904 no passing gear/ shifting issue

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SlantedDart

SlantedDart

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Hello, I have a few problems with my 904 trans. First no matter how I adjust linkage I can’t get passing gear to work. I believe the linkage is line pressure correct? Second it shifts way too fast. Almost seems to start in second.. messing with linkage seemed to make second gear stay longer but first was still way too short.
 
DO you know the correct procedure for linkage adjustment? Make sure the transmission lever is all the way back when the gas pedal is depressed to the floor. If it's not, adjust accordingly. If it is, then you will need to remove the pan and adjust the kickdown screw on the valve body. Your factory service manual will cover that.
 
If it's pre 1971 the 904 won't have a part throttle kickdown therefore you won't really be able to get into second gear at highway speed without manually shifting​
 
SlantedDart said:
I believe the linkage is line pressure correct?
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Throttle pressure, more accurately. Line pressure is adjusted inside the trans. The throttle pressure opposes governor pressure, more throttle pressure, longer till the shift. Tom Hand's excellent Torqueflite book has pressure test procedures anyone can do. A large face 300 psi gauge, some 1/8 NPT fittings and about 4' of high pressure hose are needed.
 
"First no matter how I adjust linkage I can’t get passing gear to work." There is only ONE (1) way to set it. Like Rusty said but I open the carb by hand instead of using the pedal. You set it like that then look for the problem elsewhere.
 
If anything in the kickdown linkage has been changed you may not have the right parts to make it work properly. Has the carb been changed from a two barrel to a 4, if so the 1st section of linkage is different lenght and possibly the throttle cable.
 
gm1236 said:
If anything in the kickdown linkage has been changed you may not have the right parts to make it work properly. Has the carb been changed from a two barrel to a 4, if so the 1st section of linkage is different lenght and possibly the throttle cable.
Click to expand...
I believe the carb was swapped to a Carter I have it at the carb shop right now being re built. You have a good point though. The slider shaft doesn’t seem to make sense for it..
 
Maybe its worth dropping the pan & inspecting the weld circled in red in this photo. I've come across a few where the weld had broken & the movement of the throttle pressure shaft was not moving the cam on the kick-down valve. The photo is of a 727 but they are very similar.

38347772gu.jpg
 
i just had this happen to me. Was shifting fine and then... not. There is a small E clip that holds the kick down lever shaft up in the proper relationship to the valve piston. in my situation, the E clip had popped off the shaft. it is located just below the throttle lever and above the the gear selector lever outside the transmission. if your throttle lever is at the top of the shaft then there is an opportunity for the the shaft to slide downward (without the E-clip) and then the cam will be below the piston. Something to keep in mind when you pull the pan.
 
Have u verified that when the gas pedal is on the floor that the cable is actually pulling the carb wide open. Pushing with ur hand on the carb is totally different. Have a helper press the gas pedal to the floor then verify. It’s easy not to have full throttle with a misadjusted cable. Let us know. Kim
 
Update.. dropped the pan and the little bird turd weld broke on the lever that pushes plunger in. It would catch sometimes then slip off the old tack. Used the tig welder to fuse it back together. All good
 
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