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Pilot Bushing

GM Gen III & IV Engine

to

GM Transmissions

 


A precisely sized pilot bushing is essential to proper manual transmission installation. We generally recommend a bronze bushing for Jeep applications (when available) as they seem to better endure the harsh environment of a clutch housing. However, with proper installation a needle roller bearing is acceptable, so long as the transmission input shaft hardness is up to the hardness of the needle bearing.

Product & Features

Novak pilot bushings are made from quality Oilite bronze alloy, or in the case of a bearing, a quality needle roller assembly. Often, in adapted applications, a custom outer diameter, inner diameter or even a pressed ­in sleeve are used to meet the needs of that particular application.

Applications & Compatibility

Transmission

The GM SM420 & SM465 Truck transmissions use a ~19/32" pilot tip diameter. It is always a good idea to verify what you have to be sure.

Engine

Fits all standard GM Gen III & IV cranks installing in the outer, rear bore of the crank (where an automatic transmission usually locates). The LS architecture shifts the face of the crank about .4” forward of where a Gen I or II would be in relation to the rear face of the block, because of this the pilot needs to sit rear of where it would be in an earlier engine to be in the same location relative to the block face.

There are several exceptions to this rule that must be watched out for. Some 4.8L & 6.0L engine from 3/4+ ton truck applications have a crank face in the standard Gen I position but with the LS bolt pattern. These are a special case and require special treatment with regards to transmission attachment. The 4.3L V6 also requires special attention through the later years. If your crank looks like the photo to the left, use these pilots otherwise, it will use 1st gen pilots.

Related Products

No additional products are recommended, but if you are unsure of your ability to install the pilot bushing / bearing the first time, you may wish to order an additional unit if your project's time is of the essence.

The correct Flywheel is essential on an LS based engine.

Block_LS400-35X

As are the unique high strength bolts:

Block_330-2802

The BR4 ring is used to enable use of the SM465 5-1/8” bore bellhousing with 4-11/16” 

Block_BR4

Installation Requirements

alignment_of_a_bellhousingRemoval of the old bushing and cleaning the crank bore is required prior to installation. There are a number of official and unofficial methods out there to remove the old bushing/bearing. Hydraulic removal using inserted grease behind the bushing (or wet paper towel, etc. and a precisely sized rod is a classic. Our preferred method is a slide puller available from your local parts store as a rental tool if you don’t own one.

A proper drift tool or driver is recommended for installation. Do not coat oiled bronze in grease, as this plugs its pores and will not lubricate properly afterwards. Installation as the bushing comes is acceptable, though soaking it for a day or longer in clean engine oil prior to installation is preferred. Freezing the bushing and lightly warming the crank can ease the installation. Pilot bushing and transmission input and main shaft damage are inevitable if the bellhousing and transmission are not centered concentric and parallel to the engine face. We recommend the use of a dial indicator to verify that your bellhousing and engine are centered on the bellhousing bore. See The Novak Guide to Clutches, Linkages and Bellhousings for directions on this method.

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