Monteman1971 Posted June 30, 2008 Share Posted June 30, 2008 My turbo 400 won't shift again. It winds up a lot before it will shift. I had this problem a while ago and replaced the vacuum module and it went away. Think the module went bad again? Which way do I turn the screw inside it to maybe adjust it again to shift sooner? I've also heard that it's not good for the transmission to manually down shift it....anyone else hear this? Thanks, Steve Quote Link to comment Share on other sites More sharing options...
montecrazy1971 Posted July 1, 2008 Share Posted July 1, 2008 Steve, i have a adjustable modulator on mine and i have to unscrew it to make mine shift sooner. if that helps you Quote Link to comment Share on other sites More sharing options...
72MC Posted July 1, 2008 Share Posted July 1, 2008 Steve, unless your A/T is built to down shift like mine is(full race tranny), it is not good to downshift an A/T unless your rpm's are on the lower side. - Dave Quote Link to comment Share on other sites More sharing options...
John Burns Posted July 1, 2008 Share Posted July 1, 2008 Steve, B&M and TCI make governor recalibration kits that you may want to look in to- I have used the B&M with good results. http://store.summitracing.com/partdetail.asp?autofilter=1&part=TCI%2D326500&N=700+400252+115&autoview=sku http://store.summitracing.com/egnsearch....k=KeywordSearch Change your shift points. These governor recalibration kits will allow you to adjust the shift points of your transmission after it is installed in your vehicle. These kits are very useful for transmission swaps, or if you have a car that is very light, or has a low rear gear ratio. They also work great for bracket cars retaining an automatic 1-2 shift. I found this tidbit from another site: The vacuum modulator and governor work together to control shift points and shift firmness. If there is no vacuum supplied to the modulator, the trans will shift late and hard. As long as the vacuum modulator is connected to a vacuum port in the intake, it should work ok. The adjustment screw is a fine-tuning thing, it won't prevent it from shifting. Do you still have a good vacuum signal to the modulator? I have never had any problems downshifting a 400- I often downshift to second (or first if I'm going slow enough) and then pound the throttle. Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 1, 2008 Share Posted July 1, 2008 i've always manually shifted my trans and never hurt one yet. Th350 (two of them) and a 700r4 the 1st th350 was dying when I got it.. the front pump was shot.. 2nd th350 I took out and replaced with the 700 ~ you problaby don't want to manually downshift under power because it can put a lot of strain on things like sprags and and stuff... downshift, then mat it.. and you'll be ok. btw.. GM designed them to downshift manually while moving.. that's what those lower gears are for!! (read your owners manual).. it says to use lower gears when decending steep grades etc.. i don't think they expect you to come to a complete stop before selecting a lower gear.. these aren't lawnmowers! i was using L2 a LOT on that ride out to the oak hurst tea room.. but then I wasn't using the brakes at all on the way down those hills :> Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 1, 2008 Share Posted July 1, 2008 i am going to have the 'safetys' removed my 700r4 because it won't let me downshift into lower gears when I want to.. (mine is built to handle it) I can get to about 40mph in 1st gear, but the trans forces me down to about 20mph before I can use it.. that is a pain on the street. so basicly I can't even get an automatic downshift when my engine would let me... 6000 rpm in 1st gear is 44mph, but that's assuming no converter slip too. Quote Link to comment Share on other sites More sharing options...
Monteman1971 Posted July 1, 2008 Author Share Posted July 1, 2008 Thanks guys. I'll check the vacuum tonight and I've ordered a new module as well. The one I put in before was a "fram" and I really don't have any confidence in their stuff anymore. The governer thing will be my next move if this doesn't work. Steve Quote Link to comment Share on other sites More sharing options...
Heckeng Posted July 2, 2008 Share Posted July 2, 2008 Good thread from Chevelle forum on trannys, including downshifting etc. Transmission Thread I have blown up a sprag by downshifting unfortunately, then after doing some research I found this link. Read through the posts, there are a couple very good ones. In particular, look at #19 by Jakeshoe. I assume that he knows his stuff because of the detail he goes into, but I can't say for sure as I'm not nearly as kowledgable on trannys. Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted July 2, 2008 Share Posted July 2, 2008 good stuff, I need to finish it Quote Link to comment Share on other sites More sharing options...
wallaby Posted July 3, 2008 Share Posted July 3, 2008 Don't forget to check that the kickdown switch isn't telling the trans you have the throttle down.. Quote Link to comment Share on other sites More sharing options...
Monteman1971 Posted July 26, 2008 Author Share Posted July 26, 2008 Ended up getting the transmission rebuilt street/strip. The main drive drum was scored pretty bad and the sprags were also broken....it was ugly in there....lol. Now it's real strong Steve Quote Link to comment Share on other sites More sharing options...
Monteman1971 Posted July 28, 2008 Author Share Posted July 28, 2008 Al's dying to go.....With my upgrade in headers and exhaust as well as the transmission, I'm hoping for a couple of more tenths. I wish we had a track here on the Island.....I'd already have gone....... Steve Quote Link to comment Share on other sites More sharing options...
Sam (Bones) Posted July 28, 2008 Share Posted July 28, 2008 I wanna play too too bad we're so far apart Quote Link to comment Share on other sites More sharing options...
Cali Z28 Posted July 29, 2008 Share Posted July 29, 2008 Isn't that what the LIE is for? That road is a disaster from all the trucks.....that's what the Ocean Parkway is for Quote Link to comment Share on other sites More sharing options...
kc8oye Posted July 29, 2008 Share Posted July 29, 2008 i'm itching to get to the track too.. and see what I break first with my slicks :> Quote Link to comment Share on other sites More sharing options...
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