Hello guys, I think I’ve got a fun one. I have a 1963 c10 with a carbureted 350 and 700r4 trans. The issues I’m having For one it up shifts too quickly into overdrive and the TCC locks up immediately causing poor drive ability. Secondly, there is no kick down. manual downshifts only. The same applies for the TCC. No amount of throttle input will get it to unlock. Lastly, at very light throttle such as in town throttle it it’s simulates neutral after second gear. You can get it to go through all gears again if you give it wide-open throttle. If you go back to light throttle, you have first and second, then neutral and will not downshift again until you are almost at a complete stop. anything in particular you guys can .2 would be great. The throttle valve cable looks to be adjusted overly tight. I’m assuming in an attempt to fix these issues. Thank you for your time.

 

Read the procedures on how to set the TV cable correctly. That cable controls trans line pressure and is super critical. Sounds like yours isn't setup correctly. If you think it is and it still doesn't act correctly. You need to put a gauge on it so you can see the line pressures.

Locking and unlocking the TC is commanded with a switch of some sort. You need to see what is commanding your lockup. I had mine on a simple on/off switch so I could lock it manually when cruising only.

I spent a lot of time/effort/money getting a 700r4 to survive behind decent power. Its not an easy task and not a lot of trans builders are as familiar with them. With mine, it was all about the line pressures. More the better in my case. Had a decent clutch pack and shift kit in it as well, but that alone at factory pressures didn’t cut it. I was rebuilding every year… if that. You need the aftermarket boost valves to get the pressures up for the trans to last much over 400-500hp IMO. After the 4th rebuild at about $900 a pop… we finally had it holding up well in a 600ish whp 2900lb drag car.

I've since switched to Glides, and I'm never going back! lol

 

Its sounds like the throttle valve is stuck not at WOT but at some lower level. That is what I would look at first.

 

Thank you for the replies gentlemen. It looks as if the three wire plug coming out of the transmission is whittle down to just one wire going to a 12 v source. I assume that means that it is on a pressure sensor to activate TCC when overdrive or fourth gear has completed. I may have to put a manual switch inside the cab if I cannot get overdrive to shift later and downshift appropriately.. What is really bugging me is the fact that it will, not make the third gearshift when warm but drive perfectly fine for the first 20 minutes after that you have to use wide-open throttle to see a one 234 shift happen

 

Also, I just noticed that the TV cable is pulled so tight that we don’t actually have wide-open throttle. The travel is limited by the amount of cable.

 

1st and foremost take a pressure test in all ranges @ idle and with 1500-2000 rpm with the cable pulled. Then step 2 is to make sure the TV geometry is set up properly

 

Yessir will do. Thank you for the downloadable material as well. This is a huge help!

 

Preesure test and watching the sweep as you pull the TV cable will tell you alot and mentioned and let you know if the THROTTLE VALVE is sticking . Also note i have no idea what year 700r4 you are dealing with but I have found the very early VB with the aluminum sleeve throttle valve the sleeve is many times justy worn out . Also you could have something blocking the small orifice hole or holes #10 in the plate . But checking presure is first move.

 

Also you don't really want the TC locked up when "racing". I'd just disable that for now until you get the rest sorted. It should be the last step.

 

Ok so I took this transmission out and started taking the valve body apart. The tv limit valve is missing a plug I think. It just has the spring and the valve which was really cruddy and stuck. This is a 1991 valve body so I think it is supposed to have a plug in there. Is that right?

 

One end of the valve is exhausted so i dont think so but brain fart wont let me remember will look at vb when i go out to shop
https://cimg5.ibsrv.net/gimg/ls1tech...7c8672856d.jpg

 

OK so gentlemen I got the transmission reinstalled into this truck and I have many issues. First and foremost I would like to go over the pressures that were discussed earlier in the posting. In every other gear besides reverse, I have 60 psi plus or minus two or three. in reverse however The pressure rises and stabilizes at 200-210 psi. Now I did install a newer 4l60e pump into the case after following the mods layed out in the tips and tricks section. Im thinking these are valve body issues.

 

Forgot to say that These pressures stay the same no matter what is done to the tv cable. No line pressure rise at all even with increased rpm.

 

I also described the issues here a little bit.