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Manual Shift 6 speed 4L80E

Dr. Custom Werx

Dr. Custom Werx

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So im not building my chevy right now but this seems like the crowd of people who might know. im building an all wheel drive 1984 buick regal with a 3500 driveline, cab and chassis 14 bolt rear and a supercharged big block on propane and need some insight.

My initial plane was to use a 700R4 but i was hangin out at the shop when someone mentioned they read "on the interweb" that 4L80E can be made a 6 speed. i said nuh uh but thought again all you would have to do is use overdrive as a gear splitter. i been searching all night on this and can only find that TCI makes an entire kit including transmission for this and that everyone says this is not a new idea, its been around since the 90s but it was manually shifted then.

I am perfectly fine with manually shifting if i can get 6 gears out of my 4L80E but i cant find anywhere that tells you what kits is offered or how to do it. any help would be appreciated.
 
So which part of this:

Dr. Custom Werx said:
So im not building my chevy right now but this seems like the crowd of people who might know. im building an all wheel drive 1984 buick regal with a 3500 driveline, cab and chassis 14 bolt rear and a supercharged big block on propane and need some insight.
Click to expand...

makes you feel like this would need an OD transmission? Why are you so psyched for the so called "six gears" out of a 4 speed trans?

I believe that many OD transmissions engage different sets of their planetary gears to achieve more than, say, the four gear ratios they claim to have. Doesn't really make it more than a four speed. And while it might be useful for a DD truck, why is it anything to worry about on a trar?
 
I saw an article covering that conversion IIRC it was TCI that did it. I'll take a look around and see if I still have the article.

Gus
 
Not bad when your average rebuild on a 4l80E is around 2400.00
 
38377k5 said:
So which part of this:



makes you feel like this would need an OD transmission? Why are you so psyched for the so called "six gears" out of a 4 speed trans?

I believe that many OD transmissions engage different sets of their planetary gears to achieve more than, say, the four gear ratios they claim to have. Doesn't really make it more than a four speed. And while it might be useful for a DD truck, why is it anything to worry about on a trar?
Click to expand...
well.... i want overdrive. nothing makes me feel that i "need" it.

Speedo said:
It's on TCIs web site. http://www.tciauto.com/Products/6x/

Gus
Click to expand...
like i said in my original post, it seems the only thing i can find for information online is regarding TCIs transmission. but in almost every place i have searched someone mentions a company came out with this years ago but it had to be shifted manually. i did find that someone said this company was JET but no other information.
 
Well, did anyone notice that the final OD is still .75? So they just add some mid range gears is all. Not worth 6k
 
Not a bad deal when you look at how much an Allison trans goes for. You'd have to be pretty bent on having a six speed trans though. Hot rod type application comes to mind. Keep the engine in the power band if/when driving hard. But for a trar, you might be better off using just a plain 4L60/80. You'd still have OD so you arent losing anything but those two extra gears inbetween.
 
If 1st gear and 4th are still the same, I don't think it's worth it. It's my opinion that even car manufacturers are putting too many gears into their transmissions these days. With the exception of a deeper OD gear. These cars just seem to be constantly shifting themselves.

I don't see a need for all those gears in an auto trans for a truck, even a custom build. The typical 4spd auto with OD should suffice for your application.
 
496truck said:
If 1st gear and 4th are still the same, I don't think it's worth it. It's my opinion that even car manufacturers are putting too many gears into their transmissions these days. With the exception of a deeper OD gear. These cars just seem to be constantly shifting themselves.

I don't see a need for all those gears in an auto trans for a truck, even a custom build. The typical 4spd auto with OD should suffice for your application.
Click to expand...


Yeah, my thought was the OD still being .75 with no change. If it had a higher OD .7 or even .65 you could run taller gears, say 4:10 and still have nice highway RPMs.

My 4:56s and .75 and I get a nice drivable 2200 at 70 RPM with 35ish tires.
 
In theory you will get better MPG out of more gears if the the shift points are correct for your vehicle. The idea is that you motor will stay in it's narrow torque band which is where it makes the most efficiency. Just slapping a six speed box in there does not mean that you have achieved this. None the less, this is why auto manufacturers are going in the 5-6spd auto direction. Once on the highway, you are correct, only final drive ration will determine MPG and it doesn't matter how many gears you have.

It's should also be pretty obvious that more gears (to a point) are better for towing applications. This is why diesel pickups now come with 5-6spd gear boxes and the same reason why BIG RIGS come with 10-20spd gear boxes.
 
for everyone saying its not worth it and i dont need it.... out of my thread. lol its not like i have to purchase different gear sets and everything. i just have to figure out how to shift overdrive independently. 1st, 1stOD, 2nd, 2ndOD, 3rd, OD
JET used to make a kit and i believe it included a different or a modified valve body
 
For $6k I'd find another way. Do you need it? Probably not. Is it cool -> yes. So from a gear head standpoint I say go for it and give it a try.
 
Not on a 4l80e. But you could use a 6l90e. ( I lust after this for my next street/off road truck. Look at that ist gear ratio and the double overdrive. Yum!)

The Hydra-matic 6-Speed RWD is a fully automatic, six-speed, rear-wheel drive, electronic-controlled transmission. It consists primarily of a four-element torque converter, an integral fluid pump and converter housing, a single and double planetary gear set, friction and mechanical clutch assemblies, and a hydraulic pressurization and control system.

The transmission is equipped with DSC(Driver Shift Control) which is a "manual" mode, and utilizes rocker switches on the steering the driver may select upshifts or downshifts An upshift is requested by pushing either + button. A downshift is requested by pulling either + button rearward toward the driver.

RPO Codes
MYC

Production Location
Ypsilanti, Michigan (USA)

Transmission Drive
Rear Wheel Drive

1st Gear Ratio
4.027

2nd Gear Ratio
2.364

3rd Gear Ratio
1.532

4th Gear Ratio
1.152

5th Gear Ratio
0.852

6th Gear Ratio
0.667

Reverse
3.064

Diameter of Torque Converter Turbine
258/300 mm

Pressure Taps
Line Pressure

Transmission Fluid Type
Dexron VI

Transmission Fluid Capacity
9.54 L (10.08 qt) - 6CDA

9.71 L (10.27 qt) - 6CZA

11.92 L (12.60 qt) - 6CYA

Transmission Type: 6
Six Forward Gears

Transmission Type: L
Longitude Mount

Transmission Type: 80
Product Series

Position Quadrant
P, R, N, D, S (some models)

Case Material
Die Cast Aluminum

Transmission Net Weight
95.1 kg (209.7 lb) - 6CDA

96.7 kg (213.2 lb) - 6CZA

103.7 kg (228.6 lb) - 6CYA


Or you could slap a gear vendors overd drive on the output of the 4l80e and get 8 forward gears but that becomes a pain to shift.


Rufus
 
thanks for the input on the 6L90E but im looking for information on the 4L80E
you guys aren't reading. i dont want to go with the TCI kit
 
Ahhh, but I did read your request, and I gave you the option under the 6l90e trans.

"Or you could slap a gear vendors over drive on the output of the 4l80e and get 8 forward gears but that becomes a pain to shift."


The 6l90e is definitely the better option in my opinion.
 
for more info in the gear vendors overdrive on a 4l80e.

Axle Ratio 5.13 4.88 4.63 4.56 4.10 3.73 3.42
Trans Ratio Final Drive Ratio
1st 2.48 12.72 12.10 11.48 11.31 10.17 9.25 8.48
Over 1.93 9.92 9.44 8.95 8.82 7.93 7.22 6.60
2nd 1.48 7.59 7.22 6.85 6.75 6.07 5.52 5.06
Over 1.15 5.92 5.63 5.34 5.27 4.73 4.31 3.95
3rd 1.00 5.13 4.88 4.63 4.56 4.10 3.73 3.42
Over 0.78 4.00 3.81 3.61 3.56 3.20 2.91 2.67
4th GM O/D 0.75 3.85 3.66 3.47 3.42 3.08 2.80 2.57
Double OD 0.59 3.00 2.85 2.71 2.67 2.40 2.18 2.00




As far as getting 6 forward gears INSIDE a 4l80e transmission, I don't think it is possible.
 
You'll be hard pressed to find anything off the shelf. Seems there was a Powertrain Control Solutions that toyed with the idea, but didnt produce anything. And from what I read, JET had an issue with making the controller reliable and consistant, but still cheap enough to market.

I'd say if you really want this, you'll have to find someone who can do programming work and get a custom one-off controller made. And you still have the issue of a valvebody. Otherwise, you can use the 6L90 or an Allison with a standalone controller. I dont recommend the Gear Vendors since it wont work with the front output on the t-case.
 
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