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i know this subject has been talked about but this one is a little different so here goes. my 1984 f150 has a 625 street demon carb, 351w mildly built, 3.73 gears the AOD was just rebuilt with a TCI constant pressure VB and a 2000 B&M stall converter installed. i think that it's shifting to early because i'm in third before i hit 20mph and then it won't downshift from 3 to 2 when i floor it it will just lug along but i can manually shift it and go. my throttle cable and kick down or TV cable are by lokar. so should i increase the line pressure to correct this?? oh i get OD around 45-47 mph..
Yes I would increase the pressure or make the cable shorter. It will think you are pressing harder on the throttle and delay the shifts and increase the pressure.
i know this subject has been talked about but this one is a little different so here goes. my 1984 f150 has a 625 street demon carb, 351w mildly built, 3.73 gears the AOD was just rebuilt with a TCI constant pressure VB and a 2000 B&M stall converter installed. i think that it's shifting to early because i'm in third before i hit 20mph and then it won't downshift from 3 to 2 when i floor it it will just lug along but i can manually shift it and go. my throttle cable and kick down or TV cable are by lokar. so should i increase the line pressure to correct this?? oh i get OD around 45-47 mph..
Drive your truck while keeping the RPMs at 1500 RPM. At what speeds does the AOD shift? With 3.55 gears and the correct TV pressure, here are my shift speeds:
1-2 = 15 MPH
2-3 = 23 MPH
3-4 = 45 MPH
The lower 3.73 gears will make it shift at slightly lower speeds. If your speeds are a lot lower than those above, tighten up the TV cable. If the geometry between the carburetor and the throttle valve is correct, you want the TV cable to be at full pull when the throttle is wide open.
Another test is to floor the gas pedal as soon as the AOD shifts into second. If the TV pressure is close, the AOD will immediately perform a 2-1 downshift. Repeat the test again except from 3-2.
i gotta go out and adjust the cable because it doesn't do the downshifting at all and the funny thing is that my tranny doesn't use the same line pressure like the normal ones due to the valve body. it's set at 5-11 psi which is what TCI told me. i know what you guys are gonna say but, that's what 2 different techs told me it should be set at so don't worry and the transmission shop called to confirm it to before they drove the truck after the rebuild.
so i went for a ride after a small adjustment but it still is doing the same it was shifting into 3rd gear around 18mph @ 1700 rpm and OD was at 45-46 mph so the cable still has a tad bit of slack in it so i'll try to do one more adjustment to see if that helps but i don't want to go too far and mess things up!
so i went for a ride after a small adjustment but it still is doing the same it was shifting into 3rd gear around 18mph @ 1700 rpm and OD was at 45-46 mph so the cable still has a tad bit of slack in it so i'll try to do one more adjustment to see if that helps but i don't want to go too far and mess things up!
Something isn't right. And if you don't get this right, you can damage the AOD quickly.
If the TV cable is loose enough for your AOD to go into 3rd at 18 MPH, overdrive should engage a lot sooner than 45 MPH.
Do the 1500 RPM test I asked you to do in post #4 and post your shift speeds.
It sounds like the geometry between the carburetor and the throttle valve in the transmission isn't correct. Did you use the replacement TV lever for the transmission that Lokar supplied in their kit, and did you use the proper hole for a Holley carburetor? Look at the TV cable where is connects from the carburetor linkage to the throttle bracket bolted to the intake manifold. Is the TV cable flat?
so the cable doesn't have that much slack in it what i was meaning to say was i needing to adjust it again. all the parts are connected they way that they are supposed to be.
well i was able to get these photos added. that is the bracket that lokar had that would fit the demon carb to hold their cables on. they told me that the other bracket wouldn't work due to the way the carb was made but i don't know & at the time i didn't feel like taking any chances so i bought it. that front bracket is just a return spring bracket that i haven't removed for some odd reason but, it will be removed soon.
Subscribed. Will look to see if my shop manual has any adjustment directions, but I don't think the AOD was even out in 1981 so won't be in the manual.
Because I am not familiar with the Street Demon carburetor, I can't tell if the throw of the throttle lever is in sync with the pull of the TV cable from looking at a picture.
Since you are not going to do what I asked you to (1500 RPM test), try this:
With the engine off, have a helper get in the truck and floor the gas pedal. Pull the TV cable as far as it will go, and set it. The idea is to get the TV cable to be at full pull at wide open throttle. Then, release the throttle and check to see if there is any slack at all in the TV cable at idle.
If there is, the geometry is off. The shift points will never be correct and no setting will work until that is corrected first.
LARIAT 85
i'll give your test a try today but i gotta find a road to do that on. where i live there's plenty of traffic by my house. i'm not out in the country anymore. also like i said the TCI valve body is way different from the stock VB so that's why i don't want to do too much with the cable because we had a hard time getting the right pressure to start off with. i know that you guys are trying to help and i'm grateful i just don't want to mess up this transmission since it took so long to get it right.