Still dealing with third gear shifts in the Sunliner,four trans and none shifted right. Changed the cam and got some improvements but the third gear shift gets delayed when the trans warms up,was told the trans might be getting too warm so I am going to eliminate the cooler in the radiator and picked up the biggest cooler I could find to put in front of the radiator and will see how it does. I doubt the engine vacuum could change much but will be checking cold and then hot so anyone got any other ideas,the engine will be replaced with a Y block this winter and if I ever use it in anything else it will get a manual trans.
Sounds vacuum related to me. I would put a vacuum gauge on it where you can see it and see if it changes when it gets hot. It’s really kind of the only thing that makes sense if you asked me. The closer you put the vacuum gauge to the modulator the better. If it has kickdown linkage, make sure that is free and not being pushed until wide-open throttle. Other than that, unless the guy is putting the wrong seals in the direct drum or intermediate servo those are the only things I can think of.
It has a firm shift but it gets later as the trans warms up and no kick down linkage hooked up at this time,if the outside temp is under let's say 80 it will shift normal but if it's hotter then 80 it can do it. When cold it will be in third around 25 at light throttle but not when warmed up, trans only has a few hundred miles on it.
Talked to the guy that builds the trans for the shop and told him where it's shifting when warm and told me that is normal,I think I have gotten too used to late model trans so I am going to let it go and see what happens. My other vehicles have manual trans.
The trans should shift about the same warm or cold. If anything C4's tend to shift late when real cold. I too would connect a vacuum gauge and T it in right at the modulator. See what the vacuum is when it shifts okay and what it is when it is delayed. I remember the Rotunda trans test kit from Ford had a setup to T in at the modulator. You could also induce a vacuum leak to make sure the modulator was working correctly. Based on your trans guys comment, I think you may want to find another trans guy.
The speedo is about six miles per hour too fast now making me think something is wrong,put about 700 miles on it over the last two weekends and seems fine. The gear on the output shaft on this trans has a different amount of teeth then the other trans,I had the speedo correct on the previous trans but will deal with it.
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