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6L90 Performance Transmission Rebuild Kit - CDT Level 4

7/22/21: Currently on backorder - place your order now - it will be filled as soon as the part is available on a first-come, first-served basis. Rated up to 1100 RWHP | Detailed Instructions Included | FREE UPS Domestic Ground Shipping | NO core required for output carrier
Availability: Out of Stock - on backorder and will be dispatched once in stock.
In stock items ship within 1-2 business days.

This performance transmission kit comes with printed instructions for all of the items in the kit except for the Sonnax items. For installation instructions for Sonnax items, click here. If you would prefer printed instructions please click the checkbox below:

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$3,490.00

SKU: CDTL4PK/90

 

Picture for representation purposes only - actual contents may vary as we continue to develop our product.

 

6L90 CDT-BROC (4140 HTSR Billet Reinforced Output Carrier)

This part is designed for vehicles producing over 750 RWHP, Nitrous or Heavy Vehicles (including trucks, SUV's and CTS-V's).
It is a drop in part for easy installation.
4140 billet steel drive plate to strengthen the spline area.
The drive plate is milled and contoured to the planetary housing to eliminate any possible separation under a load.

CDT456L3-4/90 (4-5-6 CLUTCH KIT)
8  G3® Clutches
10 Lindered Steels (varying thicknesses)
1  Stepped Apply Plate
1  Wide Backing Plate
1  Snap Ring
2  Hi-Per Blue® Bonded Pistons

CDT456L3-4/90 offers 45% more clutch apply area than stock. G3® friction material is formulated to achieve minimal wear and maximize heat resistance. Lindured is a chemical and heat treatment process that hardens the steel, which results in less wear. Hi-Per Blue® Pistons are manufactured with upgraded High Performance Blue AEM material for superior thermal and chemical resistance, with better fit and performance.

104690-45 (BILLET INTERMEDIATE SHAFT & 4-5-6 CLUTCH HUB                                                                                                                                                  

One-piece 300M steel forging is heat treated and shot-peened for maximum durability. This shaft doubles oil flow to the clutch pack for improved resistance to heat and longer clutch life. The hub is designed for use with Powerglide-style, 45-tooth frictions. This shaft is designed for use without OE dampner.

 

CDT35RL3-4/90 (3-5-R CLUTCH KIT)
7 G3® Keyhole Clutches
7 Kolene® Steels (varying thicknesses)
1 Steel Plate
1 Apply Ring
1 Backing Plate
1 Snap Ring

CDT35RL3-4/90 offers 40% more clutch apply area than stock. G3® friction material is formulated to achieve minimal wear & maximize heat resistance. Keyhole Clutch design allows a significant amount of ATF to escape out of the O/D and I/D channels to improve clutch engagement. The pooling of ATF in the slot and hole separates the friction and steels when the clutch is disengaged reducing parasitic drag and heat build-up. Kolene® Steels provide a surface treatment the enhances wear & fatigue resistance.

CDT26L2-3-4/90 (2-6 CLUTCH KIT)
7 Red Eagle® Externally Splined Clutches
6 Red Eagle® Internally Splined Clutches
1 Externally Splined Steel Plate
1 Hi-Per Blue® Bonded Piston

Red Eagle® Clutches are designed to limit the amount of slip providing a shorter apply time, generating less heat. Hi-Per Blue® Pistons are manufactured with upgraded High Performance Blue AEM material for superior thermal and chemical resistance with better fit and performance.

CDT1234L3-4/90 (1-2-3-4 CLUTCH KIT)
6 High Energy® Clutches
6 Steels
1 Backing Plate
1 Snap Ring
1 Spiral Snap Ring
1 Snap Ring Kit
1 Hi-Per Blue® Bonded Piston

Hi-Per Blue® Pistons are manufactured with upgraded High Performance Blue AEM material for superior thermal and chemical resistance with better fit and performance.

CDTLRL2-3-4/90 (LOW-REVERSE CLUTCH KIT)
6 High Energy® Clutches
6 Steels
1 Hi-Per Blue® Apply Piston

Hi-Per Blue® Pistons are manufactured with upgraded High Performance Blue AEM material for superior thermal and chemical resistance with better fit and performance.

CDTVBPKL3-4/80-90 (VALVE BODY & PUMP KIT)
2 Boost Valve Springs
2 Clutch Regulator Valve Springs
1 Center Support Seal Kit
1 Pressure Regulator Valve Kit
1 Line Pressure Booster Kit
1 O-Ringed End Plug Kit
1 Pump Slide Spring

CDTMKL2-3-4/90 (MASTER KIT)
1 High Performance overhaul kit engineered utilizing premium materials for racing.
1 Bonded OE Valve Body Plate
1 Bushing Kit (includes extension housing bushings)
1 Pan Gasket
1 Filter
1 Oversized Pump Washer

 

We do not include welded hubs in Kit. In the beginning of R&D on this transmission we thought this area needing strengthening. However, in all the units that we've rebuilt we've NEVER seen one broken. Therefore, we deemed it unnecessary. Also, we do not include a billet pump rotor because the factory pump rotor has proven itself reliable (we have never seen one broken) unlike the 4L60E.

PLEASE NOTE: GM has a transmission that has the same outside dimensions as a 6L90 but uses one less clutch in all the clutch housings compared to a true 6L90. We call this transmission a 6L90LCC (less clutch capacity.) We also sell a performance kit that accommodates this transmission or we offer a combination kit that works for the 6L90 or 6L90LCC. Please refer to "Stock Clutch Capacity Chart" and "Length of Main Case Chart" on the "Transmission Specs" tab below to determine if you have a 6L90 or 6L90LCC.

 

 

 

  • Transmission holding fixture
  • Calipers
  • Dial Indicator Set
  • Bushing Drivers & Arbor Press for Bushing Installation (Bushings should only be replaced as needed)
  • Sealing Ring Protector and Sizer
  • Various Clutch Spring Compressors
  • Output Carrier/Shaft Lifting Tool
  • 1-2-3-4 & 3-5-R Clutch Housing Installer
  • Large Snap-Ring Pliers
  • Pump Alignment Tool

 

Upgraded Parts If you have an early pump cover (stator) that does not utilize anti-rotational tabs on the sealing rings or an early 1-2-3-4/3-5-R clutch housing that does not have the matrix stamp you will need to install a factory upgraded pump cover and clutch housing.

Transmission Tuning Please understand that proper tuning of the TCM and ECM are mandatory. All 6L80/90’s are torque base shifted units. The torque signal is calculated thru the ECM. Therefore, transmission performance & longevity are directly dependent on the delivered torque signal that’s calculated in the ECM. If this is not done properly, you will experience premature transmission failure. We also do not recommend maxing out pressures or deleting torque management completely because it will cause seal failure and/or hard part breakage.

Flushing Cooler & Lines We cannot stress enough the importance of flushing the transmission cooler(s) and lines, even if they are new. We recommend using a Hot Flush Machine Flush Machine or something comparable.                                      

Auxiliary Cooler You need to install a stacked plate auxiliary transmission cooler (not a tube & fin style cooler) rated for 25,000 GVW. The ideal operating temperature for this transmission is 180°or less. These transmissions have a tendency to run very hot – the cooler will lower operating temperature and recovery time which in turn will extend the life of your transmission.

 

Limited Warranty Statement

Circle D Transmission’s Rebuild Kits carry a 1 year, parts only warranty, exclusively against manufacturer’s defects. Warranty period begins at date of purchase. There is no warranty under the conditions listed below. This includes, but not limited to:

Improperly Stored
Improperly Installed
Improperly Tuned (EMC or TCM)
Misapplication
Altered, either by Owner or Their Technician
Torque Converter Failure
Inadequate Flushing of Transmission Cooler
Improper Fluid Level
Water/Engine Coolant in Transmission
Excessive Power
Accident
Neglect

Circle D Transmission will not pay for any fluids replaced in the event of a Kit failure.
Under no circumstances shall there be any labor warranty or other warranty coverage on Circle D Transmission Kits beyond the replacement of individual Kit components. We will not provide you with any cash refund except as many be required by law. Consequential and incidental damages are not recoverable under this warranty and are expressly excluded.

There is no warranty on broken parts such as, but not limited to: twisted splines, broken shafts or broken planetaries.

Warranty issues will be considered on an individual basis.

At least one of the following products must be added to your shopping cart to purchase this item:
  • CDT 3-5-R / 1-2-3-4 Clutch Pack Video Tutorial
  • CDT 4-5-6 Clutch Pack Video Tutorial