727 Transmission: Use 46RE Pump Body for Higher Volume?

Hello All,

While researching info for my drag racing 727 buildup, I had a mopar guy and professional transmission builder suggest using the pump body from a 46RE, which has a higher volume pumping capacity. He said that the 46RE pump body can have the 727 reaction shaft support bolted to it with out modification and that this is a true bolt-in mod that affords a higher volume pumping capacity.

I hope I described that right...Anyway...

Anyone heard of this or done this?

Thoughts?

Thanks!

What conv are you going to use.. I used a 5000
stall 727 in a 518 trans for the street/strip..
I changed the pump (used a 727 pump and conv)..
there may be a increase in volume but you have
to make sure the spines match up and I dont think
they do because of that

No increase in volume - they have the same diameter and thickness rotors.
The 48 has better rotors and provides more volume. But don't use the 48 diesel pump housing, use the gas 48 housing in a gas application. The 48 has a rotor .100" larger in diameter so you have to machine the pocket diameter to use those rotors unless you score a Viper Truck gas engine 48 pump housing.

And......what do you hope to gain by providing more volume?

I was told the 46RE rotors have fewer, but larger/deeper lobes that move more fluid per revolution.

The service professional I spoke to owns Detroit Gearbox (Groesbeck and 8 mile). He's been doing transmissions and powertrain work for decades and is well versed with mopar tech.

I may not be relaying the tech information correctly. I will try and get some more info to clarify.

Thanks for commenting...

There is a difference in rotors from 1962 to 2003 on the 3 and 4 speeds that is true - as well as differences between the supports and pump housings as far as passages go which yield differences in restrictions.

The rotor designs provided for less parasitic loss - hence negligible loss in flow made up by the increased flow of the passage changes - so there was no net change in flow coming from the pump. The valve body and trans saw no change in flow. That's how it was explained to me by both the design and development engineers at work. I think they have more knowledge than anyone building transmissions for a living.

I didn't mis-understand the explanation - I have almost decades of experience too and well versed in tech as well.

And I'll repeat - why do you need more flow. Unless you have more leaks inside your trans or install larger and longer cooler lines - the fluid will just get regulated by the PRV with the trans seeing nothing for your work.

Thanks Transman, I appreciate your help.

I hope there was no offense taken by you or anyone else by me not knowing if I was explaining something that I don't fully understand , hence the reason why I was hoping to learn more through a post here.

Much thanks again...

Can you add any insight on the differences (if any) between a case for a lock up converter vs one without lock up?

I have a choice between two complete 727 BB transmissions (1975 and 1978) to use as a core donor for a SB 727 buildup.

I currently have a later year (I think 1979) SB front case to use and I'm wanting to verify if it's from a lock up or non-lock up application. Any visual differences?


So…can a lock-up converter case be used with internals swapped over from non-lockup transmission? (and with a low band apply transbrake)

Thanks!

PM being sent.
No offense taken - just hate to see people sold things they don't need.

What is the difference between an SRT10 48RE pump and the Cummins 48RE pump?

The quieting ramp machined in the pump pocket.