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My 3T40 doesn't want to shift

Posted: Tue Aug 03, 2010 1:14 am
by Wanako
ok here's the issue. I got the my new 3.1 in the car and hooked up the old transmission and Torque Converter both of which worked beautifully before the swap.

Now after the swap, the engine runs solid and strong, but the trans doesn't want to shift to the next gear. More commonly from 2nd to 3rd. Example, I went on the highway and had it at about 30% throttle by the time i reached 45-50 miles per hour but the transmission kept holding on to 2nd gear and I was already at about 4800 RPMs. I tested it on the street and it will shift to 3rd when I'm BARELY tapping the throttle. My suspicion is that the Throttle Valve cable to the trans isn't adjusted correctly. Your thoughts?

Re: My 3T40 doesn't want to shift

Posted: Tue Aug 03, 2010 1:16 am
by Cliff8928
First, I would try and adjust the Throttle Valve (kickdown) cable.

Re: My 3T40 doesn't want to shift

Posted: Tue Aug 03, 2010 1:28 am
by Vampcrist
Yeah just go threw a double check all your connections as the first thing and I mean them all. Anything you disconnected make sure you check it. Could be something as simple as you missing a nother cable.

Re: My 3T40 doesn't want to shift

Posted: Wed Aug 04, 2010 1:19 am
by Asylum
It's a cable issue.

The kickdown cable is crucial in how a non-computer controlled trans works.

It's adjustable to a point but I'm guessing you have a kink in it somewhere.

Re: My 3T40 doesn't want to shift

Posted: Wed Aug 04, 2010 4:13 am
by Wanako
asylum wrote:It's a cable issue.

The kickdown cable is crucial in how a non-computer controlled trans works.

It's adjustable to a point but I'm guessing you have a kink in it somewhere.
I was hoping you'd see this considering you're like the #1 advocate of the 3t40. haha.

So i see many people agree with me that this could be the perpetrator. I'll look into it soon to re-adjust it and if it doesn't do it my cable's probably dead. I'll have to go to the yard to pick one up. Thank you gentlemen.

Re: My 3T40 doesn't want to shift

Posted: Sun Aug 08, 2010 9:27 pm
by Wanako
ok I adjusted the TV Cable and it was definetely way off. Now I also saw the Trans fluid and it was a bit dirty so I'll be replacing that along with the filter. My book says Dextron II or III but is there a better or upgraded fluid to use for the 3t40?

Re: My 3T40 doesn't want to shift

Posted: Sun Aug 08, 2010 9:35 pm
by Asylum
I use Royal Purple or at least I used to until I dumped 7 quarts of it on the starting line with my 3.94 doomed experiment.

Used Type F for a while to negate all the friction modifiers, but Billy has me using Dexron right now.

It's really all snake oil in that all it is is 10 weight oil with a bunch of detergents in it.

Buy good stuff and GET A COOLER! And then get one for the trans, LOL

Best thing you will ever do for your car.

Re: My 3T40 doesn't want to shift

Posted: Sun Aug 08, 2010 11:57 pm
by Cliff8928
GM recommends Dexron VI for all automatic transmissions and is what replaced the Dexron II and III specifications.

Re: My 3T40 doesn't want to shift

Posted: Mon Aug 09, 2010 12:15 am
by Wanako
Dexron VI it is. How many quarts of it does this thing take? also, when I drain it, does taking off the pan take out most of it or is there like tons of it hidden further into the trans?

Re: My 3T40 doesn't want to shift

Posted: Mon Aug 09, 2010 12:33 am
by Cliff8928
There's tons of it further in the trans, namely the torque converter. You might get out 5 quarts or so if i remember right (it's been a while since I've had an auto).

Re: My 3T40 doesn't want to shift

Posted: Thu Aug 12, 2010 1:26 am
by Wanako
Is there a way I can get it ALL out?

Re: My 3T40 doesn't want to shift

Posted: Thu Aug 12, 2010 1:28 am
by Cliff8928
without removing the transmission? Aside from a flush, no.

Re: My 3T40 doesn't want to shift

Posted: Thu Aug 12, 2010 2:01 pm
by Vampcrist
Yeah other then a flush the only thing you can do is drain it, fill it back up, drive for eh 250 or 500 miles your choice, and then change it out again. This way your diluding the old stuff thats remainging in the torque converter and with a second change you should have the most of it out.