Technical Hydramatic Fluid

Hey guys,

My caddy shop manual is at a friends house whos not available at the moment.

Im about to change the trans fluid in my 50 cadillac hydramatic.

Does anyone know how many quarts ill need?

Also, the modern dexron ATF is reverse compatible with previous dexron generations right? For example a V would be safe to use in a car that called for II. Correct?

Im draining the whole thing and dropping the pan as well, so Im not trying to mix any fluid.

Thanks

 

I beleive it's around 10 - 11 qts. I used Ford type F fluid. It will give you a more positive shift.

 

Thanks.

Would you guys believe I called 6 different cadillac service departments across 2 states just to ask if modern dexron works with previous generation dexron.

Not a SINGLE one picked up the phone. They all had a lady to transfer me to the department but not a single person picked up. How do they do business!

 

a 30 second Google search netted this

Dexron VI—the newest GM ATF, it was developed specifically for the new six-speed automatic and is a synthetic blend (meaning it has some conventional base stocks). That transmission has tighter internal tolerances and required a fluid that had higher shear strength that Dexron III.

It was introduced with the 2006 models. GM considers Dexron VI to be "backward compatible," meaning GM recommends it for use in any vehicle that originally used any earlier version of Dexron and that it can be mixed with them.

Do you really think that a Caddy dealer is going to know anything about a 65 year old car?

 

Yeah. I went to the dealer and got a nice older service tech who took me back and searched his computer for service bulletins that talked about the backward compatibility of modern dexron. He couldnt find anything but assumed it would be okay.

 

Called a shop in California that specializes in hydromatic rebuilds and I was told the Dexron VI would work fine.

 

You will have to drain the converter to change all the fluid.

 

Did that - thanks

 

If you still have questions about the capacity measure what you drain out and then refill to within a half quart of what you measured, just to ensure that you don't overfill the transmission. Then check your level and add if needed. Also I would go with Ford Type F fluid. Using a semi synthetic or full synthetic fluid in older transmissions might make it prone to seal leaks.

 

I remember old guys putting a couple teaspoons of brake fluid in with the new stuff - it softened the seals enough to help cut down seepage. Don't know if I'd try it today ... and I damn sure wouldn't pour Ford fluid into it.

 

Well Im pleased to say the cadillac took well to the dexron VI. Shifts were nice and smooth. I dropped the pan and cleaned the filter and pan, new gasket. Adjusted the linkage some more and it down shifts from 4-3 now.

 

Old hydros used rings ( like little piston rings) for seals. I don"t think brake fluid would do much for a steel ring. Tell me again why type F is not good in a hydro. I ran type F in my Olds and it would spin the slicks on the 2-3 shift.

 

I am by no means a transmission expert, but I think I read type F fluid has more "grip" to it. Id be afraid itd be too much for the components of a 64 year old transmission.

 

I also use Type F in my Hydro flat plan, shift's as hard as you want or you can adjust the tv with a veneer cable
55 Pontiac hydo is a tank.