Hello everyone! I've been searching the forum for a solution to my symptoms after the rebuild to no avail... Following the workshop manual and a youtube video I've rebuilt my leaky C4 on my 74 mercury comet 250cid. Following the issue I've again removed and disassembled the transmission this time with my dad's help and we couldn't find anything. What's wrong: Following the rebuild It doesn't shift into 3rd(so it seems), putting the column shifter into 1st or 2nd it shifts fine. Putting it into Drive makes it not want to shift into 3rd(Or maybe even 2nd, I'm not sure), the engine makes a noise as if it's in neutral but giving it throttle does pull the car forward(be it slower than normal). If I start with 2nd then once up to speed shift it into Drive, it'll switch into 3rd gear. On a quick note the kickdown is disconnected since I've swapped to a Holley 350 carb. What I've done to it: I've disassembled the transmission up until the one way clutch(Front side of tranny) and from the back till I've reached the governor distributor sleeve(Back side of tranny). I've replaced all the rubber seals making sure to match them with the old once, replaced the steel oil rings on the governor and stator support, replaced clutches and replaced the intermediate band. As for the valve body I've replaced 3 of the rubber balls inside and a single rubber puck, making sure to place them in the correct positions according to both how they were when disassembled and using the manual for guidance. replaced the gasket between the two halves and called it a day. I hadn't tinkered with any of the valves. Checks and confirmations: Following the issue I've been searching the internet for answers, so here are a few things I feel confident asserting as properly done(Hopefully.....) Bench air testing the case: Following the workshop manual and a youtube video I've air pressure the tranny on a bench(After taking it out for a 2nd time) I've measured the lowest psi needed to engage the different components -Forward Clutch - 45 psi -Reverse High Clutch(Some call it Direct clutch) - 20 psi Intermediate servo apply(Applies the intermediate band) - 20 psi (Does not hold pressure, pressure leaks and slowly disengages the band) -Governor out port - 53 psi -Low reverse servo(Applies the reverse band) - 10 psi (Holds pressure till I remove the air nozzle) Checking end play(Out of spec): Following the workshop manual and a youtube video I've checked the end play using a dial indicator, it came out at 0.062 inches. Spec is 0.008-0.042, I know it's out of spec but will it cause such an issue considering I haven't changed any of the washers and made sure to place the correct once. I imagine the play would be the same as before I've rebuilt it. Band adjustment: Intermediate band - 10 ft.lbs then backed off 1 and 3/4 turns Low-Reverse Band - 10 ft.lbs then backed off 3 turns Following that video and the workshop manual. I tried giving the intermediate band another 1/4 turn in, making it 1 and 2/4 turns out in total. In hope that it'll help, didn't seem to make a difference. Valve body balls/gasket/: Checked the 3 balls and puck and I'm certain they're in the correct spot, same as shown in the workshop manual, and as I've taken the old once out. The old once were smaller but I've read that it's normal as they degrade. the valve body's gasket is the correct one as all the holes line up with the steel plate between the valve body parts. Vacuum modulator: I kept the old vacuum modulator(I've replaced it a year ago) it has two hoses connected to it. Thicker line goes into the manifold vacuum, thinner one is also connected to the manifold vacuum because I've removed all the emissions stuff in the car. Transmission oil: I've used the same oil as before Valvoline ATF as it worked fine so far. Checking the oil with the engine running seemed to be between the lines. All in all I've put very slightly under 2 gallons into it. On a finishing note, I really appreciate anyone who took their time to read this! thank you! I'll appreciate any help or ideas as to what I could check or maybe if anyone knows what could cause such symptoms
I'll bet this is incorrect, connect the large line to manifold vac and leave the small disconnected. May not fix the problem but currently you have vacuum fighting for operation of both diaphragms in valve.
I have planned on replacing it, I got a single line one from the kit. I wasn't sure if I should replace it since it technically worked just fine before the rebuild and so I wanted to refrain from changing unnecessary parts until the rebuild was complete and the car was running. Thank you for the suggestion, I will change it out once I get the tranny sorted out
Is the kickdown linkage adjusted properly? The C4 doesn't use it as a throttle valve in the way some transmissions do, so not having the kickdown linkage won't destroy the trans. If the lever is in the wrong position, however, it will delay upshifts.
Put the C4 back in the car yesterday, I've decided to reduce the end play seeing as it was out of spec. I've put a washer that I've cut out of sheet metal under washer #2, lining up the notches in it and everything. That took the end play down to 0.026 which is within spec but clearly my thrust washers are worn so I've ordered some new once. The car still has issues shifting in drive, but it started shifting normally once it's warmed up, I imagine it's because the metal expands and so the oil pressure increases. I'll replace the thrust washers and hopefully that'll do the trick.... I've checked the kickdown, although the kickdown is disconnected, the kickdown lever in the tranny is supposed to push a small spring loaded rod in the valve body. That lever doesn't seem to reach the rod so I imagine it isn't the kickdown. Thank you for the suggestion!
put the rod in behind the modulator? valve correct? what about the governor? clean? did it move freely once back installed to the output shaft?
