Fine tuning tv cable.

[Sutter1stgen]

That's a pretty slick setup. Sonyou pretty much set the minimum tv setting, but it will get progressively high as you throttle it later. Mine acts somewhat similar, you can feel it down shift once at about 15 mph.

I still for the life of me can not get this thing to hold out above 50mph. It's starting to get frustrating. I'm half tempted to drop the pan and give the line pressure regulator a few more turns!! With the zip tie I can get it to hold out way too long, but I'm affraid I'm going to leg press the damn pedal through the floor, trying to get this thing to hold out just to 50.
Any thoughts??

Ernie from the one time I talked to him seems like the nicest guy. He questioned and explained to me in a way a cool uncle would have. It's nice to encounter people like that in this motorsport. Makes things more enjoyable.

[Sutter1stgen]

Well guys I just checked my pressures at my "line" and "reverse" ports. The line pressure was at around 130psi with the truck on stands at 1600rpm, at idle it was within spec. Reverse was at 320psi on stands, at 1600 rpm, and within spec at idle.

I can get my truck to hold out to about 49-50ish mph, and that's not quite enough. I think that the tv cable bends and flexes as I leg press on the throttle pedal. This not pushing as hard as cinching down a Zip tie. I don't want to ruin any of the aluminum parts in the valvebody by pressing so hard on the pedal, what do you auto trans gurus think I should do as far as increasing line pressure or another trick, to hold out the 2-3 shift a little longer??

[Sutter1stgen]

Alright guys I adjusted the line pressure regulator up another 1.5 full turns, and still,, nothing. I'm begining to get a little worried.

I may have to manually shift the 2-3 shift if this is really how it's going to be.

[ellis93]

I think to accomplish what you want,you'll have to screw with the gov weights. I can't get really specific on what to do because I truthfully don't know,but on GM stuff you change out the springs and flyweights to let it drag out the shifts when you can't accomplish with the detent cable.
I've dicked around with a 47rh enough now that when you adjust tbe line psi you raise your governor pressures in relation to ground speed,its suppose to be 1psi to 1mph. It's something to think about.

[Sutter1stgen]

Thanks for the input. I've researched a bunch, and I've even looked into the 1-2 & 2-3 shift spools, as in just modifying the 2-3 shift spool. But there really isn't any detailed info out there that I can find. My 1-2 shift point has always been flawless no matter the valvebody or trans I've had in the truck. It's always been the 2-3 shift. It was ether too late with my old 727, or too soon with my A518. And if I could just get those 5 more mph it would be perfect. My old 727 would hold out to 60 no problem, what gives with this trans?? Lol

[ellis93]

Do you still have the 727? I believe the gov weights are the same between the two trans,as far as fit and function. Transgo has kits too,for the gov,to fine tune them. I really think that's the silverbullet for your problem.

[Sutter1stgen]

Do you still have the 727? I believe the gov weights are the same between the two trans,as far as fit and function. Transgo has kits too,for the gov,to fine tune them. I really think that's the silverbullet for your problem.

And you know, you do bring up a good point, after a local trans shop rebuilt the 727 the second to last time, it held out the 2-3 shift way to long. Maybe they screwed with the governed weights since they were from a hot rod gasser background. Maybe I can fine tune the weights? But there is always the fact that zip tying the tv cable back let it hold out to 65mph before the shift. Which is 10 mph too much.

Idk

[Sutter1stgen]

I did some more digging and found a article on fine tuning the shift point on a old gasser 727. They changed the weights and raised both shifts 1000rpm. That would be way too much. They had a problem where the 1-2 shift timing was too early and they wanted it to mirror image the 2-3. So they chafed the 1-2 shift spring I. The valvebody from what I gather in the article. It raised the shift to the correct rpm as we'll leaving the 2-3 shift where it should be.

I wonder if I could stretch out my 2-3 shift spring a smidge and gain the same effect they did.?
Here's the article.
http://www.moparmusclemagazine.com/tech ... to_10.html

[Sutter1stgen]

http://moparforums.com/forums/f82/what- ... ndex2.html
In this forum they talk about shorter and longer springs. Looks like I'm going to fiddle with the 2-3 shift spring here soon. I'll have a reloading scale and two limiting blocks to see if the different pressures from stretching the spring.

Which me luck. Lol

[The_Head]

I wish you luck, I need help in this department. I don't know what spring to use. Mine either shifts way to early, or bangs the shifts.

[Sutter1stgen]

Well right now as we speak I'm headed over to my boss's shop. So your luck is well taken.

I talked with the guys at A&A transmission and they said they normally tailor the 2-3 shift by the governor, then fine tune the 1-2 shift with the shift springs.

But they said good luck finding weights for a diesel application, and that it could be done by stacking washer(s) between the valve and spring. They said to make sure it went over the stem of the valve and I should be good. I'll have my boss's reloading scales on hand to do a full spring compression test with and without the washer.

My 1-2 shift happens at 28-2900 rpm
My 2-3 shift happens at 26-2700 rpm, and that causes a surge. I'll find out the weight added by the washer, then I'll report back the rpm change.

[Sutter1stgen]

Well I almost forgot!!! The guy at A&A Trans told me to make sure I was pushing the tv valve in all the way, not just bottoming out the fulkrum arm. Well I checked that first and what do you know, it was inhibited by the plate that holds you're minimum line pressure screw, and line pressure adjustment.

So to just quickly check if that was the problem I smacked with a punch a few times where the arm had rubbed, and I've seemed to gain about a mm or 1/8" of travel, we shall see the outcome.

I bet when I cinched down the zip tie I was flexing the plate with the arm, causing me to get more revs!!!

Let's hope this works.

[Sutter1stgen]

Well that was disappointing!!! Not one damn bit of difference. I gained more inward movement, but no more gear holdout.

After turkey day I'll try shimming the 2-3 shift spring.

[Sutter1stgen]

Here's the cover for the shift valves and springs hopefully this will help you reference where they are.

Here is the spring that deals with the 2-3 shift.
slide it on out

For more referencing.

I aligned the spring on the shift valve and bottomed the stem on the work bench and found that the spring never fully compressed. I also tried to find a sae washer that would work, but all were to thick and would impede on the overall valve travel.

I measured the spring before I decided to stretch it. From the other link I found the spring looked to be about 1/8" longer than the one it replaced. I figured what the hell lets start there.

I stretched the spring out the best I could, and stopped at 1/8". I assembled everything back together and went for a test drive.

Part throttle shifts are at the same rpm. I locked my hubs in so I wouldn't have to worry about wheel spin in valet mode. Still lights the tires off till the 2-3 shift if I don't.
My 1-2 shift was at 2900rpm. I could actually barely feel the truck defuel at that rpm. Then came the moment of truth, the 2-3 shift went to about 2750rpm.

Not all that bad since it was not surging the charger. But not at a 3200 rpm defueled point ether. I would actually like to get some more rpm out of it and then dial it back with the tv cable. But it is a improvement from where I was.
Hope this helps some of you in the same boat as me. Don't be afraid of your valvebody!!!

[1STGENFARMBOY]

I wonder if you could stack shim washers for fine tuning ?