ThirdMC Posted July 28, 2010 Share Posted July 28, 2010 O.K., Before I have someone tear into the tranny thought I'd ask here. Former owner put a Jegs convertor and TCI shift kit in. http://www.jegs.com/i/JEGS/555/60400/10002/-1 http://www.jegs.com/i/TCI/890/326200/10002/-1 The car shifts really soft and seems to shift a little too early. He also never hooked up the tranny kickdown linkage. Any ideas on what I should check? Quote Link to comment Share on other sites More sharing options...
amsterdam84 Posted July 28, 2010 Share Posted July 28, 2010 Check fluid level and if its a th350 the vacuum line going from the intake to the tranny. That line if disconnected or broken will cause early shifts even at WOT. Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted July 28, 2010 Author Share Posted July 28, 2010 Thanks, gonna have it on jackstands to change the springs and shocks later this week. I'll check that while I'm at it. Quote Link to comment Share on other sites More sharing options...
Mike 57 Posted July 28, 2010 Share Posted July 28, 2010 Some higher stall converters make the shifts seem soft until you are on it and above the stall Quote Link to comment Share on other sites More sharing options...
amsterdam84 Posted July 28, 2010 Share Posted July 28, 2010 Some higher stall converters make the shifts seem soft until you are on it and above the stall  I have that happen sometimes as well. I dont have a high stall converter but when I shift around town under 1000 rpm I barely feel it but when the go pedal is pushed I can usually squawk the tire from first to second. Quote Link to comment Share on other sites More sharing options...
wallaby Posted July 28, 2010 Share Posted July 28, 2010 The kickdown linkage will regulate shifting also. Between the information the trans gets from the position of the throttle (kickdown linkage) and the load on the engine (vacuum modulator), the transmission does its best to shift at the right times. If the trans thinks you are accelerating slowly it will shift early and soft. An adjustable modulator can help. You can dial them in to delay and firm your part-throttle shift points. First I'd make sure your stock parts are hooked up and working, then go from there. Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted July 28, 2010 Author Share Posted July 28, 2010 Will do, Thanks guys! Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 29, 2010 Share Posted July 29, 2010 mike you got that backwards.. a disconnected vacuum modulator will produce late hard shifts.  if it's shifting early and soft, i'd take a look at the govenor in the side of the case, and remove the vac. mod and put a vacuum pump on it and see if it's moving correctly. (no more than 15 inches or you'll rupture it)  it is generally a good idea to keep the TH350's kickdown cable hooked up.. it uses that to control shift firmness too  Quote Link to comment Share on other sites More sharing options...
amsterdam84 Posted July 29, 2010 Share Posted July 29, 2010 Tim, when my vacuum mudulator was disconnected it was shifting way to early. I could put the pedal to the floor and I'd be in third by 30 mph. Perhaps I am an exception to the rule? Just personal experience. And the shifts were soft. Â Also isn't the kickdown cable end slotted? It shouldn't be engaged until you push the pedal far enough right? Quote Link to comment Share on other sites More sharing options...
wallaby Posted July 29, 2010 Share Posted July 29, 2010 Usually if the modulator is unhooked it sees zero vacuum...the same conditions you get when the throttle is wide open. When the modulator thinks you are wide open, it delays the shifts. There must be a connection with the position of the kickdown linkage...maybe it needs to be pulled all the way out to also signify wide-open throttle and get the normal delay in shifting? Â Anyway, it sounds as if the two work together to control the shift points. The kickdown does have a slotted end...and a correct bracket that bolts to the manifold or carb feet. The slot is there to prevent downshifts unless enough throttle is applied. Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted July 29, 2010 Author Share Posted July 29, 2010 Got a new kickdown cable, slotted part broke on the original. I'm gonna try to get it installed this weekend and see what happens then. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted August 1, 2010 Share Posted August 1, 2010 there is something wrong with your vacuum modulator if you are getting early shifts with it disconnected. Â Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted August 1, 2010 Author Share Posted August 1, 2010 Got everything done on the car now except the kickdown cable. I know it hooks onto an 'S' in the tranny but no matter how hard I pull I cant get it to pull out far enough to unhook it. Can't even see the 'S'. Am I doing something wrong or do I need to drop the pan in order to unhook it? Quote Link to comment Share on other sites More sharing options...
kc8oye Posted August 1, 2010 Share Posted August 1, 2010 it's not really an S.. it's more of a stretched out 'z' Â sorta like this.. Â Â __|-- Â Â does the cable itself pull out and spring back? if not, it's possible your 'kick down valve' in the trans is stuck which would explain the early shifts... also, it only comes out to about the top of the case.. doing it in the car will not be easy! Quote Link to comment Share on other sites More sharing options...
ThirdMC Posted August 1, 2010 Author Share Posted August 1, 2010 It will pull out maybe a couple of inches or slightly more and if you let it go it will spring back most of the way. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted August 2, 2010 Share Posted August 2, 2010 ok.. that sounds about right. Quote Link to comment Share on other sites More sharing options...
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