looking for a 1950 oldsmobile rocket 88 hydramtic transmission modulator valve.
not having luck finding one. anybody know where I can buy one
or know the part number. Thank you.

 

Have you checked at Fatsco?

https://www.fatsco.net/

 

I'm not sure what you are calling a "modulator valve.
Here are a few illustrations of early Hydra-Matic's.
Please tell me the four digit number associated with the part you want.
Then I can give you a part number.
Click on the pictures to make them larger.

 

I guess it`s called a vacuum modulator.
the car is in a warehouse.
will have to go look at the car tomorrow.
and check for a part number on car.
could I be wrong and the 1950 hydramatic transmission didn`t have vacuum modulator ?
the transmission is shifting slow and sometimes it has difficulties going from reverse back to drive.
mechanic told me the vacuum modulator might be bad.
so I wanted to buy one before I go to the warehouse.

 

Find another mechanic.
If he doesn't know that an early Hydra-Matic doesn't have a vacuum modulator, then he doesn't belong working on one.
The first thing I would try is changing the fluid and filter screen.
Use only Dexron III/Mercon fluid.
It should take about 11 quarts to fill if drained completely.
The torus (torque converter) can be drained by two plugs in either side of it.
The 70 year old fluid in it may be gumming up a shift valve.
Pull the pan and change the filter screen too.

The picture that you show is a '65 or up Turbo-Hydramatic 400. That isn't what's in your car is it?

 

Thanks fellas for all your information. I will drain the fluid and change filter as suggested.
no , that is not the actual transmission in my car. just a picture of a transmission with a vacuum modulator.

 

^^^THIS^^^

There aren't many shops left that can service the early automatics.

 

Interesting article and thank you for posting the pictures. I have recently got a 1950 88 convertible. I can’t find the panel that hides the indicator which I take it is the fill point. Do I have to remove the front seat / carpet?

 

The panel is located under the carpet .
It's on the right hand side of the transmission tunnel.
You don't have to remove the front seat. But sliding it all the way back will ease access.
The passenger side carpet must be peeled back far enough to expose the trans tunnel.
Yes, the fill point is the dipstick tube.

Olds didn't make it easy to check their early transmissions.
It wasn't until 1954 that the trans level could be accessed under the hood.

 

Thanks Charlie,

Found it! The fluid looks clean but it has been overfilled which might explain the reluctance to go in to revers.

 

Did you check it with the engine ticking over in neutral?

 

No! I’ll do that and let you know the result.

Many thanks

 

With the engine ticking over in neutral the fluid level is correct. Fluid is pink in colour.

 

Since you may not know when the fluid was last changed.
It may be a good step to go ahead and change it.
There's a plug on the pan, and then the torus (torque converter) is drained by two plugs on either side of the flywheel.
Remove one plug, then rotate the engine so that the other plug is on the bottom and remove it also.
Refill with about 11 quarts of Dexron III/Mercon fluid.
Oldsmobile recommended that the fluid be changed every 30.000 miles.