Help 700R4
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Help 700R4
Just bought my fourteenth vette.It's an 82 (my third)I always liked 82's'.There the most refined,and at my age that fit's me well.It's got 50k miles and is all original.Got it from a really cool guy that has like 25 classic cars including 6 vintage vettes.Any all is good but the 700r4 will not lock up in any gear.I put a temp switch between pin a and pin f on the obd port and can control the lockup that way but how do I get the car to do it automaticly.Also I set the tv cable as per instructions (push the rod? in all the way and step on the gas wot the adjusting rod comes out but the I get delayed shifts.If I start out slow 1-2 shift happens at 2200 rpm.That may not sound to high but when your moving in moderate traffic the engine sort of jus revs then jumps into second sort of late-but its not slipping.If I pull the rod out slowly the shift points come down but to much adjustment and the car wont downshift properly.Is it bad to use the manual shift lockup switch,and is it bad to play with the tv cable (to adjust it to my taste as opposed to the by the book way)I had 2 other 82's and both blew the trannys at low milage and I drive very very mellow.Was told by many 82 700r4 were just weak.Please any suggestions
Team Owner
Joined: Jun 2001
Posts: 43,136
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From: Thomson Georgia
I wonder why people say that your year model vette equates to a weak 700R4? I did not know that the strength of the tranny was gauged to the model or power of a vehicle.
I am thinking that there is a way of adjusting the tranny to work in synch with your car.
I am thinking that there is a way of adjusting the tranny to work in synch with your car.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
If the shifts at low throttle are happening at 2200 rpm, then the TV cable is NOT set up properly OR there are other 'things' afoot with the valve body in that tranny. Your first course of action should be to drop the oil pan and look for any metallic particles (or pieces) in the oil/pan. Also, check to see if the oil smells burnt. If no burnt oil smell and no metallic particles, put in new filter. Also, while pan is down, check out the TV cable linkage/mechanism to make sure the cable movement is getting translated to the valve properly. Another common problem with the first years of the 700R4 is that the TV valve gets stuck in its bore and causes very late shifts. There is a repair kit available for that for about $50, which includes a non-stick valve, springs and other small hardware. It requires dropping the valve body to change the valve, but it's not a big job.
My money is on the TV cable issue and/or a stuck TV valve.
P.S. Put a drain plug in that pan when you get done....just in case you need to drop it again. NAPA sells a 'bolt-in' drain for about $5 or so.
My money is on the TV cable issue and/or a stuck TV valve.
P.S. Put a drain plug in that pan when you get done....just in case you need to drop it again. NAPA sells a 'bolt-in' drain for about $5 or so.
Last edited by 7T1vette; Apr 12, 2012 at 09:14 PM.
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Joined: Sep 2004
Posts: 11,874
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
and yes setting the TV cable up wrong can cause damage....you mentioned it wouldnt lock up i wonder if one of the solenoids is bad or the either the power or ground wire is broken. my 700r4 actually had a 3 and 4th lock up solenoid, i am not sure what yours has. i dont see any issues with loking it up manually as long as you remember to unlock it....i suppose you could hook up a brake light relay so that when you step on the brake it unlocks. it makes more sense to me just to get working like it was designed though
Last edited by bobs77vet; Apr 12, 2012 at 10:36 PM.
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
In the middle of '87 GM updated the 700 trannies quite a bit, there is basically no way to make a earlier 700 go with the later specs.....
so change out the entire unit for a later core, and rebuild with a TRANS GO shift it....no other.....
the lockup failure can be caused from anything like the Oring on the input shaft through converter, to TCC solenoid/valve inside pan, to gunk in the front pump valves, and sticking valves due to scoring...
failure to lock up of course can also be electrical such as no +12 to the tranny, that can be because the brake switch is bad OR maybe a control relay....if you have +12 at the red tranny wire, the other side should be ground to affect lockup....if it is, and you still have no lockup,...it's the mechanicals above....
how do I know this? I rebuilt a 700 for my motor home, and had lockup troubles....too boot I have lockup problems on the 200 in the vette, so getting ready to drop that also....maybe next week...
so change out the entire unit for a later core, and rebuild with a TRANS GO shift it....no other.....
the lockup failure can be caused from anything like the Oring on the input shaft through converter, to TCC solenoid/valve inside pan, to gunk in the front pump valves, and sticking valves due to scoring...
failure to lock up of course can also be electrical such as no +12 to the tranny, that can be because the brake switch is bad OR maybe a control relay....if you have +12 at the red tranny wire, the other side should be ground to affect lockup....if it is, and you still have no lockup,...it's the mechanicals above....
how do I know this? I rebuilt a 700 for my motor home, and had lockup troubles....too boot I have lockup problems on the 200 in the vette, so getting ready to drop that also....maybe next week...
Team Owner
Joined: Jan 2006
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From: Crossville TN
Direct wiring of 12v through a switch and then to the lockup clutch is one sure way of [eventually] trashing the lockup clutch. When that setup is used, it is almost impossible to remember to flip the switch OFF when an 'unusual' or 'emergency' situation occurs. That lockup clutch was never meant to carry much load. That's why the factory control program causes it to drop lockup whenever the throttle is significantly increased or the brakes are engaged.
The intent of the lockup clutch is to eliminate the losses through the torque converter when the car is at a steady-state speed and with normal loading.
When one forgets to switch off that lockup clutch a few times, it takes its toll on the hardware.
The intent of the lockup clutch is to eliminate the losses through the torque converter when the car is at a steady-state speed and with normal loading.
When one forgets to switch off that lockup clutch a few times, it takes its toll on the hardware.
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Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
thats interesting i thought when i was locked up in 4th gear that it didnt unlock when i stomped on it. (i have the std BTO set up) does the TV cable going to WOT somehow sent a signal to unlock the Torque Converter?
