CentralCoaster

I'm having frustration with a Bowtie Overdrives 700r4 and have some questions about the 3-4 shift and torque converter effects on line pressures and idle rpm drop in drive.

Looking for some straight answers, PM me if you can help.

Everyone else's best suggestion is buying a new trans and t/c and carb.

Smooth

My suggestion would be to pm Petek. You Know hes the Man

CentralCoaster

Yeah but he doesn't respond to his PMs much. I'm tired of bugging him.

Pete K

Kevin,
Remind me again what the specifics were.

CentralCoaster

I fixed the problem with the converter signal wire being crossed with the temp sending unit, but it still drives horribly.


Idle drops 400-500 rpm from Park to drive, so I have to set the idle really high to keep it from stalling in Drive, and this is complicating my efforts on tuning the carb.

When shifting into 3rd, transmission drops into overdrive right away and usually won't come back out under throttle. The RPMS are really low at this point ~1400 RPMs and getting on the throttle will just cause it to sputter and backfire instead of downshifting. So I have to manually shift back into 3rd.

Shift points feel perfect on 1-2 and 2-3 shift. TV cable was adjusted by my seat-of-the-pants dyno.

I think the converter came with the trans from Bowtie overdrives, but I know nothing about it, except that it came packaged with a lockup wiring kit.

Pete K

If you wire it up temporarily as a 4th gear only lock up, it may help to isolate a lock up problem.
I wonder if the rpm drop from park to drive is related to the converter lock up?


On the carb stuff, I have seen the tv cable over extend at wide open throttle, (or close to it), causing the shift troubles. Sonnax makes a correction kit for this for little money $5 or so.
It is a spring that attaches to the end of the throttle end of the tv cable. It causes the last part of the cable to have progressive travel.

Pete K

I have had horrible luck with the aftermarket lock up kits as well.
They always seemed to lock up the converter too soon. I have not used one in over ten years though.

CentralCoaster

The lockup wiring is fine, but maybe I'll put a light on it just to be sure.

I think the way its wired, it can only lockup in 4th.

Do you have any thoughts on the 3-4 shift? It'll shift into 3rd at say 2500 rpm (normal accel, low throttle) and then instantly drop into 4th and bog down to 1400 rpm and stay there.

Pete K

One of the drawbacks to 4th gear only lock up is the tendancy to bog if the gear ratio in the rear is on the high side.
For example, c4 l-98 cars with 2.59 gears and a superram would bog terrible.

The 3-4 shift could very well be the tv cable overextending due to the geometry of the pin location on the throttle shaft. I will try to dig up the sonnax corrector part number. It is cheap and fixes this condition properly most of the time.

CentralCoaster

If that was the case, wouldn't it be a problem in every gear?

Pete K

Although that would seem to be the case, the common symptoms would be identical to yours. I have never run across the problem personally, but the fix was recommended by Dana at Probuilt.
Sonnax AS1-01K TV cable corrector is what you need. www.transmissionhead.com has it, but so would any sonnax dealer. Price is $5. I would give it a try.
The tv cable pivot pin typically has a range of motion from 4:00 to 8:00, or vice versa depending on the pull direction of the cable. Crossing the 4 or 8 clocking will slacken the cable and result in the pressure change.

Pete K

Also,
If you have not done it already, verify that the tv cable pivot is 1.125 inches (centerline to centeline) fron the throttle shaft.

REDC4CORVETTE

I know what you are going through.I finally gave up and set my 700r4
to a reverse manuel valve body and a 9" TQ converter.
I did that because I was having the same problem as you.
I tried a thousand ways to set the tv cable and when I got it close a week or two later it would start to screw up again.I got pissed and floored it and burn up the trans.
I was using the holley levers and screw in cable retainers,for the carb,tried one of the levers for a dodge and ground it down,I later found out it was the angle like the throttle that was flexing and bending .I also had a problem with full throttle,I made a bracket and finally got the throttle cable just right and it runs great .
I thought by making the tv cable as tight as possiable that would make it shift like I wanted, but I lost my kool and just blasted it.

PBA

Since there is only 78 degrees of travel at the throttle blade, the setting on the clock is closer to 4:45 - 7:15 as per clock movement. This will give you a straight line as far as pulling on the TV cable.

CentralCoaster

I haven't had any time to mess with it much, although I found out my brake light circuit isn't working anymore, so the TC isn't getting an unlock signal. I'll fix that and do what Pete said, simplify the TC wiring, and put a light on the dash that tells me when it's locked.

The TV cable has an install kit from Barry Grant on there, but I'll check on the prev owner's adjustment.

After I fix the brake circuit, I'll wire up a low-vacuum release switch to the TC, and then consider changing the converter. Didn't all the cars from the factory have a low vacuum release switch for driveability?


Also, what's a good stall converter for a commuter truck with ***** that'll do some towing on occasion? I want good freeway mileage too, if that's asking too much.

sami85L98

No, my tranny built by pete and this is just beyond nice what i expected, anyway check my sig for mods, i was having trouble with 3-4 shift too soon, mine is 3.54 gears and SR with 219 cam ...... i sent governor to pete and he modiy governor weights to 10 grms i think and now it shift perfect (3-4), no bog down.

Regarding TV cable u can just go to tranny guy locally, and tell him u need TV cable extender, its a small piece of plastic with a small spring attached to it, heck he might through u for free as too cheap.

Also if i remember Lockup is feed into chip when to lockup i might be wrong with this, but when i burned chip from Tjwong he asked me when i want lockup to occur at what speed, by default i think it comes at 50 mph. But hopefully pete k will resolve ur problem, give him little break he got a full time job too besides transmission.

Pete K

Sami,
I am pretty sure that Kevin did not mean anything. He sent me a few pm's that I did forget to return. Sometimes, I misunderstand someones description of the problem as well. Regardess, hopefully we can get to the bottom of his problems and sort it out.
Although I carry the trans torch here on the forum, I know for fact that we have some part time lurkers here that are much more experienced than me, but do not frequent much. Hopefully this keeps it at the top for Kevin

Pete K

2200-2500 is as high as I like to go on my own street driven stuff, if it is 12 inch.
9.5 incher will stand a few hundred more(3000 or so) and make similar, or less heat.

edar

when i got my car it had a fresh new re-built stg II race tranny from maddog transmissions in tampa florida. Wow, that is a slick tranny. Check their web page. I believe they can ship to you or your local installer. Pretty funny web page also. Something like www.maddogtransmission.com I think.

CentralCoaster

I measured it at 1.55" from the throttle shaft. This is using Bowtie overdrive's "TV Magic" for Demon carburetors. It allows for reclocking the TV attachment, but it looks like the radius stays unchanged.