1970MonteMotion Posted January 19, 2012 Share Posted January 19, 2012 The last issue with my monte sounded like my carb or my passing gear. When I stomp the gas, the car moves, but it doesn't make that big down shift rumble. It sounds or drives as if the back two barrels on the carb aren't opening up. I had a guy check, and he says they are, so scratch that. The only other thing I could think of was the passing gear cable. It looks to be functioning when you manually push throttle by carb, but it looks a lil loose. My dad tried adjusting it, but no luck. I am hoping a new cable could fix this, as I am eager to get to the motor/tranny/paint/body. My dad said it could be the modular valve, and another guy said it could be the vacuum on the down shift cable. Any pointers, tips, or help? Also, apologies if this was suppose to go in another section Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 I see this should have maybe been placed in the drivetrain section, so apologies. If the "detent" cable is the same as the "passing gear", "kick down cable", or throttle cable which runs to tranny, I may know where my problem is coming from. I noticed a small leak where the cable runs into the tranny. Maybe if it has o-ring and plastic piece, replace them, and the cable. Could this leak be an indicator that the cable is bad? Quote Link to comment Share on other sites More sharing options...
montefrazer Posted January 19, 2012 Share Posted January 19, 2012 I'll assume this is a Turbo 350 since it has a cable. It is a kick down cable but also called by other names. It just shifts the tranny a lower gear at wide open throttle. The cable has a Z at the end that hooks into the part coming from the tranny you think is leaking. This is hard to work on with the tranny in the car. Do you have any floor mats or thick replacement carpet that stops the gas pedal from moving through it's full travel? Take out any floor mats and go for a ride. Floor the gas pedal in drive when you're going around 40 MPH. Then shift to second gear and see if there's any suddon change with higher RPM and speed. If you get a big change in RPM and speed, it's a tranny or linkage problem. If not, it's an engine or carb problem. Good luck. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 No carpet or carboard I can see hendering pedal. I will try what you are asking to see help determine the problem. I want to say if I'm at 40, and shift to 2cnd, she may spin the tires...lol. The car will move when you stomp it from a stand still. I know it will boogey in 2cnd at 40mph, then WOT. However, it's a mono toned sluggish sounding roar, and you never get that High pitch howl the 350/300hp sbc is known for. It doesn't Holler. Imagine these two senarios. 2 perfectly fine automobiles, engine and tranny wise. From stand still, WOT in.. 2007 Z06 CORVETTE - tires smoking, high rev sound, take off 1977 C20 VAN- Tires may squeel, low sound on take off, more a sluggish take off. I know my car can be the the Vett Quote Link to comment Share on other sites More sharing options...
black07ss Posted January 19, 2012 Share Posted January 19, 2012 Not to second guess you but did you adjust it right? There is a clip that needs to be lifted by where it is snapped into the bracket by the carb. Once it is released have someone push the accelerator to the floor, while holding it there push the clip back down. Some may have a metal piece there. Do the same pushing the accelerator all the way and hold it there, then have someone push the metal piece down Quote Link to comment Share on other sites More sharing options...
montefrazer Posted January 19, 2012 Share Posted January 19, 2012 Kick down will do nothing for you in first. In second it will down shift back into first and in third it will down shift back into second. There should be at least a 500-600 RPM difference when you get a down shift at 40 MPH. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 Tried fooling with adjusting it, and got some slop out of it, but no luck. Dad mentioned a modular valve. However I wouldn't know where to look for one at, or tell if it's bad. Another guy suggested the vacuum may be gone from the detent cable, but couldn't say what would fix this problem. Gosh I hate troubleshooting things... Can't rest until I know what it is, and when it's fixed! Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 Thanks Frazer. That is just it. You just described it, without describing it. When I stomp it in Drive, or 3rd so to speak, it does not shift back down to 2cnd. If I'm in 2cnd, it does not downshift back to 1st. It just stays in the gear it's in, and builds speed from th same gear, although it's more practical to be at a higher RPM to accelerate faster! Bingo. That being it said, is it safe to say it's still the passing gear cable? Quote Link to comment Share on other sites More sharing options...
monte70car Posted January 19, 2012 Share Posted January 19, 2012 the modular valve is on the side of the trans it will have a vacuum line coming off of it and it ties to a T on the intake. there is no vacuum on the passing gear as it based on the throttle. if the modular is bad it will suck trans fluid up to the motor and for a few bucks you can't go wrong on changing it. the main question is when did you notice the problem and during that time was anything changed. if it was a 2bbl carb on it and you changed over to a 4bbl carb you could need a cable for a 4bbl, but don't quote me on that. again on the same line with the passing cable there is a different length cable for the throttle. Quote Link to comment Share on other sites More sharing options...
black07ss Posted January 19, 2012 Share Posted January 19, 2012 If you have adjusted it correctly. The cable may have broke or is frayed in the sheath. I would take it off of the carb and pull it. If the cable pulls out it is broken. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 the modular valve is on the side of the trans it will have a vacuum line coming off of it and it ties to a T on the intake. there is no vacuum on the passing gear as it based on the throttle. if the modular is bad it will suck trans fluid up to the motor and for a few bucks you can't go wrong on changing it. the main question is when did you notice the problem and during that time was anything changed. if it was a 2bbl carb on it and you changed over to a 4bbl carb you could need a cable for a 4bbl, but don't quote me on that. again on the same line with the passing cable there is a different length cable for the throttle. Off topic, what color is your car? Is it the factory color, and do you have a vynal top? The car has done it since I had it. Wasn't driving it much, and planned to sell it, but had a change of heart. I think it's the cable, because I had a closely related problem on my old 71 MOnte. Just can't remember what fixed it, but I believe it was the cable. Could I install new cable w/o dropping tranny? Also, I'll be adding a stall soon, and will get the tranny freshened up some. Quote Link to comment Share on other sites More sharing options...
montefrazer Posted January 19, 2012 Share Posted January 19, 2012 No down shift means bad cable adjustment, connection, or intrnal tranny problem. The cable just connects to the transmission internally to make it down shift. If I remember right, it moves a valve and redirects hydraulic pressure to cause the down shift. When you grab the cable and pull it as far as it will go, you should feel some spring type pressure when you are almost at the end of the pull. This is when the down shift happens. The rest is just free play to let the carb and it's linkage work. Quote Link to comment Share on other sites More sharing options...
monte70car Posted January 19, 2012 Share Posted January 19, 2012 Robert as far as the color of my monte its a 99 GM color called copper brown 27m it was color matched to HOK rootbeer. As for a vinyl top it has an original black vinyl top off of another 70 Monte. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 Robert as far as the color of my monte its a 99 GM color called copper brown 27m it was color matched to HOK rootbeer. As for a vinyl top it has an original black vinyl top off of another 70 Monte. My 71 was awfully close in color from the factory. Had a darker brown vynal top though. I want to paint mine this color, especially if I can find the correct top color. Thanks for clarifying. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 No down shift means bad cable adjustment, connection, or intrnal tranny problem. The cable just connects to the transmission internally to make it down shift. If I remember right, it moves a valve and redirects hydraulic pressure to cause the down shift. When you grab the cable and pull it as far as it will go, you should feel some spring type pressure when you are almost at the end of the pull. This is when the down shift happens. The rest is just free play to let the carb and it's linkage work. I'll take it to a tranny specialist tomorrow. That way I'll know for sure. I have plans to add shift kit and stall converter also, so why not? Thanks for all of the tips. Quote Link to comment Share on other sites More sharing options...
montefrazer Posted January 19, 2012 Share Posted January 19, 2012 You can do it but it's a real PITA. Check out this thread http://www.nastyz28.com/forum/showthread.php?t=140403 I'd wait until the tranny is loose for the stall swap. Just manually shift it to second when you want to hear it roar until then. Quote Link to comment Share on other sites More sharing options...
1970MonteMotion Posted January 19, 2012 Author Share Posted January 19, 2012 You can do it but it's a real PITA. Check out this thread http://www.nastyz28.com/forum/showthread.php?t=140403 I'd wait until the tranny is loose for the stall swap. Just manually shift it to second when you want to hear it roar until then. Thanks again my friend. Now... to figure out which stall converter to go with... TBC Quote Link to comment Share on other sites More sharing options...
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