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Push starting an automatic?
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Author:  Jopapa [ Wed Feb 12, 2003 10:39 am ]
Post subject:  Push starting an automatic?
A guy on one of my mailing lists posted this during a discussion about the pros and cons of wheeling with an automatic tranny. Does this strike anyone as weird? I would think that unless there's something wrong with the torque converter, push starting would be out of the question.

Here's the quote:
"My dad had a '74 Dodge pickup with an automatic that we push started
all the time. Put it in drive and pushed - I don't know why it
worked and always thought it was weird."

Thoughts?
Author:  64 Convert [ Wed Feb 12, 2003 12:56 pm ]
Post subject: 
Older cars could be push started and I did it many times. I'm not an expert on transmissions, but I seem to recall it had to do if the transmission had a rear oil pump or not.
Author:  Jopapa [ Wed Feb 12, 2003 2:21 pm ]
Post subject: 
Quote:
Older cars could be push started and I did it many times. I'm not an expert on transmissions, but I seem to recall it had to do if the transmission had a rear oil pump or not.
Rear as in, driven by the input shaft of the tranny instead of the engine's output shaft?
Author:  Doc [ Wed Feb 12, 2003 3:45 pm ]
Post subject: 
60-65 904 automatics have two oil pumps, I think the "cable linkage" 727 also has the two pumps. These have the Ball & Trunion type front u-joint.

The front pump is driven at engine speed via the input shaft / converter.
The rear pump is attached to the output shaft / driveshaft.
When you "push start" a auto trans with a rear pump, the output shaft turns the rear pump until it makes enough hyd. pressure to apply the clutch packs. At that point, the input shaft starts turning and works the converter "backwards" until the stall speed is reached, at that point, the engine will start to turn. All this takes a good amount of vehicle speed to make work. (30-40 mph)
DD
Author:  DusterIdiot [ Wed Feb 12, 2003 6:40 pm ]
Post subject:  My chilton's master manual even says...
All torqueflites from 1964-1970 can be push started by getting it up to 15 mph (must be thinking an incline...or a couple of husky guys...) and dump it into low. I know my grandfather did this once with a dead battery in his 66 Chrysler 300 (383-4v/727...), but it was on a hill...afterwards he proceeded to say something about the pumps being different and how nice a manual is when you need a push start...of course, I was like 10 at the time...

-D.Idiot
Author:  rustycowl [ Thu Feb 13, 2003 8:14 am ]
Post subject:  push start
I know we once coasted a '55 or '56 Chev wagon with a dead battery, until it started.
Author:  Slant Cecil [ Thu Feb 13, 2003 7:04 pm ]
Post subject: 
The GM powerglide had a rear pump up to around '64. After they were front pump only, no more push starts.

Cecil
Author:  Jopapa [ Fri Feb 14, 2003 12:22 am ]
Post subject: 
I still don't know how a '74 could've been push started :?
Author:  Dart270 [ Fri Feb 14, 2003 5:39 am ]
Post subject: 
I don't either. The 904 only had a rear pump until 1965, so any model after that (except maybe lockup??) shouldn't be able to do it.

Lou
Author:  Slant Cecil [ Fri Feb 14, 2003 7:16 pm ]
Post subject: 
Have you ever had your car on jack stands,motor running, trans in neutral? The rear wheels will turn, kinda like the trans is freewheeling. Maybe this freewheel effect will work backwards thru the trans. When pushing fast enough, is it possible the effect will turn the front pump fast enough to engage the motor? Pose this question to John Kunkel at Moparchat, he'll know, he's a Torqueflite guru.

Cecil
Author:  JustinT. [ Mon Mar 03, 2003 1:54 pm ]
Post subject: 
You mena maybe getting it up to 40 or 50 then dumping the gears? hmm....try that in my van, see if i blow the guts out of it. :roll:
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