels lifters fitted, if you are not in one of our motoring oganizations such as N.R.M.A. etc. at best it will cost you a $150/= or so bucks to get your car somewhere, try re-building your auto. transmission for that reatively small cost !!!

Brien.

Beside get killed do it. 20 foot chain 50 mile/hour to better be fast on the brake.

i have an experienced before,customer towed his automatic transmission car for almost 50kilometer,the transmission case was so hot,when we open it we saw all the clutches were burned,we changed it and replaced all the o rings and assemble it,it work again.

If you are talking about tow-truck usage on a >front wheel drive< car then your safe as long as they have the front wheels on the little platform behind the truck. If it's rear wheel drive then they need to have the rear wheels up. If you have all wheel drive then it starts getting expensive (all wheels up). See the connection? Try to keep your drive wheels from turning when the engine isn't running. If you're talking about towing with a chain behind another vehicle, you'd better know what your doing. It's not the best idea to do, but can be fun!

Actually its not just automatic vehicles that shouldn't be towed with the drive wheels turning unless the engine can idle during the process. Manual transmissions have slip yokes too that need lube; also depending on the design of the trans, the counter shaft probably isn't turning which slobbers oil up onto the bearings of the output shaft. Often times when towing medium & heavey duty trucks the driveshafts are removed to prevent damage to trans, esp. when they are piggybacked for transport.

Over the past 30+ years, I have "slack rope" towed (or have been towed) a number of times with manual and automatic transmission equipped autos and have never had the first hint of any transmission problem.

The towed car is always towed in neutral, where the internals may spin but without any significant load (i.e., they neither drive the wheels or the engine). Of course, where possible, we'd have the engine of the towed car running for the power steering and brakes. Often, though, the engine of the towed car would be the problem and not be running. The towed distances would not generally have been more than a couple of miles and the speeds kept at 35 mph or below.

In fact, in my youth, I recall successfully starting the engine of an automatic transmission equipped towed car (or two or three) by pulling or pushing it up to about 25 mph or so.

Some may think these practices to be have been unwise but, we did ever so much more that was ever so much more unwise. We were stupid and did stupid things. For example, playing "bump tag" with friends in other vehicles at speeds of up to 95 or so, driving off the road and onto grassy areas at high speeds to see how many spins we could achieve, driving over/through humps or dips fast enough to get airborne, turning off the ignition while draiving at speed and pumping the accelerator to flood the engine before turning the ignition and producing loud, muffler destroying exhaust explosions, catching passengers unaware and flinging them hazardously forward by executing random, severe "brake checks," participating in "pedal-to-the-metal" distance contests with friends in other cars, doing many of the foregoing while not wearing any seat belts..., etc., etc.

Ah the follies of youth...and may the less fortunate, and there are a good number (Darwin casualties) RIP.

Pull/push starting the vehicle with automatic, I've heard of this before but cannot recall what make. I think it was some Crystlers that used a pump on the tailshaft as part of the feedback for auto shift controll. I know the Hydromatics that GM used mostly implemented a spring returned governor that would bleed pressure off a circuit to control the shift spools. I thought others, not sure which, used a pump to add pressure to the other side of the spool to achieve the same effect.