904 shifting problems

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stroker_valiant

stroker_valiant

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The trans is stacking gears when put in drive.
I am running a 904 behind the stroker, it is freshly built, 3500 stall (9 or 9 ½) converter. The trans has a B&M shift kit. I have Lokar type cable for the throttle pressure, I have played with it to get it to shift right, and when it was set where it would shift ok, it limited my throttle travel. I dropped the tranny pan and adjusted the allen head screw with the spring pressure on it. (The name of the screw slips my mind) I have had the pan off two times trying to set the correct pressure, and the trans is still staking gears, and will not downshift when the pedal hits the carpet. I’m at a loss as far as what to do now, could it be internal problems in the valve body causing the shift problems? Any advice would be great
 
certainly sounds kickdown related. are you adjusting the allen head bolt to factory specs? I would do that and then if it is still incorrect, you must not have the correct kickdown linkage.
 
I have had the allen bolt set at the factory setting, and various points in between, and still no luck.

One thing I forgot to mention, the trans WAS shift almost properly, but it was shifting 1-2 fast, and holding 2-3 longer than it should, and I would have to let out of the throttle to make it shift 2-3. I’m kind of thinking it might be in the valve body, but still unsure.
 
What rpm does it shift at? My first guess is you need a higher rpm governor weight package and/or a different set of 1-2 and 2-3 shift valve springs.

The screw your referring to is the throttle pressure valve idle setting. It does not affect the rpm at which the trans. shifts at wide open throttle. Only affects the shift rpm at light throttle.

What do you mean by it's "stacking gears"?

BTW: I quit using B&M kits a long time ago cause some of them didn't work right. Very unpredictable.You may put in 3 or 4 and they work right and then put in the next one exactly the same way as the others and it not shift right. I only use Trans-go kits now.
 
When I said stacking gears, I mean the trans is shifting into third gear within a few feet of moving, as in no shift points. I'm fixing to take it back apart here in about an our, i'm determined to figure this out!!!
 
Try checking the throttle downshift linkage. This was happening to me for a while until I got it adjusted right.

Pretty easy to do depending on what kind of linkage you have (1 peice or three piece).

Pop the clip off and pull the linkage all the way forward to remove all the slack. Spin the yoke until the back of the slot sits right against the throttle level. Pop the clip back on and test drive.

I get to go underneath this weekend and retighten all of the trans pan bolts.....not sure why they keep loosening up. I have set them to 95 in pounds, but I am under every 2-3 weeks retightening. Might try some thread locker on them this time.
 
You could have internal pressure loss through worn parts that werent replaced, or you could have valve body programmign issues. Best way to tell is to have the pressures tested and recorded. Otherwise you're just making a ton of effort and shooting blind. If I had to guess, you have an issue with the high gear clutch or servo, or the reaction shaft/forward clutch retainer sealing rings. You can also try sticking a known good valve body into it to see what it does.
 
Sounds like you have the kickdown-linkage to tight.
Higher pressure = later shifts, because the high pressure makes the trans "think" you are driving at full throttle, and therefore delaying the shifts.
Try to give the throttle some space before the kickdown-linkage starts operating, so that you don't have max pressure even when you have full throttle.

-Payy
 
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