mikeringland Posted March 12, 2021 Share Posted March 12, 2021 Hey guys, So I swapped out the 350 in my 72 for a 454. It runs great, but...it's not shifting into third gear. It has a TH350, worked perfectly fine before. I have a suspicion its the transmission kick down cable. I attached a photo of it installed. It is the one from when the 350 was in there. It appears to be long enough, but, should have I replaced it with the longer one? The transmission itself seems fine. The hard vacuum line from the trans is connected to the vacuum port on the top of the intake. What do you guys think? Mike Quote Link to comment Share on other sites More sharing options...
72-CLASSIC_RIDE Posted March 12, 2021 Share Posted March 12, 2021 The cable where it attaches to your transmission may be the culprit depending on the Bracket on the tranny. There is a difference between the 350 and 454BB bracket. I modified my 350 bracket to work with 402 BB when I upgraded to the BB. Just a thought...................... Doug Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted March 12, 2021 Share Posted March 12, 2021 The cable has NOTHING to do with the transmission shifting into 3rd gear. You can disconnect it and drive years without issues and it will still shift into all gears. The cable is for the "kick down/passing gear" mode. Check to make sure you have vacuum going to the modulator and that it is sufficient. Start there. Quote Link to comment Share on other sites More sharing options...
Mike Brichta Posted March 12, 2021 Share Posted March 12, 2021 It sounds like there are two different cables being talked about above. One is the th350 detent cable and the other is the console cable. Does the car have a console? Am I mistaken? Mike Quote Link to comment Share on other sites More sharing options...
mikeringland Posted March 12, 2021 Author Share Posted March 12, 2021 No console Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted March 12, 2021 Share Posted March 12, 2021 The other cable is for a 700r4 or 200r4. Those overdrive transmissions need the tv cable to be adjusted correctly or the trans will internally burn up. Cook the clutches. Tv- throttle valve. It controls the shifting of the trans. This is not the case with the th350. Quote Link to comment Share on other sites More sharing options...
Dtret Posted March 13, 2021 Share Posted March 13, 2021 Proper vacuum to modulator. I agree not a cable issue. For that anyway Quote Link to comment Share on other sites More sharing options...
cny first gen 71 Posted March 13, 2021 Share Posted March 13, 2021 If it was a vacuum issue you wouldn't have a 1 to 2 upshift either would you. I know mine didnt when the vacuum hose cracked. I had to manually shift it to get to upshift. Possibly the cable may need to be moved if the cable is pulled slightly maybe it thinks it's under load. Not sure just throwing that out there. Quote Link to comment Share on other sites More sharing options...
MC1of80 Posted March 13, 2021 Share Posted March 13, 2021 The governor will have it shift 1-2. Why no 2-3? Let's see what he says and finds. Quote Link to comment Share on other sites More sharing options...
wallaby Posted March 13, 2021 Share Posted March 13, 2021 There is an adjustment that can be made to the cable installed length. It is made at the plastic connector at the carburetor bracket. I don't remember how it's done...a simple push on a tab while holding the throttle fully open, I believe. And FYI, the trans will shift through all gears even without the vacuum modulator hooked up. In that situation, the modulator sees zero vacuum....just as it would if the engine was at full throttle. The upshifts would then depend on the governor, an probably occur at around 5000 rpm. You would have to have a long stretch of road to get it into 3rd... The kickdown cable might be too tight and the trans is trying to step back a gear, even at part throttle. (again, the governor will force an upshift if engine revs get too high). Does your 1-2 shift seem to happen at a normal time? Or is it hanging on to first gear for a long time? Quote Link to comment Share on other sites More sharing options...
mikeringland Posted March 13, 2021 Author Share Posted March 13, 2021 It was the kickdown cable. Due to the location of the bracket on the 454, the cable is under a load when it is simply connected to the carburetor. I disconnected it and it shifts perfectly fine. Basically when I was accelerating, the transmission was trying to downshift, rather than upshift since the cable had tension on it already. I just have to determine how to change the slack on it now to be able to reconnect it. Thanks for the help everyone, Mike 1 Quote Link to comment Share on other sites More sharing options...
wallaby Posted March 14, 2021 Share Posted March 14, 2021 2 Quote Link to comment Share on other sites More sharing options...
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