Transmission Mounts, Cases, Housings

The transmission case, bellhousing and extension housing enclose internal transmission components and the torque converter or clutch and provide mounting points so the assembly can be connected to the engine and drivetrain, and the transmission mounts support the assembly in the vehicle. The case and housings are generally the most reliable parts of the transmission, but they can develop cracks and become corroded, and sealing surfaces and internal passages and bores can suffer scoring, nicks, gouges and other damage that can render them unusable. Our replacement cases and housings are an economical alternative to purchasing a new or remanufactured transmission. Defective transmission mounts can allow noise and vibration to be transmitted to the chassis and passenger cabin, and negatively affect clutch and shifting operation.

An automatic transmission bellhousing covers the torque converter and flexplate while a manual transmission bellhousing covers the clutch and flywheel. On some vehicles the starter is mounted to the bellhousing, and with manual transmissions the bellhousing also serves as the mount for the clutch release bearing apply fork or lever and may also serve as the mounting location for the hydraulic clutch slave cylinder or clutch cable housing. The bellhousing bolts to the engine block and is usually positioned with block dowels that engage with holes in the bellhousing. The bellhousings on both automatic and manual transmissions may be integral with the transmission case or separate components with the case bolted to the bellhousing. Inspect the bellhousing for cracks and broken sections, especially at the block mounting bolt holes and dowel pin holes and check the block dowel pins for damage.

Manual transmission cases have bores that locate the input shaft, output shaft, reverse idler shaft, countershaft and bearings and the case provides a reservoir for the transmission lubricant. Automatic transmission cases are much more intricate. They have many fluid passages and bores for components including the governor, oil pump, and clutches, accumulators and servos. The exterior of the case can be inspected with the transmission assembled, looking for cracks and other damage, especially at the case-to-bellhousing mounting ears, but thorough internal case inspections are only possible once the transmission has been disassembled and the case cleaned. Look for cracks, scratches, scoring, nicks, grooving, gouges and any other damage that would inhibit sealing and result in leakage at bores and gasket mating surfaces. Check the valve body mounting surface for warpage using a feeler gauge and straightedge and compare with specifications. Slight surface damage can be repaired with fine abrasive like crocus cloth and stripped threads can be repaired with thread inserts, but the case should be replaced if there is damage of greater severity.

The extension housing, also called the tailshaft housing, mounts to the rear of the transmission case, encloses the transmission output shaft and provides the attachment point for the driveshaft. It has a bore with a bushing for the driveshaft slip yoke and a bore for the speedometer cable drive gear or vehicle speed sensor. Inspect the extension housing for cracks in the case mounting and transmission mount areas and examine the extension housing-to-transmission case gasket mating surface and speedometer drive gear/speed sensor bore for scratches, nicks, gouges or other damage that would inhibit sealing. The driveshaft slip yoke rotates and moves in and out in response to rear suspension movement on a bushing inside the extension housing. If the extension housing bushing is worn, the slip yoke may not be centered in the bore, resulting in an extension housing rear seal leak. The extension housing bushing can be replaced and minor damage to sealing surfaces can be repaired with fine abrasive like crocus cloth, but cracks, broken sections and more serious damage requires extension housing replacement.

Rear-wheel drive vehicles customarily employ an engine mount at each side of the block and a transmission mount at the transmission extension housing. Front-wheel drive vehicles with transversely mounted engines and manual or automatic transaxles usually have at least four mounts – one at each side of the vehicle on the engine and transmission that suspend the engine/transaxle assembly, and a mount at the front and one at the rear of the assembly to control fore and aft movement caused by engine torque. The traditional transmission mount consists of two pieces of metal that attach to the transmission or engine/transaxle assembly and chassis respectively, separated by a rubber insulator. Some vehicles have fluid filled hydraulic mounts that can absorb more vibration without allowing excessive transmission or engine/transaxle assembly movement. The most advanced transmission or engine/transaxle assembly mounts are electronic “active” mounts that are soft at idle to absorb more vibration but stiffen at higher rpm to limit transmission or engine/transaxle assembly motion.

Vibration and noise transmitted to the chassis and cabin can be caused by collapsed mounts, while banging and thumping noise under acceleration, caused by the engine’s natural torque reaction, indicates one or more broken mounts. While vibration can be annoying, excessive transmission or engine/transaxle assembly movement is more problematic because it can negatively affect clutch and shifting operation. On manual transmissions and transaxles, clutch and shift linkage adjustment and function can be adversely affected by engine movement resulting in slippage and jumping out of gear, while on automatic transmissions and transaxles, engine movement can affect shift and throttle valve cable adjustment, resulting in difficulty shifting into gear, improper shift timing and missed shifts.

No matter what you’re working on, we have the replacement transmission mounts, cases & housings to restore proper transmission operation and vehicle performance. We offer transmission mounts, cases, bellhousings, extension housings and related components that are manufactured according to original equipment specifications, so when repairs are completed you can count on the performance your vehicle was designed to deliver. In addition to an extensive selection of every type of mount, and transmission cases & housings for all popular transmissions, we also offer brackets, adapter plates, mounting bolts, inspection plates, crossmembers, and more.

We also offer performance mounts made from high-strength steel or billet aluminum for impeccable durability, and/polyurethane that lasts longer than soft rubber and helps prevent against breaking due to deterioration after constant flexing and vibration. For racing pilots who push their vehicle off its limits, reinforced performance transmission mount is just the way. Specially crafted from extra durable hardened material to withstand the abuse of the harshest conditions, this type of mounts allows massive power to be delivered to the wheels instead of absorbing the energy into soft material.

At CARiD, you’re sure to find an extremely rugged housing for your performance transmission, as well. We carry the finest in rugged performance transmission housings fabricated to the highest standards to ensure a precise fit and serve you for years to come. Browse our extensive virtual selection of transmission tail, clutch and bellhousings, as well as Superglide and Powerglide transmission cases, Ultra-bell and Super Hydra bellhousings, Superglide tailshaft housings, plus SFI-Certified ATI and aftermarket cases intended for use in the most demanding of applications and unforgiving. All of these are built to be tough-as-nails to withstand power and torque extremes without unexpected breakdowns, and may have roller bearings or bushings supporting many of the transmission's rotating parts. Rolling bearings are great for use in high-speed machines with high load and use.