ktr530 Posted July 1, 2022 Share Posted July 1, 2022 I had a small leak in my transmission modulator, so I replaced it with a New Old Stock modulator. After replacing the modulator, it now doesn’t shift as well as when the old modulator was in there. I’m not mechanical, so I have a friend helping me with the project. When we blew air through the old modulator, the air flowed through like blowing through a straw. With the new modulator, you can feel resistance as I’m assuming the diaphragm is doing its job. We set the distance between the modulator and the transmission case at 3/8” and we’ve moved it back and forth with no success. Any suggestions? Thank you. Link to comment Share on other sites More sharing options...
Bloo Posted July 2, 2022 Share Posted July 2, 2022 (edited) What kind of a transmission is this? On the Borg Warner cast iron transmissions Rambler typically used, I don't recall any adjustment for case distance. Doesn't this just screw in and bottom out? The modulator usually has an adjustment screw that can be reached through the hose connection that adjusts the spring tension. The most obvious effect of adjustment is how early or late it shifts, and there are probably default settings in the shop manual. Shimming the modulator might have a similar effect? Or not? Somehow I don't think it's the right way. You need to suck on one of those to tell if it is any good, not blow. A mityvac or similar pump works well. It should hold vacuum. If you could blow through one, it is definitely bad, but don't use compressed air, that could easily blow the diaphragm out. It is usually obvious when they are bad because the vacuum line is full of transmission fluid. It wouldn't hurt to flush the line out if you see fluid in it when you replace a modulator. Edited July 2, 2022 by Bloo (see edit history) 2 Link to comment Share on other sites More sharing options...
ktr530 Posted July 2, 2022 Author Share Posted July 2, 2022 Bloo, Thanks for your reply. I don’t know what kind of tranny it is. I should have said when we suck on the modulator, not blow. 1 Link to comment Share on other sites More sharing options...
roysboystoys Posted July 2, 2022 Share Posted July 2, 2022 Probably a Borg Warner variation. Check to be sure you have vacuum at the hose end that connects to modulator. It might have come loose or torn the rubber at the engine supply. 1 Link to comment Share on other sites More sharing options...
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