Big power 6r80 guys...

[FATHERFORD]

On my 2014(making 1300rwhp) I am having an issue with shifting.

Circle D 6r80
Circle D 2B
3.50 9"
28" tall tires

When I leave from a dig, in drive, the car will shift good 1-3, then in 4th it wants to shift to 5th around 116-120mph no matter what the tune commands. Then it will hunt gears, shut the throttle body, and basically fall flat on it's face. No matter what power level I'm at.

If I go to Sport 3rd gear from a role, go full throttle, bump to D it will pull to 150+ in 4th no problem.

Anyone else ran into something like this? My tuner, and apparently another tuner he is talking to are suggesting maybe going to a lower gear(3.00 etc.) but even he thinks it's a wacked out idea, but he is stuck.

I really want this 6r80 to work, but I'm to the point now of either a turbo 400, 4l80, or a glide....

 

[badbiach]

If you have spoken to a good 6R80 tuner, then I'm afraid your 1300 HP may have put the transmission in a bad place. I don't experience this problem, but I am a couple of hundred HP behind you. Good luck and keep us updated!

 

[wakebum2507]

subbed.

i plan on 1100-1200/1300 sprayed and will probably face these issues.

right now, i'd like to see 1150 all boost with the built 6R80, and 2.73's for roll racing only. will go to a 3.08 for drag use.

 

[slagburn]

1300 is past the 6r80's happy place. Swap time

 

[corepwn]

I would definitely consider running taller tires and longer gears. I've heard more than once that the 6R80/ECU shift more predictably at high power with the longer ratios. You have plenty of power to push it with longer gears and taller tires. As it is, you'd be on the limiter or well into 5th before the traps in the 1/4 mile.

 

[Holovacko]

I have much less power, but had a similar problem, with the trans not shifting as commanded in tune. Was a reputable e-mail tune, went to local Dyno tuner, who couldn't figure it out, ended up at Revolution, problem solved.

 

[wakebum2507]

So 3.08 or 2.73? (For roll racing)

 

[mastwolf]

Get it on a data log of the car doing it.

Log normal stuff along with things such as..

Gear Commanded
Trans Trbn speed
Desired converter slip
Torque Source

Then send it to your tuner and see if he can spot anything that coresponds to something in the tune.

 

[FATHERFORD]

Get it on a data log of the car doing it.

Log normal stuff along with things such as..

Gear Commanded
Trans Trbn speed
Desired converter slip
Torque Source

Then send it to your tuner and see if he can spot anything that coresponds to something in the tune.

Yeah I have it on datalog, not sure if trans trbn speed and desired converter slip. Might add those tonight.

 

[4VFTW]

I'm not a "Big power 6r80 guy" , but I did stay at a Holiday Inn Express once and imo its time to make the switch to a proven trans that relies less on software and sensors

 

[FATHERFORD]

I keep going back to 4l80. Can still be manual trans, holds lots of power, and still have OD.

 

[JUIC3D]

Datalog will definitely help. The power shouldn't have much to do with the shifting schedules though, assuming they're set up correctly. Mine broke that damn shaft a bunch of times but under moderate power (1100-1200) it shifted like it was supposed to.

4L80 seems like a good option since you want that overdrive gear. Either that or you could spend some coin and do a th400 with a GV. They're heavy though

 

[Stevem17500]

Hey juiced what shaft r u talking about the billet one

 

[FATHERFORD]

Going shorty glide with gear vender.... **** this 6r80... It's a great trans, but ill be going for 1500rwhp by the end of the year. Time to step it up I guess.

I want to be in the 7's like the cool kids

 

[Torchy]

Justin did you at least figure out what the issue is? I'm putting a built 6R80 in mine now.

 

[FATHERFORD]

Justin did you at least figure out what the issue is? I'm putting a built 6R80 in mine now.

It's tuning.....

And I'm to the point where it honestly just too much power, all the top tuners are telling me that. I could get a different tune, but I would be at the point JUIC3D is. Then later this year hopefully the new turbos will get me another 200rwhp or so, which would make me go to a different trans anyway.

 

[JUIC3D]

The shaft on the rear planetary. When it breaks, it breaks 2 other parts along with it, the planetary carrier and the 1 way reverse sprag-- $1000 in parts every time it breaks..

We even tried to weld it to give some extra metal and strength, but it just broke further up the shaft..

 

[Doug1227]

I'd have to assume that the shifting issues are tune related. I'm no where near your power level, but mine shifts perfectly now and I had a lot of issues before. HOWEVER, all of this talk about broken 6R80's has me concerned as well, since I've already bought clutches and billet intermediate and haven't installed them yet. Kinda wondering if I'm making a mistake. I'm putting in a new sleeved motor within the next month and plan on wring these 62's out for all their worth. Which most likely will be enough to break some stuff. Maybe someone will come out with some billet planetary shafts! I'd really like to keep the 6R80 if I can, but one breakage and it would really make me question my approach.

 

[JUIC3D]

I'm afraid a stronger shaft will just shift the power somewhere else which will then show the next weakest link. People have broken planetaries and cases and other parts for awhile now so this is nothing new. I think it's a great transmission around the 900-1000whp mark but above that, the reliability drastically suffers.

And even if someone does make a shaft and it ends up holding 1200+whp, I would still go with my glide due to the lack of a proper transbrake available for the 6R. Nothing beats bumping in the bottom bulb under full power

 

[FATHERFORD]

I'm afraid a stronger shaft will just shift the power somewhere else which will then show the next weakest link. People have broken planetaries and cases and other parts for awhile now so this is nothing new. I think it's a great transmission around the 900-1000whp mark but above that, the reliability drastically suffers.

And even if someone does make a shaft and it ends up holding 1200+whp, I would still go with my glide due to the lack of a proper transbrake available for the 6R. Nothing beats bumping in the bottom bulb under full power

what 1st gear you go with?

The trans guy I was talking to said since I was a full weight car he suggested the 1.76 or 1.8 first.

I'm pretty excited now that I'm doing this. Wish I did it in the first place.