Service Kits

More Information

Transmission service kits bundle the gaskets, seals, filters, friction clutches, and hardware you need for routine maintenance or a full rebuild — sold together so you're not hunting down individual components. Filter kits (the largest selection here) are the go-to for scheduled fluid services, typically every 30,000–60,000 miles depending on the transmission and driving conditions. Master rebuild and overhaul kits cover everything from soft parts to clutch packs and steels, used when the transmission is out and on the bench. Shift kits and valve body kits are performance-oriented, tightening up lazy or slipping shift feel in high-mileage automatics. When buying, match the kit to your exact transmission code — not just year/make/model — since many platforms use multiple trans variants. OEM-equivalent kits from Dorman, Sonnax, and TransTec are reliable for daily drivers; Sonnax and Superior shift kits are well-regarded for trucks and performance applications where shift quality matters.

Signs you need replacement

• Delayed or slipping gear engagement — If your transmission hesitates before engaging Drive or Reverse, or slips out of gear under load, worn clutch packs or contaminated fluid from a degraded filter are common causes.
• Dark, burnt-smelling transmission fluid — Fresh ATF is pink or red and translucent. Black or brown fluid with a burnt odor signals oxidation and clutch debris, making a filter kit and full fluid flush overdue.
• Harsh, jerky, or erratic shifting — Abrupt shifts or unpredictable upshift/downshift behavior in a high-mileage automatic often point to a worn valve body or shift solenoid issues that a shift kit or valve body kit can address.
• Fluid leaking from the pan or extension housing — A wet transmission pan or drips trailing from the rear of the trans indicate a failed pan gasket or extension housing seal — both covered by kits in this collection.
• Transmission fluid level dropping without visible leaks — Internal seal wear (output shaft, oil pump, final drive) can cause fluid loss that's hard to trace. Seal kits let you address these points without replacing major assemblies.
• Scheduled mileage interval reached — Many manufacturers recommend transmission service at 30,000–60,000 miles under normal use, or 15,000–30,000 miles under towing or stop-and-go conditions — regardless of whether symptoms are present yet.

Frequently asked questions

• How often should I replace my transmission filter and pan gasket? Most automatic transmissions benefit from a filter kit service every 30,000–45,000 miles under normal driving, or every 15,000–25,000 miles if you tow, drive in heavy traffic, or operate in extreme heat. Some sealed units specify longer intervals — check your OEM service manual for your specific transmission designation before setting a schedule.
• Are aftermarket master rebuild kits as good as OEM parts for a full overhaul? TransTec and Raybestos are the dominant aftermarket suppliers and manufacture to OEM specifications — most professional rebuilders use them routinely. For high-mileage daily drivers and work trucks, these kits perform reliably. If you're rebuilding a transmission in a luxury or performance vehicle and want exact OEM tolerances, sourcing factory soft parts may be worth the premium cost.
• What's the typical cost difference between a filter kit service and a full overhaul kit, and can I do either myself? Filter kits typically run $15–$60 and are a straightforward DIY job — drop the pan, swap the filter, clean and reinstall. Master overhaul and rebuild kits range from $80–$400+ depending on the transmission. A full rebuild requires the unit to be removed and disassembled, which is intermediate-to-advanced work; most DIYers tackle filter services themselves and leave full rebuilds to a shop.