Update on front seal.

so where's the 'rear pump' ?

"Trans surgeon" wrote: "So where's the rear pump?"

If here is one it's probably in the rear,but who gives a shit?

you missed the point completely.... there is no rear pump, hence no reason to call the pump the "front pump"

-Bret

good grief

Their routinely called the front pump because waaayy back in the 50's there was a front and rear pump on some of the earlier automatic transmissions.

nospam

yes

and the last unit built with a 'rear pump' was the 1964 PowerGlide

isn't 40 years long enough ?

transmissions.

I guess your right, lets bury the front pump speak. ;-)

nospam

Rolls Royce still makes (they own the license now) a version of the old (first generation) GM TH-400 that uses a rear pump. Some of the big trucks (tractors) that have automatic transmissions still have a rear pump. If an auto trans has a rear pump, you can push start a vehicle. Also with a rear pump you can have much better engine braking, which is why big trucks (tractors) have a rear pump. I am not positive but I believe the military

10-ton and up (maybe even the 5-ton) trucks with the auto trans also have a rear pump.

can you elaborate on this ?

"TranSurgeon" wrote

Ah ha.....my old 63 Rambler just got in under the wire then. It had a rear pump and I would occasionally experiment with starting it when it was in motion. Note: it would not start unless you were moving along at a reasonable clip, about

30 klms an hour if I remember, so actually push starting it with a bunch of people was out of the question.

Ian

'rear' pumps were nortoriously inefficient

Its a speed thing! With a rear pump you gain a lot of braking at slower speeds. One may not think that you would need engine braking at slow speeds, but if you are grossing 80,000 lbs + hauling coal down a mountain in Pa, WVa, Ky, etc. or iron ore out west, it is a necessity.

And 80,000 lbs is a light load, some go way higher. You can see trucks in downtown Detroit hauling steel to the auto plants, with 10 or more axles, that have to be grossing over 200,000 lbs.

what does the pump then do with this oil to brake the vehicle ?

in KY coal trucks run 120,000... and I'd bet not a single one of them runs an auto.

-Bret

I doubt it... as far as I can tell, michigan must have some rediulously low axle limits... I've seen 13 yd front dump cement trucks with 6 (1 steer, 2 pony, 3 drive) axles total... the exact same truck in New England would only have 4 (1 steer, 1 pony, 2 drive). when I was there a couple of weeks ago, I saw a (empty) flatbed trailer with 7 axles (just the trailer) turn onto Gratiot... God, didn't that thing howl.

-Bret

LOL... waaaayyy back in the 50's

transmissions.

actually thru 1964............

i was lol-ing at the fact that nospam said "waaaay back"..