Pump gear

[85 Riviera]

I was just wondering for chits and grins, what is the differance between the 7 or 10 vain pump in a 200-4R and the gear pump style in my 325-4L. It just surprises me because the 325 and 200 are so alike they even share the same clutches,band and servos so why would my 325 have a gear pump like the old TH350's did?

 

[WE4]

save save save

Because they were smart!! A rotory pump such as yours is Wayyyyy more effiecent, forgiving and dependable. The vane style sucks. Period. No easy way to say it. SUCKS! The reason they went to it was to kill volume, inturn reducing load, for better economy. However, after shiitting a pump or two the difference in economy is eatin up. That is the long and the short of it. I wish these trannys ( 2004r's) had a rotory pump, and you know what? Gimme time boys, gimme time.........

LOL

Bruce
WE4

 

[85 Riviera]

Huh! good to know

 

[MeanBuicks]

Yep, the vane-style is variable displacement meaning at lower demand it pumps a smaller fluid volume whereas the involute-style is a positive displacement design. The faster it turns, the more it pumps.

Bruce, if you're looking at retrofitting a positive displacement design, consider a gerotor as it's a much better design than the involute. More efficient and robs less power per unit displacement than the involute. That's why our Powerglide pump wound up as a gerotor design.