dat521gatherer Posted March 14, 2014 Report Share Posted March 14, 2014 I'm thinking this is impossible but.... 75 B210 A14 Auto. The tranny has been leaking or loosing fluid with no huge puddles only a minor drip from the weep hole. So I check the oil the other day and there was like 3 gallons of fluid in it. There was so much in it the pistons must have been floating. I drained and refilled under to the full line and I just checked it and it was over the fill line. I only found one possibility online, does this sound possible? From trust my mechanic.com THE PROBLEM IS VERY SIMPLE ----yOUR TRANS HAS A VACUMME MODULATOR ON IT --ONE OF THE FEW THAT STILL DOES--- ANYWAY THE MODULATOR IS BAD AND THE FLUID IS BEING SUCKED UP OUT OF THE TRANS AND INTO YOUR CYLINDER CLOSEST TO THE VACUMME--THIS WILL WASH OUT THE RINGS LETTING THE FLUID DRAIN INTO THE OIL PAN ---AND ALSO WILL CAUSE YOUR VAN TO SMOKE AS WELL AS MAKE THE TRANS STOP PULLING WHEN IT GETS LOW. Quote Link to comment
Guest Rick-rat Posted March 14, 2014 Report Share Posted March 14, 2014 Sounds legit, did you check the level in your tranny, I don't think it holds 3 gallons of fluid. tranny should be slipping and exhaust smell like tranny fluid and blowing smoke when engine is running Quote Link to comment
datzenmike Posted March 14, 2014 Report Share Posted March 14, 2014 Check the auto trans fluid level. I doubt this is it as it would burn rather than getting past the rings. Pull the fuel pump off and see if the diaphragm has ruptured. That might be fuel mixed with the oil. Did or does the old oil smell like gas??? Quote Link to comment
Guest Rick-rat Posted March 14, 2014 Report Share Posted March 14, 2014 ^^^^ sounds more plausible^^^^^^ Quote Link to comment
DanielC Posted March 14, 2014 Report Share Posted March 14, 2014 Yes, that is very common on a automatic transmission witha vacuum modulator. The vacuum modulator tells the transmission how hard to shift. At WOT, you want very hard firm quick shifts. On the other hand, driving in city traffic, you want a nice soft "mushy" shift. The vacuum modulator does this. It also controls the hydraulic pressure in the transmission. If the transmission hydraulic pressure was high all the time the gas mileage would suffer. There is just a rubber (neoprene) diaphragm between the pipe going to the intake manifold, and the oil in the transmission. If it get a hole, the engine vacuum will suck the transmission dry, if you let it. 1 Quote Link to comment
datzenmike Posted March 14, 2014 Report Share Posted March 14, 2014 Our old straight six Ford van drained the ATF into the motor. Dip stick kept going up an tranny down. After adding 3 qts we sent it in. Modulator valve was bad. I can't see how it does it but... Gatherer... the Nissan automatic modulator from almost any auto will work. (not the one from the zx turbo though) Quote Link to comment
dat521gatherer Posted March 14, 2014 Author Report Share Posted March 14, 2014 Awesome. Before I found this I was trying to wrap my brain around how the converter could be throwing fluid past the rear main seal. It was blowing smoke before I drained the pan of it's multi gallon contents. I accused my daughter of putting oil in or letting her friends put oil in the car when the oil level was over an inch above the full line. Crap now I have to apologize to her. I was about to have the tranny shop do the front seal on the trans. I'll get a new modulator on and report back in a few days. Quote Link to comment
datzenmike Posted March 15, 2014 Report Share Posted March 15, 2014 This thing. There will be a small rubber hose elbow and a hard line connecting to the intake. Inside is a small needle so unscrew carefully. Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 any idea what the difference is between a 1 1/4 and a 1 1/2 modulator? No colored stripes on either. Both are screw in and adjustable for the same aplication.. Quote Link to comment
datzenmike Posted March 18, 2014 Report Share Posted March 18, 2014 Most applications are the same but the 280zx turbo automatic modulator is a much different part number. In fact the whole automatic is different inside. There are extra clutches and plates, the gearing is different, the output spline is larger the line pressure is higher, the modulator valve is stiffer? HD? shifts harder or faster with less 'softening' and slip and the torque converter has a higher stall speed. Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 Ok I matched the old one to the smaller 1 1/4 I hope this works. Quote Link to comment
ggzilla Posted March 18, 2014 Report Share Posted March 18, 2014 You can test the old one to see if it holds vacuum Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 Now it doesn't shift out of first while in D. If I put in in 2nd it will go in. What is the adjustable part of this modulator do? Screw the outer nipple one way for harder or sooner shifts ect? Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 You can test the old one to see if it holds vacuum I don't have a vacuum tester but I did blow and suck on the old one with no apparent leaks. Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 Transmission fluid did come out of the vacuum line when I took it off. Quote Link to comment
ggzilla Posted March 18, 2014 Report Share Posted March 18, 2014 > I did blow and suck on the old one with no apparent leaks. Hmmm. Probably only leaks under high pressure or high vacuum. Quote Link to comment
dat521gatherer Posted March 18, 2014 Author Report Share Posted March 18, 2014 The adjustment was screwed all the way in and didn't want to come out. Looks like some thread locker or elmers glue on the threads I screwed it out a lot then started screwing it back in 3 times. It still shifts early. . All 3 gears shift but 2nd is shaky. Now I have too much fluid in it and cant find my little pump sucker thingy. I'm calling it a night. Quote Link to comment
datzenmike Posted March 18, 2014 Report Share Posted March 18, 2014 Trans over filled? Just undo one of the cooler lines at the rad and run engine to pump it out into a container. Quote Link to comment
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