Push-starting an Automatic Drive

[Commander51]

My 51 Commander has a DG200 transmission. I've read several places that it is possible to push start the car with this tranny. Has anyone put this to the test?? If successful, how about some instructions? I assume you start in Neutral, then shift to Drive, but there's this old saying about "ass-u-me"

[Roscomacaw]

Yes, since it has a rear pump (alot of newer cars don't), it CAN be push started. Start out in neutral, turn the key on, have the car pushed to 15 or 20MPH and while at that speed - select Low or Drive. It should start.

Miscreant at large.

[Peter in London]

That reminds me...... (warning of old story coming!)

We brought out '55 Champion automatic sedan back to the UK in 1957. We lived at the top of a hill outside Oxford. One day for some reason the battery was flat. We decided to start it coasting down the hill - quite long, straight and steep. I towed the car with our little Austin Mini (ordered withing hours of them being unveiled at Morris Garages, from whence the name MG, in Oxford) to the top of the hill, my father in the Stude - and down we went. At the bottom, on the totally level Oxford Southern by-pass, we came to a standstill and my father, exasperated, admitted that he'd forgotten to turn on the ignition! (He'd been our Atomic Energy Attache in DC.) So then I had to tow the Stude with the Mini on the level, which was quite a spectacle and quite an effort (for the Mini). The fastest we could manage was 30mph and at that speed, just, the engine started turning and the Stude started.

So it can be done!

Peter.

[Sonny]

Great story Peter! Tooo funny! Just an added note, I've done it a couple of times, yes it works great. One thing though, the book says to drop it in gear at about 25, I did, (but you're right Peter), neither car started turning 'til about 30 mph.

Sonny

http://RacingStudebakers.com

[wfsiew]

May i know what is the different of front pump and rear pump of Automatic Transmission?
Why the rear pump can push started of the vehicle, and how about the front pump, is this can push started too?

Thank you.

[JDP]

Wow, never heard of dropping it in low or drive while being pushed, seems you'd go into the grill of the pushing car. I always waited until the push car dropped back. BTW, front pump only's can not be push started since the engine turns the front pump, not the driveshaft.

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64 Daytona HT
64 R2 4 speed Challenger
63 R2 4 speed GT Black
63 R2 4 speed GT White
63 GT Hawk
63 Avanti
62 Daytona HT
53 Coupe

[rockne10]

From the 1951 Automatic Drive Owner's Guide:

"PUSH STARTING If it becomes necessary to have your car pushed in order to start the engine, as in the case of a dead battery, turn ignition key on, set automatic choke by depressing and releasing accelerator pedal once, and place lever in N. The car may now be pushed and when you have reached 20 to 30 m.p.h. (32 to 48 km.p.h.), move the lever to D or L position. Do not tow the car to start the engine- your car may overtake the tow car."

These cars also came equipped with a printed sleeve that slipped over the driver's sun visor and provided basic operation instructions for these new automatics.

I have reproduced both the glovebox owner's guide and the visor sleeve if anyone's interested.

With the front and rear pumps in this transmission, it's possible to be running down the road in drive and slam it into reverse. The car will slow down, come to a stop and start going backwards. I wouldn't recommend it for fun but it was designed to enable you to rock back and forth out of snow or mud.

Owner's guide recommends check oil level every 1,000 miles; drain and refill every 15,000 miles.

[wfsiew]

What is the reasons cause the rear pump can push start while the front pump cannot?

[rockne10]

Motion from the rear wheels, through the driveshaft, in to the rear of the transmission must then be carried through the transmission to get the engine to turn over to jumpstart. Without a rear pump the hydraulics in an automatic transmission would not flow through the transmission valve body. Front trans input would not turn, nor would crankshaft, ergo pistons, valves, distributor, et. al. No spark, no jump.

[hank63]

Also, the rear pump was smaller than the front one (at least in Torque Flites). I was told that's why the push-speed had be close to 30 mph before the engine would turn over.
/H

[wfsiew]

Could u explain clearly how does the "output shaft pull the input shaft" in order to get turn to turbine, impeller & engine as well,Pls?

quote:Originally posted by rockne10

Motion from the rear wheels, through the driveshaft, in to the rear of the transmission must then be carried through the transmission to get the engine to turn over to jumpstart. Without a rear pump the hydraulics in an automatic transmission would not flow through the transmission valve body. Front trans input would not turn, nor would crankshaft, ergo pistons, valves, distributor, et. al. No spark, no jump.

[gordr]

[quote]Originally posted by wfsiew

Could u explain clearly how does the "output shaft pull the input shaft" in order to get turn to turbine, impeller & engine as well,Pls?

Well, I'll try.

The automatic drive has a torque convertor, and a 3 speed hydraulically-controlled transmission. Gear changes in the transmission are effected by hydraulic pressure applied to servos (simply devices that turn hydraulic force into mechanical action) which apply the bands or clutch packs. Bands are used to brake some elements of the planetary gearsets, and clutch packs are used to couple other elements together. There is also a direct drive clutch in the torque convertor that locks it up for economical highway cruising.

In any case, no hydraulic pressure source, no drive. The primary source of hydraulic pressure is the front pump, which is driven by the engine by a pair of tangs on the outer sleeve of the torque convertor shaft. The front pump runs at all times when the engine is running. The secondary source of hydraulic pressure is the rear pump, which is driven by the output shaft of the transmission, and which delivers pressure whenever the car is in forward motion. The main reason for having a rear pump, in my understanding, was to provide a pressure "signal" to the valve body that was speed-related, in order that gear changes could be properly controlled. Nevertheless, the rear pump will, at sufficient road speeds, develop enough pressure to apply the servos to engage the drive through the gears. The torque convertor will act as a fluid coupling when driven on the over-run, and apply enought torque to the engine to spin it over so it can start. I don't know if the direct-drive clutch in the torque convertor will apply under push-start conditions, but it is not necessary that it apply in order for the car to start. (Other brands of auto transmissions which lacked the direct-drive clutch, but which DID have a rear pump, could also be push-started.)

Hope this helps.

Gord Richmond, within Weasel range of the Alberta Badlands

[wfsiew]

GOOD! Clearly explaination,Thanks for your infomation about the push start by the rear pump...ANyway, i'll will appreaciate to your info about this and hope can useful in future!



[quote]quote:Originally posted by gordr

Originally posted by wfsiew

Could u explain clearly how does the "output shaft pull the input shaft" in order to get turn to turbine, impeller & engine as well,Pls?

Well, I'll try.

The automatic drive has a torque convertor, and a 3 speed hydraulically-controlled transmission. Gear changes in the transmission are effected by hydraulic pressure applied to servos (simply devices that turn hydraulic force into mechanical action) which apply the bands or clutch packs. Bands are used to brake some elements of the planetary gearsets, and clutch packs are used to couple other elements together. There is also a direct drive clutch in the torque convertor that locks it up for economical highway cruising.

In any case, no hydraulic pressure source, no drive. The primary source of hydraulic pressure is the front pump, which is driven by the engine by a pair of tangs on the outer sleeve of the torque convertor shaft. The front pump runs at all times when the engine is running. The secondary source of hydraulic pressure is the rear pump, which is driven by the output shaft of the transmission, and which delivers pressure whenever the car is in forward motion. The main reason for having a rear pump, in my understanding, was to provide a pressure "signal" to the valve body that was speed-related, in order that gear changes could be properly controlled. Nevertheless, the rear pump will, at sufficient road speeds, develop enough pressure to apply the servos to engage the drive through the gears. The torque convertor will act as a fluid coupling when driven on the over-run, and apply enought torque to the engine to spin it over so it can start. I don't know if the direct-drive clutch in the torque convertor will apply under push-start conditions, but it is not necessary that it apply in order for the car to start. (Other brands of auto transmissions which lacked the direct-drive clutch, but which DID have a rear pump, could also be push-started.)

Hope this helps.

Gord Richmond, within Weasel range of the Alberta Badlands

[MarkC]

[65cruiser]

Kind of unrelated, but from what I'm reading about the rear pump this tells me that you could easily flat tow one of these with a towbar. You can't do that with many cars of today without benefit of an external electric tranny pump.

Hmm, maybe I should think about a Studebaker dinghy behind my motorhome[]

________________________
Mark Anderson
1965 Cruiser

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