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Adapting

Chevrolet & GM Engine Bellhousings

to the

Jeep New Venture 3550 Transmission

Jeep NV3550 Adapter kit to GM Bellhousings

This conversion kit joins the 2000-2004 Jeep NV3550 overdrive transmission to the standard GM pattern bellhousings.

The adapter is precision designed and expertly CNC machined from alloy aluminum. Its thick cross-section provides ample thread engagement and high structural integrity. Precision indexing is achieved through locating dowels to the transmission and bearing retainer to the bellhousing. This adapter is 1" thick for a total adapted length of 17.7".

The adapter installs onto these transmissions with no change of input gear or other transmission internals. Cutting the transmission input shaft is not required as the adapter spaces the transmission properly for the GM crank and clutch assembly. A new pilot bushing is required for this assembly. See Related Products below for the one matching your particular GM engine.

Kit Contents

Included are the adapter plate, bearing retainer (which serves as a centering index for the GM bellhousing and clutch release bearing sleeve) and required hardware.

Applications & Compatibility

Compatible Jeeps

This engine conversion is compatible with TJ & LJ Wrangler Jeeps in which this transmission was native. It is also compatible with CJ7 and longer Jeeps in which builder may be retrofitting this transmission. CJ5 Jeeps do not have a long enough wheelbase for the longer, five-speed transmissions.

These are strong transmissions, and full Size Jeeps such as Wagoneers, J-Trucks, etc. are conversion candidates for them unless used for more aggressive driving or heavy work situations.

Compatible Engines

Nearly all GM Generation I-III engines are compatible with this conversion, including Chevrolet Small Blocks, Gen III+ V8's, Chevrolet V6's and Chevrolet I6 engines. Also, Buick, Olds, Pontiac, and other GM engines are compatible with this adapter assembly if you have a standard shift classic GM bellhousing and flywheel for your engine. Even some of the front wheel drive and unique engines could be made to work with this adapter using certain factory or aftermarket bellhousings sharing this common bellhousing / transmission bolt pattern.

GM Bellhousings

Chevrolet Muncie Saginaw Bellhousings

The classic Chevrolet bellhousing, with the four-bolt rear pattern. Buick, Olds, Pontiac and other bellhousings with the same rear face are equally compatible.

your GM bellhousings will typically feature either a 4-11/16" rear face bore or a 5-1/8" rear face bore, the latter typically only from Chevy / GM trucks from 1968-1991. Our adapter will works natively with the smaller bore bellhousing and with the larger bore bellhousing if you choose the 5-1/8" press-on spacer ring. If you are unsure of your bellhousing bore, buy the ring and return it after your build if it turns out you don't require it. See Related Products, below.

Clutch Assembly

Because of the 1-1/8" x 10 spline configuration of these transmissions, use an off-the-shelf GM clutch kit (pressure plate & disc) with this conversion.

Be aware of the following clutch configurations - see Related Products below for more information:

  • 153 tooth classic flywheels typically use a 10-1/2" clutch assembly
  • 168 tooth classic flywheels typically use a 11" or 12" clutch assembly
  • Gen III+ engines should use a taller aftermarket flywheel that normalizes the clutch kit to a classic 168 tooth style

The pilot bushing included with most clutch kits will not be compatible with the pilot tip diameter of these transmissions. See Related Products below to select your proper pilot bushing.

Clutch Release

The factory style master cylinder can be retained. The hydraulic line and slave cylinder need to be changed over to a system which is compatible with the GM bellhousing. Novak's #HCR Series slave cylinder kits are ideal for this situation. We also provide a hydraulic line and brass fitting which allows the conversion from the factory hose. See Related Products, below.

Clutch release bearings need to be a GM compatible unit. Because of the various heights of pressure plate fingers, consider Novak's adjustable throwout bearing assembly, available in Related Products, below.

For more theory and in-depth discussion about clutch systems, see Novak's Guide to Clutches, Linkages and Bellhousings.

Transmission Versions

NV3550 TransmissionAll versions of the NV3550 are compatible. However, all NV3550's will require a minor modification to their input bearing retainer.

Related Products


Bushing, pilot, GM Gen. I-III (1955-2000) cranks to Jeep T14, T15, T18 (1972-1975) & AX15 (1992-1999

This pilot bushing fits classic GM cranks and matches the pilot tip of the NV3550 as found in 2000-2004 Jeeps.

Jeep T14 to GM pilot bushing

Bushing, pilot, GM Gen III (2001- ) cranks to Jeep T14, T15, T18 (1972-1975), AX15 (1992-1999), 3550

This pilot bushing fits in GM Gen III+ Vortec / LS cranks and matches the pilot tip of the NV3550 as found in 2000-2004 Jeeps.

Ring, sizing, precision, 4-11/16” GM bearing retainers to 5-1/8” bore bellhousings

Press this ring onto the retainer of the Novak adapter if you have the 5-1/8" truck bellhousing as found on so many GM engines from 1968-1991. If you are unsure of the bore diameter of your Chevy bellhousing, you can buy this ring and return it if unused.

Adjustable clutch release throwout bearing

Bearing, clutch release, throwout, Novak adjustable, GM version

This release bearing assembly uses a telescoping and locking design which spans the range of shortest to longest GM throwout beareings that were ever available. It is helpful if the installer wants a one-and-done solution that avoids trips to the parts store, and sometimes for bearing heights that just aren't made anymore by GM or the aftermarket.

Hydraulic clutch retrofit kit for GM bellhousings, #HCR

Novak's popular HCR series clutch release slave kits will bolt onto your existing GM (Chevy or Buick) bellhousing and provide you with the foundation for a strong, smooth, adjustable, servicable and durable clutch release system. See the details and options here.

Hydraulic release master kit for Jeeps

Assembly, Clutch line, stainless braided, 3AN female ends, includes fittings, 32" length

This durable hose will join your master cylinder to the Novak hydraulic slave kit.

Hydraulic release master kit for Jeeps

Kit, hydraulic clutch release line adapter, late style, short (typ. TJ) 3AN male

This brass fitting joins the proprietary factory TJ / LJ master cylinder to our standard stainless wrapped poly hose, to make it compatible with the Novak #HCR series clutch release kit. O-rings are included.

Adjustable clutch arm pivot

Pivot, ball stud, clutch release arm, adjustable, GM bellhousings

This handy clutch release pivot stud is what we reach for when setting up a clutch system. Unlike factory GM pivots, it can adjust for better clutch arm geometry and clearance with the bellhousing window.

GM LS Vortec Bellhousing

Kit, bellhousing, GM Gen III engines to Muncie / Saginaw transmissions, 4-1/16” bore. 12” clutch

Kit, bellhousing, GM Gen III+ engines to Muncie / Saginaw transmissions, 4-1/16” bore, compatible with 168 tooth flywheel & 12” clutch. Includes the pivot stud, release fork boot and flywheel cover.

GM Chevy Bellhousing

Kit, bellhousing, Chevy 90 degree engines to GM transmissions, 4-11/16 bore, 12” clutch, 168 tooth f

Kit, bellhousing, Chevy 90 degree engines to GM transmissions, 4-11/16 bore, 12” clutch, 168 tooth flywheel, enhanced casting. Includes the pivot stud, release fork boot and flywheel cover.

Extended depth flywheel for GM engines

Flywheel, GM Gen III/IV V8 engines, 168 tooth, offset version, billet, SFI, 35 lb, for standardized

This flywheel standardizes LS engines so they can use standard off-the-shelf clutch kits like earlier Chevrolet engines. Their extended height makes up for the shorter cranks in most LS / Vortec / Gen III+ engines. Bolts and clutch kit available, adjacent.

Bolts for GM engine flywheel to crank

Bolts, 11mm x 1.5mm, LS engine crank, extended length, 4.8, 5.3, 5.7, 6.0L, LS1, LS6

These bolts will fasten your flywheel to your GM Gen III+ crank. They are high-strength alloy and feature the unique GM thread pitch.

GM clutch kit

Kit, clutch, GM & Chev. V8, 12”, 10 spline x 1-1/8”, includes pressure plate, disc, alignment tool

This kit is compatible with the Novak LS flywheel (adjacent) and classic factory Small & Big Block 168 tooth flywheels for most Chevy engines. It features a pressure plate with great holding power but civilized release pressure.

GM clutch kit

Kit, clutch, GM & Chevy 10-1/2”, 10 spline x 1-1/8”spline, incl pressure plate, disc, alignment tool

This kit is compatible with classic factory Small Block 153 tooth flywheels for many Chevy engines. It features a pressure plate with good holding power but civilized release pressure.

GM clutch kit

Kit, clutch, GM & Chev. V8, 11”, 10 spline x 1-1/8”, includes pressure plate, disc, alignment tool

This kit is compatible with classic factory Small Block 168 tooth flywheels for many Chevy engines. It features a pressure plate with great holding power but civilized release pressure.

AX15 & NV3550 Rear Mount

Kit RMAX15, mount, rear, AX15 and NV3550 transmissions, universal & adjustable

The AX15 and NV3550 feature a threaded base for support and isolation of the transmission and transfer case. Factory style isolator mounts are difficult in situations other than as a direct factory replacement. Novak's universal style rear mount is easy to affix to a variety of Jeep crossmembers, is strong and highly adjustable.Recommended for retrofit builds.

Adapting NV3550 transmissions to Jeep Dana 300 transfer cases

Kit 153, adapting the AX15, AX5, NV3550 or AW4 to the Jeep Model 300 transfer case

This adapter kit is for those fitting an NV3550 into a Jeep with the Dana 300 transfer case. Read more about it here.

Adapting NV3550 transmissions to Jeep Dana 18 & 20 transfer cases

Kit 152, adapting the AX15, AX5, NV3550 or AW4 to the Jeep Models 18 & 20 transfer cases

This adapter kit is for those fitting an NV3550 into a Jeep with the Dana 18 or 20 transfer cases. Read more about it here.


Transfer Case Shifter Kits

Many of these transmission retrofits end up in earlier Jeeps and they often require a modified transfer case shifter kit. For the Jeep Dana 300, we recommend the Adjustable Length twin stick kit with these transmissions. The TX300 can be used but is positioned further back and requires modification to the shifters to clear as well as the pan and tub.

Installation Requirements

Tools

A drill, 33/64” bit, and various smaller bits are required, in addition to typical mechanic's hand tools.

NV3550 Installation Caveat

gm_to_3550_adapter_quarterNote that NV3550 transmissions have a shift rail boss that protrudes through the adapter, and will require that the bellhousing be milled for clearance. The adapter can be used as a template to mark for this operation.

Placement

Transmission placement is largely determined by engine location. It is not necessary in typical conversions to change the engine position. Setting the powertrain to the proper factory or conversion pitch angle - usually tilted down ~5 degrees (3-7 acceptable) is recommended.

Engines & Engine Mounting

GM Engine Mounts for JeepsNovak engine mounts are available to ease the installation of your GM V6 or V8 engine. Novak has engines mounts for most Chevy, Buick and GM Gen III+ V8's.

Novak's engine mounts, feature vibration dampening, superior strength and useful adjustability - adjustable even after the engine is installed. The design, strength, and affordability of our mounts are second to none.

Engine placement in these Jeeps should consider the following points:

  • Left-right offset location is similar to factory at ~1-1/4" to the driver's side
  • Avoid installing the engine too low (axle clearance and other issues)
  • Avoid installing the engine too high (transmission tunnel interference, etc.)
  • Set your engine to 4-7 degrees of tilt rearwards, like the factory engine & powertrain
  • It is usually best that Chevy and Gen III+ V8 engines install approximately 3" further forward, using the back of the engine block face as the datum
  • When mocking up your engine installation location, pay special attention to radiator and fan clearance.
  • Firewall modifications are not expected.

Since TJ Jeeps featuring the AX15 & NV3550 transmissions have higher hood clearance, clearance for classic Small Block and high Vortec (truck style) intakes and accessories is not a problem. Same for CJ's and Trucks that are getting these transmission / engine combos as retrofits. However, XJ / MJ Jeeps have low hoods and will require the use of lower car intakes and accessory packages.

Novak Gen III+ engine mounts for TJ, XJ, & '76-'86 CJs will remove any guesswork from the engine installation location as they are predetermined for the best location and engine clearance margins.

Driveshafts

Driveshaft length changes may be required. Chevy engines (with their rear distributors) can install around 3" further forward than AMC engines. It is also recommended that LS family engines be installed 3" further forward than the factory block (using the back face of the block as the datum point) for exhaust clearance, firewall access, etc.

Because of the engine placement and transfer case SYE kits are frequently installed with many of these conversions, you may end up with a longer rear driveshaft (very desirable for lifted Jeeps) and a shorter front driveshaft.

Some installers, concerned about the expense of new or modified driveshafts, attempt to let the existing driveshafts dictate engine, transmission and transfer case location, often to the detriment of the project. Our recommendation is to prioritize the correct position of drivetrain components over saving a few dollars which is usually regretted in the long run with compromised positioning.

Jeeps that require extensive travel or specialty-built driveshafts have this option available through several fabricators across the nation. These are normally specified after placement of the new transmission and measured at vehicle ride height. As the rear driveline gets shorter, it is often advantageous to us a Double Cardan or “CV style” rear shaft with the correct geometry at the axle to minimize vibrations and possible binding.

Axles

Use of factory axles is completely acceptable with this conversion. Axle upgrades are not necessary, but they may be chosen for reasons external to this transmission upgrade.

Also See