V8 full built trans

[DERRAJZQ8]

First off who has a fully built transmission with a factory v8? Have you had any problems with it and if so what? I just had mine built and im runnning into a problem that seems to be a factory computer glitch and right now there is no way to fix this glitch. My tuner is looking for a solution but i wanted to know if anyone here has had an issue.

The problem is that the computer is commanding the trans to go into lock-up in second gear without it being in the programming. It just drags it for maybe half a second but its super annoying to drive it that way and not to mention not really good for it!

[olds88]

did u build it with servos or tune for more line psi

[fuzzkill]

4L80 :p

Should hold my supercharger fine ... but then again so can a properly built 4L60 ... just gotta break out the coin!

[ed-flip]

Jared if I'm not mistaken I think Sidecase might of had his built before he did the supercharger. But in any respect, he does have a built trans with supercharger. Did you buy a built trans, or did you have a local guy build it?

[05_quick4door]

Might have drilled the hole to big lol

[2littletime]

This is how I fixed my automatic issues. Auto slip =
T56

[subtlez28]

Originally Posted by 2littletime

This is how I fixed my automatic issues. Auto slip =
T56

I want to swap in a T-56 in the worst way! In fact I researched the swap on here before buying my truck.

Please, start a thread on your process on the swap.

Or comment on the one I started a while back:

Anyone swapped a T-56 in a stock V-8 Colorado / Canyon?

[DERRAJZQ8]

every things been done to it. servos, line pressure, clutches, input and output shafts, even has a vacumm modulator for main line pressure to produce consistance and quicker shifts. it was built by a local guy whos pretty much one of the best in the business. the problem was that Art Carr had his hand on it before and that he fu*ked it up! The internals have all been fixed now its just pretty much a computer issue. It was built to handle about 850HP

I would love a t56 but that would cause me to get in even more trouble

[ed-flip]

how much did it run you Jared?

[Karlen]

Ha, same shifter I have.

[05_quick4door]

850hp 4l60 eh?

So if it runs off vac now that's probably why you are having some issues

[ed-flip]

Originally Posted by 05_quick4door

850hp 4l60 eh?

I agree with this. I'd say more like 700 realistically. The weight of the truck being the main reason. Corvettes can squeeze 800 out of a 4l60e but they weigh considerably less than our trucks especially the crew cab. Either way it should definitely take anything you throw at it.

[DERRAJZQ8]

It ran me just over 3g's, but a lot of that was the shafts. i think the output shaft was like $600 and the input $400 or i could have that backwards idk. I believe him when he says 850Hp too, cause he has pretty much this exact same setup in some Impalas and the weigh in over 4400lbs and are making close to 900HP. And all the vacumm is controlling is the main line pressure and its way more consistant then the computer! The shifts are exactly the same firmness no matter what, unlike what the computer was doing!

HAHA! Ed, Maybe in like 10 years it wont be enough! If i ever get a real job, it'll be making over 800HP :P

[ed-flip]

Sweet sounds awesome man i'm happy for you. Did you do a stall while you were there?

[DERRAJZQ8]

Kinda. It's been all furnace brazed and it was loosened a little bit so it stalls at like 2000 now. Also has an upgraded lock up. It hits really hard now at 2000. It will break the tires loose at like 50mph now. Just wish I could drive it hard like I want to. Only get to flog it here and there till the computer is fixed

[Sidecase]

Originally Posted by DERRAJZQ8

It ran me just over 3g's, but a lot of that was the shafts. i think the output shaft was like $600 and the input $400 or i could have that backwards idk. I believe him when he says 850Hp too, cause he has pretty much this exact same setup in some Impalas and the weigh in over 4400lbs and are making close to 900HP. And all the vacumm is controlling is the main line pressure and its way more consistant then the computer! The shifts are exactly the same firmness no matter what, unlike what the computer was doing!

HAHA! Ed, Maybe in like 10 years it wont be enough! If i ever get a real job, it'll be making over 800HP :P

I am guessing that the vacuum modulator kit has the dummy resistor that tricks the computer into thinking that the force motor is still plugged in?. When or if you ever do a cam where you would have less vacuum at idle than stock this may cause issues. This is why i didnt go this route. I was looking at your tune over hptuners forum. There is definitely some things in it that made me scratch my head and I am not a tuner by any stretch of the word. Your shift times are more than factory, your force motor current table is way out of whack from stock. Also your wot shift mph is different from your 100% tps shift Mph in the part throttle tables. There is a guy on hptuners forum that has a post for how to tune your shift points and mph , think his nickname is coolaid , the post is in the transmission tuning section. It's a good read. Things in your tune may be that way by design because of the modulator.

[DERRAJZQ8]

Well shift point and all are not what they are suppose to be cause we are masking the glitch Roth now. So when the glitch is figured out we will tune it back to what it should be.

[05_quick4door]

did the stock have to mask a glitch?

seems silly if they did

[DERRAJZQ8]

No with the stock stall and clutches you didn't really notice it cause they just slipped a lot. With the upgraded clutches its strong enough to grab it and hold it now

[Sidecase]

Any luck yet? Did you manage to find a stock tune? Did your tuner try to do a write entire instead of just updating the changes? I know sometimes during the write process things can get wacky and sometimes corrupt the file. Maybe putting a battery charger on it before writing the the tune to the ecm. I don't know...just thinking out loud here. I know at work when we update new files to the ecm, the first step the manual says to do is put a charger on the battery.

I know that this seems kind of stepping backwards here but, maybe you can disconnect the wire from the tcc solenoid in the main harness were it plugs into the trans so that you can finish tuning the trans. Maybe toggle it with a switch until you get it figured out so you can at least drive it. Also with the wire disconnected from the tcc solenoid your problem should disappear. This would only be a temporary fix until you find a permanent solution.

The only mechanical thing thing that comes to mind is maybe a cross leak in the main valve body that could be pushing past the seperator plates and somehow pushing trans fluid / pressure into the tcc hydraulic circuit. But you are showing tcc energized in your logs so this wouldn't be causing your issue.

I was reading a little about your vacuum modulator setup on some other sites. I guess you have the one from transgo? I also see that they offer a boost bleed off valve that tee's into the line by the modulator. I am guessing you have this bleed off valve as well. I know this is how the old 700r4s used to control the line pressure.

This mod on the 4l60e takes the line pressure control away from the pcs and adjust line pressure based on engine load (vacuum = no load = low line pressure, no vacuum = high load = high line pressure) . Shift time (time to complete the shift), shift points, shift firmness (by the way of shift modifiers and torque management) are still controlled by the tcm. Most of these calculations are based off of the line pressure provided by the pcs table. I would put those values back to stock in the tune and maybe only bump the values down in small increments over stock values. Even though they no longer control line pressure for your trans, the values are still needed for other calculations inside the tcm. Mine are no longer stock but not very far from stock. I know that this has nothing to do with your tcc apply on the 1>2 shift, but the tcm is very finicky and any far out of wack values may cause the tcm to do things out of the norm just because it can't make sense of the values it has to work with.

Anyway, enough of my rambling on. I hope you get it fixed and share what you find. If you think it would help, I would be willing to send you a copy of my stock tune. Just pm me your email address. Later, Larry