The Money Pit

I finally got the 700r4 trans in the car and drove it to the muffler shop for some 3" pipes.This was a short trip and I was surprized how each gear seemed to hang in a lot longer than the TH350 did.Felt like it didn't want to shift,but then when it did it was firm.I don't mind the firmness,but I think it should shift a bit sooner.Does the TV adjustment compensate for this?
I have the TV Easy setup from BowTie Overdrive set with the cam per the recommended starting point in the instructions,and have not played with the adjustment cam yet,but was wondering if adjusting the cam would alter the shift points,and if I adjust the cam,do I also have to reset the initial TV adjustment?
I don't intend to drive it much till I get the transmission temp gauge installed so I can keep an eye on it,but I figured some of you have been down this road before.

Jvette73

Important things first. No matter what carb you have or what TV cable setup you use either stock GM cable or the type BTO uses one thing definatly needs to be achieved for long life and proper operation. The TV plunger valve in the valve body needs to be fully peged closed when the gaspedal is floored. The best way to insure this is happening is to inspect it with the trans pan removed. You would have someone sit in the seat and floor the pedal while you look at the plunger valve underneath to verify its being fully depressed at WOT. Dont have the helper pull the throttle lever to get full throttle since sometimes that opens it a bit wider than the pedal will. the importance of this is to insure the highest possible pressure at higher rpm upshifts. The higher pressure will make a quicker and better holding shift to avoid unwanted clutch slippage. So have you verified yur getting full plunger depression under WOT?

I also have the BTO TV setup. Mine has the slotted type bracket thingy that connects to the carb linkage. i suppose this is what yur refering to as the cam. With this slotted linkage part it allows you to slid the mounting pin to different positions either forward or backward. Adjusting this connection point of the cable end in relation to the carb linkage center changed the geometry of the pull. Farthest forward depresses the TV plunger sooner in the pull giving it higher pressure sooner. This will have the effect of harder and slightly later part throttle upshifts. When the cable end connection point is moved farther to the rear it depresses the TV plunger less in the beginning which would give you softer and slighty sooner part throttle upshifts since the pressures will be lower in relation to the throttle position.

My kit also came with spacers that you add under the cable housing bracket. These spacers raise the position of the cable to keep it straight and level with the cable end connection point. According to BTO the cable must be level between where it comes out of the housing and connects to the linkage. If its not level then the geometery of the pull wont be correct and you wont get a full depression of the TV plunger.

So if yur set at the farthest point forward on the cable end connection, you can achieve slightly sooner shifts by moving the connection towards the rear of the slot. As you can see the slot moves upward as it moves to the rear. So you will need to add the spacers under the housing mount to raise the housing so the cable is level to its connection point. You will also most definatly have to re-adjust the TV cable position with the the little thing that you pop open on the housing. When you move the cable end connection rearward, the cable adjustment will need to be tightened(pushed in towards the firewall) to take up the slack of the new cable end position.

The BTO set up is a good one but it must be done correctly. Its either right or wrong. No room for this or that. One way is correct, and only one way. So sofer and sooner shifts can be had by moving the cable end connection rearward. But you must raise the housing to keep the cable level, and you must re-adjust the the TV cable to get full depression on WOT.

The GM type TV cables have a ratchet style housing adjustment. With those you depress the lock tab on the housing and push the adjustment tight all the way towards the firewall. Then you get in the seat and floor the pedal and the adjustment happens automatically as the GM housing allows the housing to "ratchet" out after the plunger hits dead bottom in the pan. BTO's adjustable housing is not like this. At least the one they sent me is not. When its locked closed the cable cant ratchet out if its too tight. So if the adjustment is too tight with this BTO style locking housing. The cable will become taught before the throttle is fully depressed. This is bad since it will prevent full throttle from being achieved, as well as possibly bending linkage at the carb or in the trans or possibly even breaking something. The GM style adjustment is sorta fool proof in this respect. It will always ratchet out when the cable becomes taught as the plunger bottoms out. So be carefull with the BTO setup not to make it too tight. No matter what the position of the cable end in relation to the linkage, at WOT the TV cable needs to be tight enough to fully depress the TV plunger, but not so tight that it prevents full throttle from being achieved by flooring the gas pedal.

With the BTO setup, regardless of the position of the cable end connection, weather forward for more agressive and later part throttle upshifts, or rearward for sooner and softer part throttlw upshifts, when its set up correctly, it will still achieve full TV plunger depression at WOT. This is why its important to use the spacers to keep the cable level comming out of the housing and onto the linkage connection. If its not level, the whole design of this versitile setup will be undermined as the geometery of the pull will be thrown off.

MIKER

JVette73 explains this stuff very well and I can only provide roughly the same info in a different way. Hope it helps.

Proper TV cable adjustment would likely solve your problem. This is the most common and the easiest of three possible adjustments used to program the shift characteristics.

I have a 0-300 psi gauge installed to aid setup of my TV. It eliminates a lot of guess work and or transmission pan removal for setting intial TV plunge from off idle through WOT and for verifying overall line pressure.
Ideally, your TV cable should be set so that the TV plunger (in valve body) is activated immediately from just off-idle and should continue linear engagement all the way to when you reach WOT. Full plunge of throttle valve should be simulateous with WOT. One should not limit the other.
The "TV Easy" setup is supposed to help correct poor linkage geometry to enable this linear plunge.
In summary, the TV cable adjuster can be used to set the correct initial 'at idle' position of the TV plunger. After that, pull rate and final plunge @ WOT is adjusted via the "TV Easy" setup.
Bottom line is "IF IT SHIFTS WRONG, IT WON'T SHIFT FOR LONG". However, it's much better to have your TV cable too tight (higher line pressure) than tooo loose with low pressure, soggy shifts.
Even after you get get the TV pull set up perfectly, which is next to impossible, you may still desire different shift timing. You can make adjustments to the governor and or spring changes to the shift valves. All in all, its quite a pain to perfect the shift timing and firmness of a 700R4 or 200R4 but well worth the effort.
Good luck and have fun with it!
:cheers:

mrvette

I had my 700 built by a local shop here and told him I wanted the most wicked shift possible....well he supplied a Superior/fairbanks shift kit...supposedly a good one.....well IMO NO.....

the 400's I have had in the past were million mile units with Trans-Go, Gil Younger shift kits...

NOW I know the 700 has 3/4 clutch failure built into the unit....thing is....to get better oiling/cooling into the 3/4 clutch pack....NOW to increase shifting firmness, I think eliminating or blocking the accumulator valves to the clutch pack would greatly increase firmness....

frankly some day,...I want to try that....just as a filthy oily experiment, and tell you what.....I have done this before decades ago...and it worked like a CHARM!!!.....damn thing tossed shifts that would kick the freaking car to the MOON....

NOW....I dunno how this will come about, or even IF it will....but at some point I"m going to get upset enough to just TRY IT!!!

GENE

Jvette73

BTW, I will also add that its actually better for the tranny if it shifts a bit later. It brings the rpm up higher before the next upshift which will drop it in to the next gear at a better point. It makes for smoother engagement and less wear and tear in the internals of the tranny. You can easiely get used to it. I like mine shifting a bit later on part throttle anyway. I can sorta drive out each gear so to speak. Kinda like drivin a manual. Just push out the gear then let off the pedal a tad and presto, it shifts up, ready for you to push out the next. Sure it will eventually shift up on its own if you keep the throttle at a steady position. But when its programed to shift a little later on part throttle, it gives you the controll of exactly when you want the upshift. Just ease up a tad on the pedal when yur ready for the next gear. Full throttle upshifts are a different story. They are controlled mainly by the govenor. To adjust them, either mods to yur existing govenor, or a govenor swap is the fix. Or if it shifts up to early WOT, you can always shift manually with the stick. My BTO 2004r was shifting up too early at WOT. I could shift it manually myself no prob but the wife drives it too and her skills of watchin the tach and manually shifting are another story. She likes to have fun and floor it too so I felt compelled to make the adjustments so it would upshift automatically at a higher rpm. First I tried to modify my existing govenor by lightening the weights by drilling holes in them. In the process I tweeked the govenor all out of whack and was afraid to put it back in. So I contacted PTS and they sent me a modified govenor. That did the trick. It brought my full throttle upshifts from 4000rpm up to just over 5000rpm. Now she, or even me for that matter, can just leave it in D and forget about it. When I really wanna get serious I still manually shift since I like to hold it out to about 5500rpm. One of my favorite things about this tranny is the full throttle upshift from 3rd to 4th. It engages very solid and makes the azz squat and the nose lift. This is a pretty cool feeling since yur doing over well 100mph at this point. Ive never brought 4th to the redline. Ive had it up to 135mph and it was tachin around 4500rpm at that speed.

thanks for the compliment MIKER :cheers:


[Modified by Jvette73, 5:48 PM 6/1/2003]

The Money Pit

Guess I'll play with the cam some when I get the car back from the muffler shop.I installed a B&M Megashifter,so manual gear chaning will be a blast,but I'm afraid in the normal day to day driving that shifting too high with 500 lbs of torque would make for a short transmission life.


I gotta make this last for a while to appease the boss. (wife)



[Modified by The Money Pit, 8:58 PM 6/1/2003]

MIKER

Gene, you are correct. Preventing the accumulator from functioning will produce a “GREATLY” increased firmness in shift. However, it is my understanding that without additional modifications the SHOCK induced by non-accumulated shifts may cause other parts to fail. My accumulator is equipped with a modified spring that helps to provide a crisp shift yet continues to provide some damping.
Do you know any good performance trans builders that can provide you with technical assistance? I picked up on some transmission knowledge from my builder back when he did my 700R4. He is eager to share knowledge but he moves fast and is too far over my head to catch it all during short visits! :lol:
If he didn’t live so far away, I would probably try to trade him my labor for training. He’s a good Dude with a LOT of knowledge.

mrvette

You know, MIKER< years ago, I just removed the accumulator valve entirely and blocked the passages, then later on in the turbo series...350-400, the spring were cut.....NOW in the 700r4's the talk of stiffer springs....I dunno...
I thinking of just taking them out, and putting the pistons of bottom of the hole and leaving it there, see what happens.....I suspect I"ll get the shifts I dream of....

GENE

MIKER

It's certainly not going to immediately fail just because you disable the accumulator. One thing for sure, if ya don't like the way it feels, try, try again! :D
Continual bone crunching shifts just have to be hard on a lot of parts. Maybe it won't be as harsh as I imagine it to be.
Let us know how it turns out.

mrvette

Miker, I think the only things to be hurt would be the planet gear sets, and they make a 5 planet set for it....3 is stock.....
the only other thing would be the 2/4 band...and that has torn the metal around the stake in the case and the metal is stressed where the pin from the piston presses into it on the other end--to apply the thing...so the band would have to be welded on the strenthen the ends....lovely, don't know what effect that would have on the band material...have to get my buddy to look at it sometime....

GENE