700R4 Tranny down shifting harsh??
04-09-2012, 04:16 AM
#1
Melting Slicks
Thread Starter
700R4 Tranny down shifting harsh??
The lockup in my 82 original 700r4 tranny was not engaging so I took it to the tranny shop and they told me it needed a $2500 rebuild. BS to that! Other than the lockup no other problems so I replaced the lockup solenoid and the TCC solenoid along with a new filter and fluid. The tranny guy did adjust the TV cable but I have not touched anything else. Now as I'm slowing down and it downshifts to first it's harsh and acts as yourself downshifted it. Anyone have any ideas why??
04-09-2012, 08:26 AM
#2
Team Owner
He has adjusted the TV cable wrong. Setting that cable properly is crucial to you getting good quality shifts (for the amount of throttle that you are applying) and, that cable should be almost fully extended when you are at a WOT condition.
From your description, the mechanic has excessive TV cable extension throughout the range of travel. That will cause harsh shifts at lower throttle settings.
Note: Because that shop could not do the job properly the first time, it may not be a good idea to return it there. You could call the shop manager and discuss it with him/her to request a more knowledgable mechanic to re-adjust it....but that may or may not prove to be any better. The worst condition you can have with that cable is to have it 'under-extended'. That condition will lead to slipping and, eventually, failed clutches from WOT use and low clutch apply pressures. After discussing with the shop manager, you need to be the judge as to how much confidence you have that a re-adjustment by that shop will be successful.
P.S. The TV cable has little to do with the lockup clutch. The engine management system computer makes the decision as to when the lockup clutch should be ON or OFF. The throttle position sensor (TPS) is more important to the function of the lockup clutch than is the TV cable.
From your description, the mechanic has excessive TV cable extension throughout the range of travel. That will cause harsh shifts at lower throttle settings.
Note: Because that shop could not do the job properly the first time, it may not be a good idea to return it there. You could call the shop manager and discuss it with him/her to request a more knowledgable mechanic to re-adjust it....but that may or may not prove to be any better. The worst condition you can have with that cable is to have it 'under-extended'. That condition will lead to slipping and, eventually, failed clutches from WOT use and low clutch apply pressures. After discussing with the shop manager, you need to be the judge as to how much confidence you have that a re-adjustment by that shop will be successful.
P.S. The TV cable has little to do with the lockup clutch. The engine management system computer makes the decision as to when the lockup clutch should be ON or OFF. The throttle position sensor (TPS) is more important to the function of the lockup clutch than is the TV cable.
Last edited by 7T1vette; 04-09-2012 at 08:30 AM.
04-09-2012, 11:16 AM
#3
Race Director
go to the BTO web site they have instrucitons on setting up the 700r4TV cable, this has to be done correctly or it will ruin the trans
www.700r4.com
www.700r4.com
04-09-2012, 05:28 PM
#4
Team Owner
Actually, the BTO website info is only good for those who are using the cable and hardware like BTO provides.
The only sure way to set the TV adjustment correctly, for all vehicles, is to tap into the TV pressure port on the left side of the the tranny. Put a fitting in the port, connect a 6 to 8' long pressure hose to it and put a 300 psi gage on the other end. Now, you can see what TV pressure does as you pull the cable in and out.
What you want to accomplish is to have proper pressures at the start point (idle throttle cable position) and the end point (full throttle cable setting) of the carb linkage movement. But, the first 1/4" or so of TV cable movement usually makes no change in TV pressure. So, you pull the cable out while watching the gage and note when the TV pressure just starts to increase. This is where the cable should be positioned at the idle setting on the throttle cable/carb linkage. Then you need to pull the cable out until the TV pressure reaches maximum. That point is where the cable should be when the throttle cable/carb linkage is at wide open throttle (WOT). If you get those two points set properly, then verify good pressures at those points when operating the floor accelerator pedal, your TV cable will be properly set.
NAPA and some other 'full service' auto parts stores can make up a pressure hose with #4 AN fittings and also provide a fitting for the gage end and the tranny end (#4 AN to 90* elbow to pipe thread). I can't remember what size the pipe fitting is, but you can just remove the plug in the tranny and take that with you to the store to match up for the fitting.
Harbor Freight, Northern Tool, and Tractor Supply all sell inexpensive 300 psi gages. The whole thing will cost about $30. It's a good investment to make certain that your new tranny doesn't throw craps in a few weeks/months.
The only sure way to set the TV adjustment correctly, for all vehicles, is to tap into the TV pressure port on the left side of the the tranny. Put a fitting in the port, connect a 6 to 8' long pressure hose to it and put a 300 psi gage on the other end. Now, you can see what TV pressure does as you pull the cable in and out.
What you want to accomplish is to have proper pressures at the start point (idle throttle cable position) and the end point (full throttle cable setting) of the carb linkage movement. But, the first 1/4" or so of TV cable movement usually makes no change in TV pressure. So, you pull the cable out while watching the gage and note when the TV pressure just starts to increase. This is where the cable should be positioned at the idle setting on the throttle cable/carb linkage. Then you need to pull the cable out until the TV pressure reaches maximum. That point is where the cable should be when the throttle cable/carb linkage is at wide open throttle (WOT). If you get those two points set properly, then verify good pressures at those points when operating the floor accelerator pedal, your TV cable will be properly set.
NAPA and some other 'full service' auto parts stores can make up a pressure hose with #4 AN fittings and also provide a fitting for the gage end and the tranny end (#4 AN to 90* elbow to pipe thread). I can't remember what size the pipe fitting is, but you can just remove the plug in the tranny and take that with you to the store to match up for the fitting.
Harbor Freight, Northern Tool, and Tractor Supply all sell inexpensive 300 psi gages. The whole thing will cost about $30. It's a good investment to make certain that your new tranny doesn't throw craps in a few weeks/months.
04-09-2012, 08:09 PM
#5
Melting Slicks
Thread Starter
Actually, the BTO website info is only good for those who are using the cable and hardware like BTO provides.
The only sure way to set the TV adjustment correctly, for all vehicles, is to tap into the TV pressure port on the left side of the the tranny. Put a fitting in the port, connect a 6 to 8' long pressure hose to it and put a 300 psi gage on the other end. Now, you can see what TV pressure does as you pull the cable in and out.
What you want to accomplish is to have proper pressures at the start point (idle throttle cable position) and the end point (full throttle cable setting) of the carb linkage movement. But, the first 1/4" or so of TV cable movement usually makes no change in TV pressure. So, you pull the cable out while watching the gage and note when the TV pressure just starts to increase. This is where the cable should be positioned at the idle setting on the throttle cable/carb linkage. Then you need to pull the cable out until the TV pressure reaches maximum. That point is where the cable should be when the throttle cable/carb linkage is at wide open throttle (WOT). If you get those two points set properly, then verify good pressures at those points when operating the floor accelerator pedal, your TV cable will be properly set.
NAPA and some other 'full service' auto parts stores can make up a pressure hose with #4 AN fittings and also provide a fitting for the gage end and the tranny end (#4 AN to 90* elbow to pipe thread). I can't remember what size the pipe fitting is, but you can just remove the plug in the tranny and take that with you to the store to match up for the fitting.
Harbor Freight, Northern Tool, and Tractor Supply all sell inexpensive 300 psi gages. The whole thing will cost about $30. It's a good investment to make certain that your new tranny doesn't throw craps in a few weeks/months.
The only sure way to set the TV adjustment correctly, for all vehicles, is to tap into the TV pressure port on the left side of the the tranny. Put a fitting in the port, connect a 6 to 8' long pressure hose to it and put a 300 psi gage on the other end. Now, you can see what TV pressure does as you pull the cable in and out.
What you want to accomplish is to have proper pressures at the start point (idle throttle cable position) and the end point (full throttle cable setting) of the carb linkage movement. But, the first 1/4" or so of TV cable movement usually makes no change in TV pressure. So, you pull the cable out while watching the gage and note when the TV pressure just starts to increase. This is where the cable should be positioned at the idle setting on the throttle cable/carb linkage. Then you need to pull the cable out until the TV pressure reaches maximum. That point is where the cable should be when the throttle cable/carb linkage is at wide open throttle (WOT). If you get those two points set properly, then verify good pressures at those points when operating the floor accelerator pedal, your TV cable will be properly set.
NAPA and some other 'full service' auto parts stores can make up a pressure hose with #4 AN fittings and also provide a fitting for the gage end and the tranny end (#4 AN to 90* elbow to pipe thread). I can't remember what size the pipe fitting is, but you can just remove the plug in the tranny and take that with you to the store to match up for the fitting.
Harbor Freight, Northern Tool, and Tractor Supply all sell inexpensive 300 psi gages. The whole thing will cost about $30. It's a good investment to make certain that your new tranny doesn't throw craps in a few weeks/months.
04-09-2012, 10:28 PM
#6
Race Director
I am running the BTO setup and it did work for me. that pressure gauge is a PITA to unscrew....
no it doesnt sound right......the car would stall if the lock up is never released
no it doesnt sound right......the car would stall if the lock up is never released
Last edited by bobs77vet; 04-09-2012 at 10:31 PM.
04-10-2012, 12:30 AM
#7
Melting Slicks
Thread Starter
Well should I go through the trouble and drop the pan to remove that extra ground wire or leave it??
04-10-2012, 01:54 AM
#8
Team Owner
I would hesitate to advise you, since my understanding of what your shop has done and what you have done is limited by just what is in this thread. I wouldn't place much confidence in any advice given under those circumstances.
