700r4 lockup switch??

jaggede · January 21, 2007, 10:55:44 PM

i installed a 1985 700r4 with the new process transfer case in my 1976 shorty and i didnt know that the wires coming out of the side of the tranny were for a lock up switch. (a friend said it was for a neutral saftey switch) anyways... i drove it for probably 2000 mile with out the switch wired and now the tranny is shifting late 2nd gear around 35mph 3rd around 45 50 mph etc also any chance the TV cable could have all of a sudden gone out of wack?? anyone know anything about these trannys?? How imporant was/is the lock up ?? thanks

old yeller · January 22, 2007, 11:26:59 PM

The lock-up function shouldn't have any effect on shifting. The convertor generates more heat when running unlocked. Heat is an automatic's enemy. I know guys who have run 700-r4's without lock-up function for a long time in street rods. Better check your TPC for proper adjustment.

old yeller · January 22, 2007, 11:27:40 PM

The lock-up function shouldn't have any effect on shifting. The convertor generates more heat when running unlocked. Heat is an automatic's enemy. I know guys who have run 700-r4's without lock-up function for a long time in street rods. Better check your TVC for proper adjustment.

1FATGMC · January 22, 2007, 11:41:33 PM

Quote from: "jaggede"i installed a 1985 700r4 with the new process transfer case in my 1976 shorty and i didnt know that the wires coming out of the side of the tranny were for a lock up switch. (a friend said it was for a neutral saftey switch) anyways... i drove it for probably 2000 mile with out the switch wired and now the tranny is shifting late 2nd gear around 35mph 3rd around 45 50 mph etc also any chance the TV cable could have all of a sudden gone out of wack?? anyone know anything about these trannys?? How imporant was/is the lock up ?? thanks

Like the others said it isn't going to effect the shifting. How did you set-up the TV cable. Look ( HERE ) and tell me if you got the geometry correct on the bell-crank and the rest of the linkage correct. If not that could be why it is failing now. These are not that hard to do correctly, but not forgiving if you don't.

c ya,

Sum

jaggede · January 23, 2007, 10:20:43 AM

thanks guys. i adjusted the cable and still no effect. the cable felt like it was pulling inside the tyranny. but i said the hell with it and bought a new cable and installed and presto all better!!!! i will return to the donor truck and grab the lock up stuff off it. Another question......i never had much luck servicing a tranny ie changing the fluid... it seems whenever i change the fluid the tranny fails shortly afterward... would like to service my tranny but dont want any more problems

1FATGMC · January 23, 2007, 01:00:35 PM

Quote from: "jaggede"thanks guys..........Another question....
..i never had much luck servicing a tranny ie changing the fluid... it seems whenever i change the fluid the tranny fails shortly afterward... would like to service my tranny but dont want any more problems

I don't know what to tell you there. We bought a '78 buick with a 305 sbc in it a couple years ago and I was taking it to Missouri. I had no idea if the transmission had ever been serviced, so I changed the fluid. Now this was just the fluid in the pan and not what was in the converter. Took off a couple days later and the transmission went from good to bad in about 700 miles and blew up in eastern OK. Thankfully Hooley and WZJUNK bailed me out of that mess. Hooley gave me a 200R4, that got new fluid and it has worked fine ever since with a lot of miles.

I service my 700R4 every 20,000-30,000 miles or so, but I drain the pan, fill it and then pull a cooler line off and pump the old stuff out of the converter. When it gets to the new stuff I reconnect the line and then fill to the fill mark.

c ya,

Sum

Dave · January 23, 2007, 02:00:14 PM

The problem with changing the fluid in a hi milage tranny is after you get the new stuff in there it tends to clean up the stuff and open the tolerences that were filled by crud. Then you get slippage and in the end a tranny that dont work. I remember dumping the water out of an old turbo 350 and putting it in and heading to colombus to the nats one year! Got me home and then i had to back it to the garage

Dave

1FATGMC · January 23, 2007, 02:56:49 PM

Quote from: "jusjunk"The problem........Then you get slippage and in the end a tranny that dont work. .
Dave

I wished mine would have slipped. It was harder and harder to get it to shift from 2nd to 3rd. Finally it wouldn't shift into 3rd at all and after running about 50 or so in 2nd for a few miles it grenaded. The smoke trail was pretty impressive. John or someone said it looked like when one of the cup cars blows up good. If it would have shifted to 3rd just one more time I probably would have made it to Hooley's house as I had just gone thru the turnpike toll booth and from there I could have stayed in 3rd almost all the way to his place.

I think in my case some of the crud got loosened and got stuck in a valve body passage. But that is something only Tony would probably know

.

c ya,

Sum

Dave · January 23, 2007, 04:48:20 PM

I lost th4 front seal on the 34 one year going to knoxville got er fixed car was covered with trans fluid so we decided to just head home. First gas stop and it wouldnt back up. I went all the way back to kentucky 2 weeks later to get it fixed by the guy and (they call me lucky ya know) hosed me for more money! Never again i take my car and it better be fixed.

I still dont know what made me pay the prick? Needless to say for kicks i tried his number a couple months after i got home and it was disconnected. Funny part now thinnin back he told me he was from Texas

Dave

jaggede · January 23, 2007, 09:29:08 PM

so its a crap shoot on wheither or not to change the fluid. what if i change it over time i could put an oil sucker (for like changing the oil on a boat-u suck the oil out the dip-stick tube) i could suck out a couple quarts and replace it here and there until it clear up?? what do u think of tranny shops?? i dont know the guy but i was going to bring it and have it looked at before i changed the TV cable and i still have the appointment. i ask him on the phone if he would do a pressure check on it and he say that they just drive it and can tell whats going on.... the tranny oil isnt black but it isnt brand new either