For those of you who remember I built a tranny up for my wife about two months ago. Well the community college finally got it in! I built it to make my wife happy and to please me a little too. She wanted a tranny with shifts that were easy on her when she was driving around town and still perform if she decided to lean into the gas a bit. I wanted a tranny that I would never have to rebuild. It doesn't pay to build trannies for yourself. It shifts at the normal low speeds when you are light on the throttle- 1-2 shift at about 15mph (halfway through the intersection) and the 2-3 shift hits at about 20 -25 mph. The shifts are so fast that you don't realize it has shifted yet they are at a low enough speed that you can't feel it. The tranny holds onto the gears a bit longer when you are leaning into the gas a bit and you just feel the shifts because they are so fast. It's like going over the uneven cracks in the pavement. At full throttle it burns the tires in first and into second. the 2-3 shift happens at above the legal limits and chirps the tires as it goes into third. Going down the road at 40 I shifted to low gear to demonstrate the "select shift" function of the tranny and it when right into low without hesitation - bringing the engine rpm up to near the limit I am comfortable with in a car with 90000 miles on it. She is happy with it and I know it will outlast the engine that is in the car and probably the next engine it gets. These are the mods I made to it: Pump mods for more cooling and lube to the front half of the tranny. I reamed the rear cooling and lube passage for improved cooling and more oil to the rear lube circuit. Drilled a return passage to sump for the shaft seal and I drilled a hole for lubrication to the #9 thrust washer (which takes all the thrust in a C4 during acceleration). I drilled both clutch drums with seven holes to get better cooling flow and to let the oil exit when the clutches applied. I added a sixth clutch to the forward pack with .030 clearance and a fifth clutch in the direct pack with .025 clearance. I used a good welded intermediate band with the red "paper" (stock) type lining. The governor spools were polished and reinstalled - no mods. The valve body was reworked to provide for the "select shift" feature and the intermediate band accumulator was disabled. I drilled out the direct clutch restrictor, the intermediate band restrictor and the governor restriction just slightly to reduce the overlap between the gears. I installed a moderate main pressure regulator spring for a peak pressure of only 175 psi. The boost pressure valve and spring were left stock. I replaced the modulator with a yellow stripe unit and the pin was replaced with one at 1.6 inches long. The converter was replaced with a NEW stock unit and the cooler was flushed. The mods I made were more for longevity than for performance and we both got what we wanted out of the tranny. Talking to your rebuilder (especially if it is me) is the only way he can provide you with what you want. Now I can start planning my new tranny! It will be modded for longevity too but a bit more on the performance curve than my wife's - probably a stage two and a bit more governor than she has. (they will both be YELLOW though!) a side note: the instructor really liked the tranny and the way it worked, I wonder what he will think of mine....
Well Paul if the tranny didnt work right then she would have had to fire the tranny builder and that wouldnt be good now would it . Dang I wish you were just a little closer I would bring you a project. I have this old 24 spline input tranny(green dot) thats been in the shop twice and only got 10 miles out of the rebuild twice something to do with a manual reverse pattern valve body that it does not like, one of these days I will make a run up your way again and drop it of and let you play with it. Mike
Mike, Any time! You bring it up and leave it and I will call you when I think it will hold up. Bring your engine hp and torque specs with you so I know how far to take it. I'll buy lunch and we can talk about what you want and I can tell you what you need and then I will build it to make you happy. Then I will call you up and let you know when it is ready. Phone is 206.725.0881 - call to make sure I am home. Weekends are bad but weekdays I am usually home.
