SRT STAGE I 4R75E

• Forward Clutch Drum Kit, 1 piece forged material VS stamped steel
• Sonnax Line Pressure Booster Kit
• High Capacity Direct Clutch Upgrade with Koleene Steels
• 5 Koleene Forward Steels

SRT STAGE II 4R75E

• Sonnax Smart-Tech High Capacity Forward Clutch Drum Kit
• Sonnax Line Pressure Booster Kit
• High Capacity Direct Clutch Upgrade with Koleene Steels
• 5 Koleene Forward Steels
• Sonnax Smart-Tech Direct Clutch Drum & Shaft Kit

4R75E Stage II Upgrades Details:

• Sonnax Smart-Tech High Capacity Forward Clutch Drum Kit: Forward clutch durability is an issue in performance applications. This problem often is addressed by eliminating the wave plate to fit more clutches, but plate removal creates harsh engagements and affects shift timing. Another common failure of stamped drums is cracking at the snap ring groove. The unique design of the Sonnax Smart-Tech high capacity forward clutch drum kit 76655-01K increases clutch capacity without abandoning the wave plate. The forged, one-piece drum prevents clutch drum breakage by eliminating weakness at critical stress points. The physically larger clutch pack area in the Sonnax drum kit increases capacity by 20% when using six OE-thickness frictions and steels. Using OE-thickness steels maximizes heat dissipation to prevent burnt clutches. The manufacturing process of the OE snap ring groove creates high-stress points around the circumference of the forward drum. The drum is active in 1st, 2nd and 3rd gear ranges and suffers the most abuse on a forced 4-3 kick down when it reapplies at higher pressure. The concurrent pressure from the forward clutch piston combined with the high stress at the snap ring groove causes the upper portion of the drum to split and separate at the groove. Depending on severity of the crack, this can result in no forward engagement or slipping in 1st, 2nd and 3rd gear. The one-piece, forged Sonnax drum kit is more durable than stamped drums and features increased groove depth for additional ring support.
• Sonnax Smart-Tech Direct Clutch Drum & Shaft Kit: Failure of the intermediate stub shaft and direct drum are almost inevitable when these transmissions are pushed to the limit. To maximize durability and improve clutch capacity in heavy-duty/performance vehicles, the Sonnax Smart-Tech direct clutch drum and shaft kit 76656-01K, the first upgrade to eliminate every critical weakness. Most failures in these units occur where the direct drum and stub shaft connect. Even other aftermarket upgrades that rely on a heavy-duty shaft will sheer in this area under extreme conditions. Unlike those two-piece assemblies, the all-in-one Smart-Tech easily handles the highest horsepower/torque levels. The unique one-piece clutch drum with integrated stub shaft is precision machined from high-strength steel to guarantee there are no splines to strip from the drum or weaken the shaft. The shaft itself is significantly thicker and 2X stronger than the OE. Due to its larger diameter, the integrated shaft must be used with the kit’s custom, heavy-duty sun gear. Insufficient holding power is another area these transmissions fall short, but installing thinner aftermarket steels and backing plates to increase clutch capacity isn’t ideal. Those components increase clutch pack flex and heat build-up, making them the primary cause of repeat burn-up. To improve both performance and long-term reliability, the Smart-Tech’s custom drum and piston hold an OE backing plate and seven OE frictions for 17% more clutch capacity than the six-friction stack-up.

4R75 BUILD PARTS LIST

• Borg Warner Complete Clutch Set
• Borg Warner Complete Steel Set
• Overhaul (Seal) Kit
• Bonded Pistons
• High Quality Transmission Filter
• Borg Warner Reverse & Overdrive Bands
• Bonded Reverse & Overdrive Servos
• Bonded 1/2 & 2/3 Accumulators & Covers
• Borg Warner or Raybestos Overdrive and Reverse Bands
• Bushings
• Pump Gears
• Updated Sonnax Pressure Regulator Valve
• Updated Sonnax Intermediate Spiral Sprag Snap Ring
• Updated Sonnax Overdrive pin
• Updated Superior Heavy Duty Separator Plate

4R75E Updates Details:

• Updated Sonnax Pressure Regulator Valve: These transmissions often have erratic line pressure, poor line rise and/or throttle-sensitive buzz. This can result in harsh or soft shifts and band/clutch failure as well as other drivability concerns. Worn pressure regulator valve spools allowing pressure escape are a common problem in these units. Installing Sonnax main pressure regulator valve 76948-09 restores normal line pressure operation in all ranges.
• Updated Sonnax Intermediate Spiral Sprag Snap Ring: These transmissions often experience failure of the intermediate roller clutch or mechanical diode during high-rpm conditions. Sonnax spiral retaining ring kit 76554RK incorporates a spiral snap ring that is staked to a locking ring to ensure ring contact with groove during high RPM conditions, eliminating blowout.
• Updated Sonnax Overdrive pin: In these transmissions, common problems are intermediate roller clutch, overdrive band or forward clutch failure, traced to the O.D. servo pin wearing the case bore. The oil circuit which releases or holds the servo off is present as forward clutch oil in 1, 2, 3 ranges. If this release oil leaks through the case, it can cause the O.D. band to drag and/or forward clutches to overheat. If band overheating becomes extensive, it may not hold in 4th gear, which can allow a neutral condition and excessive roller RPM on a re-engagement of 4-2 downshift. Replace the OE servo pin with Sonnax 76833E corrects all of the above problems.
• Updated Superior Heavy Duty Separator Plate: The Superior “Super Tough Plate” eliminates plate cracking and cross leaks caused by constant pounding from the 2-3 Accumulator Piston Spring Retainer on the stock separator plate. Made in the USA, the Superior “Super Tough Plate” is zinc coated, and extra thick.

At Shift Rite Transmissions, we’ve got you covered with our standard 1-year 36,000-mile transmission warranty when you purchase a new torque converter, giving you peace of mind from the start. For even greater protection, we offer upgraded warranty options: a 2-year, 50,000-mile warranty and a 3-year, 100,000-mile warranty, available for an additional cost. What’s even better? You don’t have to decide right away! You can upgrade your warranty at any time during your original 1-year coverage period. Stay protected for longer, on your terms.

At Shift Rite Transmissions, we want to ensure your transmission performs at its best! Our warranty covers everything under normal use, but it won’t cover damage to cases or shafts caused by misuse, abuse, or burn down due to operator error. For the warranty to remain valid, all warranty-related work must be completed at our facility in Kankakee, IL. The vehicle owner is responsible for shipping the transmission or vehicle to us for any necessary repairs. Please note that any unauthorized repairs made to the transmission will void the warranty. Please note that our warranty is non-transferable. We’re here to support you and keep your transmission in top shape!

Buyer is required to pay the core deposit up front. Core must NOT have any internal hard part damage or case damage, otherwise there will be additional charges deducted from your core deposit for the damaged hard part(s) or case. Initial shipping cost only covers one-way shipping. Return shipping cost for the transmission core is not included. Return shipping cost is deducted from your core deposit refund, after returned core passes inspection. All Cores must be returned within 30 days from date of purchase. Please visit our Core Return Section for more details.

Majority of units are in stock, in the unlikely case we do not have one in stock, they are quickly available, in most cases, as little as one business day. There are many different variations of this transmission model available so please make sure we get a VIN number when or after you place the order.