Hi There guys need your help .. got a few questions for you... I got my tranny back from the shop the guy came down and help me install it! good kid and great shop!.. hell of a deal too.. I got a different case as mine was cracked all the way around... new red alto eagle clutches// new kevlar bands.. a drum from a truck that uses 6 clutches instead of 5 a 34 element sprag, rebuilt pump. new bushings, and a fairbanks stage 4 shift kit set at street/strip Here's my question we took it out and tried it first at regular driving shifted great then a full throttle blast shifted awesome 1-2 and 2-3 then I let off and it dropped into second.. tried to get it to go back into 3rd wouldnt drop back in so we tried a different gov. different springs on governor thinking they were too light and drive was dropping out.. still nothing... finally one last time we drove it and it just would drop into second as we drove normally after trying a full hard run.. well driving back normally, I put it in neutral then back in drive and it went in had drive again... The only thing we can come up with is something is sticking in the valve body? not allowing the 2-3 shift to occur either way manually shifting or on the gov it doesnt shift into 3rd.1-2 is right there and tight! after that stays in second wont shift.. but let off put it in neutral and its there, but then drops back out after a bit... so we pulled it out and he took it back with him... Going to try a different valve body from another 400.. what are your thoughts.... I went back out tonight and measured the gov lands and the gov bore all seems to be fine not wore out.. both govs same measurement.. Is there any difference between my 74 case and this new 78 case? should be same right..
Just a thought here......otherwise I don't have a clue......but is your manual linkage adjusted properly? In other words, maybe it's set in a way that when you are in "D" it is still part way in "L2" or "N". Or perhaps the bushings are loose on the linkage causing it to not fully engage the stops inside the tranny. :idea2:
Does reverse work fine? If so, the direct clutch is working and the problem most likely has to do with the valve body or governor. As per one of the other threads out there, a problem may exist from using the little screens in the governor pipes. Seems like some guys have had them block up and this causes the trans to drop out of 3rd. Also, check the vacuum modulator and lines to the engine. If you have a leak or if the vacuum source is hooked to a "ported" vacuum port at the carb you will loose vacuum at light throttle. If using an adjustable modulator, maybe you can back off the set screw (counter clockwise) if it is turned in too far. This will cause late or no 3rd shifts. Good luck
Yes reverse works perfect!.. so does the 1-2 shift... Seems to me he said the other guy that built my trans 4 yrs ago did have that screen out its in now... We did also back out the screw atleast 1 1/2 turns no change.. and when shifting this manual that isnt a factor right? as its vacuum and its dropped out then.. vacuum is good to line. running same manifold vac i had before the trans failure
check this thread. http://v8buick.com/showthread.php?t=141319 It seems Yardley had the same issues and it turned out to be the screens. If the clutch works fine in reverse and when shifting manually (no slipping) it would seem that the issue has to be with low governor pressure not keeping the trans in 3rd. A sticking valve would not allow the trans to shift to 3rd at all. Low vacuum would also make late/hard 2nd gear shifts and a very harsh reverse as well. Governor pressure acts against modulator pressure to shift the trans. Backing out the modulator reduces it and should make the trans shift earlier and stay in gear. Switching governors would make a difference if the springs and weights were set to shift late on one governor. Sounds like a valve body issue to me. My best suggestion would be to drop the valve body and make sure it is assembled correctly. Make sure the accumulator rings in the 2-3 piston (I prefer metal rings, some like teflon) are not leaking and then put it back together without the governor screen. Good Luck
UPDATE!! Turbo 400 2-3 shift problem Awesome!!!....Shifts are very quick and firm!..and full throttle manual when i hit the gears its in there by the time i slide the lever!...1-2 is great and 2-3 is just as good quick and firm.. Just have to adjust my springs again on gov....So what fixed it? We are still leaning towards the collapsed gov Screen... but has a differnet VB and Solenoid too now....We couldnt find anything wrong with them either.. so I say that stupid weak Screen...Leave them out unless there the strong old style...Also On the lower gear set it hasnt lost anything! if anything it pulls harder now coming out second.. hard to hook in first roads are cold and the lower gears its smolder city! .. But the drop from first to second No difference on tach that i see from stock gears to this 2.75 set...Must be all that torque!
Glad to hear you had success! :TU: Am betting it was those crappy screens too. Likely not enough governor pressure to move the shift valves quickly thereby causing a slow clutch apply. When they blocked up more, the 2-3 stopped completely. Either use the old screen after cleaning it or leave them out. ou:
