Madmarek Posted August 15, 2014 Share Posted August 15, 2014 I have a 1970 with extremely soft shifts. Put in B&M Transpak with no difference. replaced the Vacuum modulator no difference. So I removed the Vacuum line from the modulator and no difference. I would have thought that the trans would have shifted real high if at all with it disconnected. Any thoughts? Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted August 15, 2014 Share Posted August 15, 2014 what about when you manually shift it? with the installation of the transpack should've made a big difference wind it up in first gear and level off (build vacuum) then shift it, if it still doesn't have a firm shift I would consult a trans shop I have a feeling your tranny is living on borrowed time Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted August 15, 2014 Share Posted August 15, 2014 By short shifts I assume you mean shifting early? have you checked the governer to make sure its operating correctly? With modulator vacuum line off you shouldnt get an upshift or a very delayed upshift. And not to insult you are you sure its a th350 and not a th400, thats a whole different game. Hows the fluid look? and any slipping when its cold in low or reverse? sorry more questions than answers. Quote Link to comment Share on other sites More sharing options...
Madmarek Posted August 15, 2014 Author Share Posted August 15, 2014 If I manually shift it acts the same way. No pop to the shift just eases into it like a caddillac. I did reduce some weights from the governor and that raised my shift points but still soft. Yes it is a 350 since the oil pan gasket with the kit fit. Fluid looks cherry red. No smell. If anything I think it may slip a little in reverse but im not sure what size my torque converter is. I was hoping that by taking off the vacuum line it would change something but i was wrong. Quote Link to comment Share on other sites More sharing options...
Jason72 Posted August 15, 2014 Share Posted August 15, 2014 what is your line pressure? Jason Quote Link to comment Share on other sites More sharing options...
Madmarek Posted August 15, 2014 Author Share Posted August 15, 2014 I have not checked vacuum pressure but with a hand vac pump i did verify that the piston in the vac modulator moves. But I would think that if the vac line is disconnected the modulator in the trans would be fully forward since the vac modulator is pushing full force. Quote Link to comment Share on other sites More sharing options...
Jason72 Posted August 15, 2014 Share Posted August 15, 2014 I mean the fluid line pressure in the trans... Quote Link to comment Share on other sites More sharing options...
Madmarek Posted August 16, 2014 Author Share Posted August 16, 2014 I have no idea how to measure that. Quote Link to comment Share on other sites More sharing options...
Jason72 Posted August 16, 2014 Share Posted August 16, 2014 use a pressure gage installed in the yellow port in the picture, then check pressures in ranges per the chart. https://dl.dropboxusercontent.com/u/79843481/th350.jpg https://dl.dropboxusercontent.com/u/79843481/pressures.jpg Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted August 17, 2014 Share Posted August 17, 2014 In that kit I assume they had you change the shift cousion springs in valve body, was there different options for the springs or just one choice? Quote Link to comment Share on other sites More sharing options...
Madmarek Posted August 18, 2014 Author Share Posted August 18, 2014 Nope just one spring. One thing I did not do was file the separator plate. How necessary is that to do? Also how do you do the above measurements at full throttle per the chart? Quote Link to comment Share on other sites More sharing options...
Jason72 Posted August 18, 2014 Share Posted August 18, 2014 Take the measurements while driving the car. How were they at idle? Make sure you are at operating temp. Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted August 20, 2014 Share Posted August 20, 2014 Not sure about fileing seperator plate. Quote Link to comment Share on other sites More sharing options...
Jared Richey Posted August 21, 2014 Share Posted August 21, 2014 My Car has a 3500 Stall, and the Trans is built with a shift kit, but the shifts are not as kick in the pants as my stock 70 350 300 HP with a shift kit. Quote Link to comment Share on other sites More sharing options...
zmanabba Posted August 31, 2014 Share Posted August 31, 2014 The shift kits from B&M are designed to be used with a high stall converter and will feel softer when paired up this way. I remember when I was younger and couldn't afford anything other than a stock converter how the whole car would shake when it did the 1-2 shift. I loved it. My girlfriend not so much lol. Reminiscing aside I too have a feeling the transmission is on its way out. Reverse takes the highest amount of pressure to engage so if you feel that it is slipping in reverse that could be a sign. If you do end up rebuilding it make sure you swap in the shift kit and you will have a transmission that will out last the car. From what I remember filing the separator plate is to make sure it seals correctly and there is no leaks between the fluid channels. In this case I don't think it is the problem. David Quote Link to comment Share on other sites More sharing options...
Madmarek Posted September 17, 2014 Author Share Posted September 17, 2014 Still bugs me that the vacuum modulator seems to be doing absolutely nothing whether it is connected or disconnected. Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted September 17, 2014 Share Posted September 17, 2014 Is that an adjustable modulator thats on there, some are? May want to check that. Quote Link to comment Share on other sites More sharing options...
Jason72 Posted September 17, 2014 Share Posted September 17, 2014 How were the pressures?? If the pump can't make pressure or there is an internal leak the modulator isn't going to do anything. Quote Link to comment Share on other sites More sharing options...
Daryl Posted September 18, 2014 Share Posted September 18, 2014 I did a kit not that long ago, fileing the plate I think refers to the holes drilled and removing any burrs left over. Quote Link to comment Share on other sites More sharing options...
Madmarek Posted September 18, 2014 Author Share Posted September 18, 2014 Good point on the pressures. I have not been able to rig anything up to be able to read pressures as of yet. Most of the kits seem to talk about filing the plate to make sure its completely flat and seals properly. Quote Link to comment Share on other sites More sharing options...
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