62 Galaxie 500. 390 w/cruise-o-matic MX 3 speed

I apologize in advance for not having a great knowledge of old cars or car modifications. I have experience in car repair, but have never ventured from just replacing whatever breaks on the vehicle.

1) Is my transmission ok?
The transmission torque converter appears to lock at maybe 50-60 mph for whatever reason. Shifts at 35mph into second gear, then shifts at 65mph into third gear. That seems like a pretty late shift, but I guess its ok??? If you’re in the 50-60 mph zone and let off the gas, the torque converter seems locked, and thus feels almost like the brakes are on and the car slows down fairly rapidly. At some point the torque convert lets go and all is well. I know its not the brakes or other mechanical parts binding to slow the car, as the car doesn’t do this in first gear. I found one other person online that described this exact scenario and he seemed to think it was normal, is it??


How do I check the level of fluid? Normally I’d run the car 15minutes and then while the car was running and warm check the level. My understanding is that type F trans fluid contracts with heat (unlike merk fluid which expands), so do I still run the car for 15 minutes to get it warm and the check it while its running? If I do that the dipstick reads nothing, completely dry. I’m assuming its type F fluid. Its pink and looks like normal transfluid, so I’m guessing its not brake fluid or mineral oil.


2)
I want to put a power booster for the brakes on the car but don’t know the full implications. Right now it’s got 4 drums that work alright, but at decent speeds its alittle nerve racking for sudden or hard braking.

Questions:
-Does anyone have a good condition booster?
-Who makes a good aftermarket booster?
-Where do I pick up the vacuum connection from on the engine? Do I have to splice into another vacuum tube?
-Will the booster effect how the brakes currently work in the 4 drum setting? Ie will I need to mess with the proportioning valve or anything else after the booster is installed?
-I have a booster from a izuzu trooper, its not an exact fit, but looking at it I think I can get it on there, would this be a problem to use? Ie would it create too much pressure in the brake lines, or not enough, or not work at all? It has the ABS control box, but I was thinking I’d take that part out. I realize under this option I’d have to do alittle fabrication work to get the mechanical connection to fit, but the booster seem like such a simple thing I thought I might be able to get away with just using the one I have.

 

The old cruisomatics are expensive to rebuild, but the seals are getting weak in yours. The fluid should be type (F). It should read full on the stick when hot. Be sure you are on level ground when checking. An upgrade would be to go with a C-6 trans These came out in 1966, so it wouldn't be correct for the car, but it's a much better trans and parts are available. You would need to make some modifications to linkage and use the C-6 flex plate. This is assuming you have the 352 or 390 engine. There isn't a C-6 available for the old (Y) blocks, unless the mount pattern is the same and I don't think it is.