6L85E Specs, Info, How it Works

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Transmission General Description



The Hydra-matic 6-Speed RWD is a fully automatic, 6-speed, rear-wheel drive, electronic-controlled transmission. It consists primarily of a 4-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. There are four variants of the transmission, all based on torque capacity. Architecture is common between the variants, and component differences are primarily related to size.

The 4-element torque converter contains a pump, a turbine, a pressure plate splined to the turbine, and a stator assembly. The torque converter acts as a fluid coupling to smoothly transmit power from the engine to the transmission. It also hydraulically provides additional torque multiplication when required. The pressure plate, when applied, provides a mechanical direct drive coupling of the engine to the transmission.

The planetary gear sets provide the 6 forward gear ratios and reverse. Changing gear ratios is fully automatic and is accomplished through the use of a transmission control module (TCM) located inside the transmission. The TCM receives and monitors various electronic sensor inputs and uses this information to shift the transmission at the optimum time.

The TCM commands shift solenoids and variable bleed pressure control solenoids to control shift timing and feel. The TCM also controls the apply and release of the torque converter clutch which allows the engine to deliver the maximum fuel efficiency without sacrificing vehicle performance. All the solenoids, including the TCM, are packaged into a self-contained control solenoid valve assembly.

The hydraulic system primarily consists of a vane-type pump, 2 control valve body assemblies, converter housing and case. The pump maintains the working pressures needed to stroke the clutch pistons that apply or release the friction components. These friction components, when applied or released, support the automatic shifting qualities of the transmission.

The friction components used in this transmission consist of 5 multiple disc clutches. The multiple disc clutches combine with one mechanical sprag clutch to deliver 7 different gear ratios, 6 forward and one reverse, through the gear sets. The gear sets then transfer torque through the output shaft.

The transmission may be operated in any of the following gear ranges:

PARK (P): This position locks the rear wheels and prevents the vehicle from rolling either forward or backward. PARK is the best position to use when starting the vehicle. Because the transmission utilizes a shift lock control system, it is necessary to fully depress the brake pedal before shifting out of PARK. For safety reasons, use the parking brake in addition to the PARK position.



REVERSE (R): This position allows the vehicle to be operated in a rearward direction.



NEUTRAL (N): This position allows the engine to be started and operated while driving the vehicle. If necessary, you may select this position in order to restart the engine with the vehicle moving. This position should also be used when towing the vehicle.



DRIVE (D): Drive range should be used for all normal driving conditions for maximum efficiency and fuel economy. Drive range allows the transmission to operate in each of the 6 forward gear ratios. Downshifts to a lower gear, or higher gear ratio, are available for safe passing by depressing the accelerator or by manually selecting a lower gear in the manual mode range.



MANUAL MODE (M): This position allows the driver to select a range of gears appropriate for current driving conditions. Refer to the vehicle owner's manual for specific manual mode information.



Transmission General Specifications



Name

6L80

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

Torque Converter Size - Diameter of Torque Converter Turbine

258/300 mm

Pressure Taps

Line Pressure

Transmission Fluid Type

DEXRON VI®

Transmission Type: 6

Six Forward Gears

Transmission Type: L

Longitude Mount

Transmission Type: 80

Product Series

Position Quadrant

P, R, N, D, M

Case Material

Die Cast Aluminum

Transmission Net Weight (Approximate)

100 kg (220 lb)

Maximum Trailer Towing Capacity

Refer to applicable owner's manual



By HummerTech

[shakesvho]

I want one

[GMCwantsLS1]

Nice low first gear and two overdrives. I wonder if the drag is less than the 4L80e? Weight is not too bad either. You won't need 4.11's with this tranny.

[RedHeartbeat]

Awesome information! Thanks HT!

[shakesvho]

I wonder if the drag is less than the 4L80e

from what I read its alot

[Hit Man X]

Yes, the only problem now is the integration. Hopefully it can be done.

[HotRodV6]

Has anybody made any progress on the electronics of these new 6 speed trannys?

Id love to put one of these in my 03 Silverado.

[yellowdemon327]

would this bolt up to my truck? 99-02

[RedHeartbeat]

yeah, it will bolt up. Don't know if you'll need the 80e or 60e flywheel. Gotta get a custom crossmember for it. Not sure how you'll control the shifts. Maybe a standalone transmission controller will be needed. I'm sure they'll be pricey at first. Surely Transgo is working on a full manual valve body for these conversions but then you'll have to find a shifter to handle six drive gears to mount on the floor if you go full manual.

[04Denali]

there is a company that is making a stand alone controller for the conversion, was suppose to be done last year, I did a quick search and couldn't find it. I will look some more tomorrow.
Mark