Shifting problems, overdrive

[DavidTX]

My 71 has a 2 barrel 350. I recently installed a 12 bolt 3.55. I had a 2004r installed and the xmsn mechanic couldn't get it to shift properly. He went back through the xmsn, replaced the valve body, and even pump. No luck so he asked if he could install a 700r4. He is still having problems getting it to shift properly and has replaced the valve body in it also. He has done numerous 700r4 conversions previously without any problem.

I assume the carb is the original 2 barrel rochester. Can anyone provide any guidance? I am sure someone has had this problem also. Thanks in advance for any suggestions.

[MonteAZBB70]

I'm certainly no tranny expert, but it sounds to me like your mechanic isn't getting the TV cable adjusted properly. These don't have a detent cable like the old TH350. They use a Throttle Valve cable to control shift points, line pressures, etc. Even the geometry of how the cable attaches to the carb can come into play. That's about all I know when it comes to OD trannies, but maybe someone else will chime in.

 

Mike

[Ian]

The only way to get a 200r4 or a 700r4 to shift right is to adjust the TV cable using a pressure guage. Check out http://bowtieoverdrives.com they have the instructions and the guage.

 

Ian

[Grease]

As MonteAZBB70 says above the throttle valve cable needs to be adjusted correctly . In your case most likely it is in the geometry of the cable connection on the carb throttle shaft. I think if you check the Bowtie overdrive site that Ian links above you will find they sell a kit for correcting this on some carbs. I feel this is the direction he needs to work on with your problem . Otherwise I'd say a XSMN mechanic who has this many problems wouldnt be in bussiness long .

[DavidTX]

Thanks guys. That link http://bowtieoverdrives.com provides a wealth of information. The only thing it doesn't show is the measurements from idle to WOT and the distance from throttle shaft to point of attachment of TV cable.

[monte70car]

should have a line pressure of 100 psi or atleast thats what i needed for my 700r4's

[alex's72fgmc]

try this first there is a adjustment clip on the cable by the carb some you push like a button others are a bit different. "with the car off and in park" have someone hold the button down and push your gas pedal to the floor and hold it there. then have the helper remove his hand from the button. then remove foot from gas pedal. this should reset you cable to where it needs to be. if that does not work then check the line pressures and adjust from there.

[alex's72fgmc]

http://www.tvmadeez.com/tvcable_instructions/universalcable.php

 

http://www.tvmadeez.com/tvcable_instructions/stockcable.php

 

http://www.tvmadeez.com/tvcable_instructions/braidedcable.php

 

pressure guage installation point for 200 4r

 

http://www.tvmadeez.com/press_gauge/index.php

[DavidTX]

I am not sure what all he did but I got the car back yesterday and it runs great. Those 3.55 gears in that 12 bolt really makes a difference. I will be ordering a crate engine putting out 400-410 HP next week. Looking forward to getting it up and running. Still have to order headers, intake, carb, etc. I already have MSD 6AL with distributor but haven't installed it due to stock 2 barrel engine installed now. I am also considering installing a serpentine belt system that I took of a GM 5.0 liter engine.