I’ve got a 700r4 with a Lokar shifter & Chevy 261 that lossed drive after an hour run. If left for a period it would pull again then stop again after a short period When I say lossed drive I mean I could engage all gears but it will not pull in any I bought the box as good used from someone I trust I’ve just changed the fluid and filled it to the correct levels at hot & cold with Dextron 3 and have changed the internal filter These are the psi pressures I’m getting at tick over with foot on brake P- 70 R- 110 N- 70 OD- 70 D- 70 2- 140 1- 170 If I pull the TV cable while at tick over I’m getting 150 Do these sound about right before I go out for a drive and risk getting stranded again Sent from my iPhone using H.A.M.B.
Yes all hooked up, adjusted so the slide is all the way in on idle then it self adjusts when you press the gas peddle fully down What pressures would you expect to be seeing? Sent from my iPhone using H.A.M.B.
Will this help?https://www.tciauto.com/trans-line-pressure or These readings can be obtained by attaching a 300 psi fluid pressue gauge to the appropriate pressure port on the transmission, and running the engine at 2000 rpm, and are a valuable source of information when troubleshooting transmission problems or as a system check after rebuilding a transmission. Range Minimum Maximum Park 90-110 190-230 Reverse 95-120 200-300 Neutral 90-110 190-230 Overdrive 90-110 190-230 Drive 90-110 190-230 Second 185-230 185-230 Low 185-230 185-230
I found a chart of pressures 700r4 and 4l60 are the same (not to be confused with 4l60e). https://www.jalopyjournal.com/forum...-there-have-low-pressure-at-idle-rpms.931122/ *edit someone was faster than me ^
The tv cable needs to be adjusted to be fully extended when the throttle is wide open. The geometry of the throttle lever on your carb needs to be correct before you work on anything else. This might help http://67-72chevytrucks.com/vboard/showthread.php?t=400031
There’s more to the TV cable than that. Depending on what you have it connected to, you may need a geometry correction kit to achieve the correct TV cable adjustment. Sent from my iPad using The H.A.M.B. mobile app
Driving a 700R4 with an improperly adjusted cable can spell demise pretty quickly! And they aren't just pulled fully out, and self adjusting either. There are numerous Youtube videos about how to properly adjust a 700r4 cable that should be watched before you even pull out of the driveway. Most suggest you drive the car and adjust the 1st-2nd shift point between 20-25 mph. Just take it on a drive, and if it doesn't immediately shift within that mph range, stop and reset it. Pull more cable out to raise the shift point, or release it to shorten it if it shifts higher. Took me a few blocks to keep stopping and adjusting, until it was perfect. And as mentioned the lower carb arm needs to be very specific length from the pivot shaft for the 700R4, so make sure the measurement and attachment point is exact.
Ok thanks for all the info everyone, I will take some measurements tomorrow and see what I’ve got Sent from my iPhone using H.A.M.B.
Here’s a video of the TV and carb linkage https://photos.app.goo.gl/ATiXjxVXjxv3isCG8 Sent from my iPhone using H.A.M.B.
Are you saying it doesn’t move? That’s how I understand the post. Doubt it’s tv cable adjustment if it doesn’t move. Sent from my iPhone using H.A.M.B.
It’s drove fine for about an hour then lost drive in all gears I’ve found the fluid coolant lines were leaking so I’m hoping it was just low on fluid but I wanted to check that my pressures were about right before I tried to take it out again Sent from my iPhone using H.A.M.B.
Not sure I'm seeing this correctly, but it looks like it might be backwards, and the wrong throw length also? This might help: SUBJECT: Proper installation of the throttle valve cable on after-market carburetors or fuel injections. This information applies to all 700R4, 4L60 and 200-4R transmissions. Throttle valve cable adjustment instructions, numbers 4, 5 and 6. #1. The button that the cable hooks to at the carburetor or throttle body must have a 1 and 3/32-inch radius from the center of the throttle shaft to the center of the button the cable hooks to. #2. Looking at the throttle shaft lever from the left side at idle position, 33% of the throttle lever total travel must be to the rear of the throttle shaft centerline. And at wide-open throttle, 67% to the front of the throttle shaft centerline. This will be about ½-inch to the rear and 1 inch to the front of the throttle shaft centerline. #3. The throttle valve cable must be hooked up in this manner so the pressure will rise faster off idle and slow down at heavy throttle. If the pressure cable is pulled in a more even manner the pressure will be too low at light throttle. Failure to hook-up the throttle cable in this way will burn the three-four clutch pack up fast. #4. The throttle valve cable controls transmission pressure. Adjusting this cable is the most important step when installing a 700R4, 4L60 or 200-4R transmission. #5. The final step is to adjust the throttle valve cable. The cable must be adjusted so it is pulled fully out at wide-open throttle. To make sure disconnect the cable, hold the throttle wide open with your left hand, pull the cable fully out with your right hand and see if the cable end lines up with the button on the throttle lever. The cable should also be pulled out 3/8 to 1/2 of an inch at idle. #6. Do not attempt to adjust the shift timing with the throttle valve cable. The shift timing is controlled by the governor springs. For higher shift points at wide-open throttle, install lighter springs or remove one of the springs. For lower shift points at wide-open throttle, install stronger springs.
Gotcha. Don’t think I saw the low fluid part. That’s probably why it didn’t move. Sent from my iPhone using H.A.M.B.
Low fluid pressures is why it didn't move. Fill it up and recheck but if still that low you probably have burnt something up either because the TV cable was hooked up in correctly, you ran it out of fluid or it was not put together correctly.
When I say it was low on fluid I mean the coolant lines were weeping and the fluid level was just above the bottom hatched level I’m going to take some measurements of the TV cable setup tomorrow and also attempt to run it up and down the road and record what the shift / mph speeds are Sent from my iPhone using H.A.M.B.
Managed to get good pressure today after the fluid and filter change If the TV cable was adjusted to achieve a gear change between 1 & 2 at 20mph the next shift seemed far to high so I’m thinking the bracket is probably wrong Next job is to fully measure the setup against the drawings Sent from my iPhone using H.A.M.B.
Well looking at the drawing and info you’ve all posted it looks like the person who made the bracket made it completely wrong Please let me know if I’m reading this correctly The radius needs to be 1” 3/32 and mine is 1” The TV cable at Idle needs to be 1/2” behind the centre line and full throttle 1” in front, mine is nothing like that Sent from my iPhone using H.A.M.B.
I'd see if I could get a longer cable and hook it to the carburetor. ca1980 is a part number for a long adjustable one.
I'd simply make an adapter arm to bolt or weld to your linkage so it positions the attachment point at the correct spot, and the correct length from the pivot point. The length of the cable is adjustable I'd guess, if they used the stock 700R4 bracket on the end of the cable. So once you've got an arm mounted at the correct position and length, it just requires you to adjust the fixed mount until it shifts at the correct point.
As I see it you couldn't be more wrong! The schematic refers to the carb bracket, but you're looking at and taking measurements off of the transmission end, if my eyesight serves me correctly!!! I doubt the trans end of the linkage has been messed with. The carb end is where the correct bracketry needs to be and becomes an issue when a 700r4 is installed somewhere where one previously did not reside. Hope this makes sense and helps! Chris
No my images are off the carb bracket, your right the Trans end is all ok https://photos.app.goo.gl/ATiXjxVXjxv3isCG8 Sent from my iPhone using H.A.M.B.
You're right! Apologies! I was looking for a four barrel carb and saw what I though was the transmission, without seeing it wasn't a 700r4 despite my having one! My bad. Post #27 makes sense as the solution. Using the schematic 78 degrees of throttle shaft rotation seems to be the measure - logically it would be 90 degrees as an absolute maximum, so 78 sounds logical. Might be worth checking what you have as your pics look nothing like that amount of rotation - I wonder how that works! You'd need a longer radius to achieve the same length of pull over a reduced throttle shaft rotation. Some more info here, including lengths and angles, albeit four barrel related! This appears to put the idle position nearer to the throttle shaft centerline and the wot further from the shaft centerline. https://www.stevesnovasite.com/threads/700r4-holley-dp-bracket.661083/ Chris
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