Transmission Swap, Tranny Install, and Truck Parts

The NV4500 is an extremely strong five-speed transmission used in late-model Chevy and Dodge trucks. While the internals of the tranny for these two trucks are the same, the exterior bolt patterns, input shafts, and output shafts are different, so be sure to research your proposed swap to see which version of the tranny is preferable. It’s ultra-deep First gear ratio of either 6.34:1 or 5.61:1 (depending on the tranny) combined with its 0.73:1 Overdrive make it one of the most sought-after manuals for swapping today. Thanks to companies such as Advance Adapters and JB Conversions, these trannies can be adapted to practically application. (Photo Courtesy Advance Adapters)
The NV4500 is an extremely strong five-speed transmission used in late-model Chevy and Dod

The SM465 is a four-speed manual that was used in Chevy trucks from the late 1960s until it was replaced by the Getrag and NV4500 five-speeds in the early 1990s. Because of its long production run, it’s plentiful and cheap in salvage yards compared to other manuals. The SM465 offers bulletproof construction, a deep 6.55:1 nonsynchronized First gear ratio, and excellent reliability, all of which are excellent traits for a 4x4. However, it has no Overdrive, so geargrinders looking for both a low First gear and an Overdrive may want to consider an NV4500.
The SM465 is a four-speed manual that was used in Chevy trucks from the late 1960s until i
The TH700-R4 is a four-speed automatic with a 0.70 Overdrive and a 3.06:1 First. While it was initially thought to be weak and had high failure rates during the first few years of production, it has since been significantly improved and can survive under severe applications. These days, a 700-R4 is arguably the most popular automatic swap candidate.
The TH700-R4 is a four-speed automatic with a 0.70 Overdrive and a 3.06:1 First. While it

The TH350 and its heavy-duty brother the TH400 have excellent reputations for strength and reliability. The TH350 can be built to withstand just about any horsepower you can throw at it, and the TH400 is a stout performer right out of the box that was used in many heavy-duty applications. A TH350 is plentiful and cheap in practically any wrecking yard, and it was used behind many different Chevy transfer cases. The TH400 may be more expensive and the 4x4 versions are harder to find, but its bulletproof construction makes for an excellent candidate in a severe-duty application.
The TH350 and its heavy-duty brother the TH400 have excellent reputations for strength and
The T18 is yet another bulletproof four-speed manual, and versions of it were used in Jeep, Ford, and Scout applications. There are many varieties of the Jeep T18 and not all of them are equipped with a granny-low First gear. The Ford T18 shares many external similarities with the NP435 (shown), and the two transmissions were used for many years under fullsize trucks. The majority of the 4x4 Ford T18s have a 6.32:1 First gear ratio. T18s are plentiful in salvage yards, but all the variations and its physical similarity to other transmissions can make it difficult to spot.
The T18 is yet another bulletproof four-speed manual, and versions of it were used in Jeep

Most automatic transmissions have fixed, nonremovable bellhousings. As a result, most adapters for autos are simply a thin plate sandwiched between the back of the engine and the face of the bellhousing. These plates space back the tranny slightly, so a special flexplate with a spacer is normally required to make up the distance. Some of these adapter plates have provisions for the stock starter for the engine or transmission, so be sure to know which one you need to avoid hold-ups later.
Most automatic transmissions have fixed, nonremovable bellhousings. As a result, most adap
There are two different ways manual trannies can be adapted to engines. Since most bellhousings on manuals are removable, some adapters call for retaining the original tranny’s bellhousing and using a plate to adapt the bellhousing to the new transmission. This plate can vary in thickness to compensate for the length of the new tranny’s input shaft and to adjust the overall length of the transmission assembly. Other tranny conversions require using a whole new bellhousing that’s specially made for the application. The plate-style adapters are usually less expensive and cause fewer clutch linkage problems.
There are two different ways manual trannies can be adapted to engines. Since most bellhou

Some adapters utilize the stock tailhousings and adapt it to the new tranny with a plate, but many have a whole new custom tailhousing that incorporates a mounting foot for the tranny, a place to relocate the transfer case linkage, and the shortest possible overall length of the tranny assembly. Keep in mind that the tranny must be disassembled to install a new tailshaft in some cases, which is more expensive than an adapter that utilizes a spud shaft. However, using a new tailhousing rather than a spud shaft provides a stronger link.
Some adapters utilize the stock tailhousings and adapt it to the new tranny with a plate,
A manual tranny swap usually needs special clutch components in order to work properly. A clutch disc from one application might be combined with the pressure plate from another, and a special pilot bushing is sometimes needed to properly index the input shaft. Whenever possible, the stock clutch linkage for the vehicle is retained, but custom rods and pivots are often needed to make the linkage work properly.
A manual tranny swap usually needs special clutch components in order to work properly. A

In the 4x4 world, gearing is the stuff dreams are made of. Gearing can compensate for an anemic powerplant, give a rockcrawler greater crawling ability, provide the low-end grunt needed to get a heavy load moving, and enable the engine to lope at freeway speeds for better fuel economy. One of the best ways to obtain all of the above in a vehicle that lacks any of these capabilities is to swap in a different tranny. We’re going to take a look at some of the parts, procedures, and requirements for swapping five of the most popular trannies--the NV4500, the T18, the SM465, the TH350 auto and it’s heavy-duty brother the TH400, and the TH700-R4 into Chevys, Fords, and Jeeps.

If you need more information on the specs of these trannies and why they’re popular, check out past issues of 4-Wheel & Off-Road. We’ve broken down this article into three vehicle-make sections and then listed the specifics for each tranny within the section, so there’s no need to wade through a pile of info on other vehicles that you don’t care about. You’ll also find that most of the information in the following paragraphs consists of what parts and adapters are needed for various swaps, what type of tranny to look for, and all the basic stuff needed to physically bolt a nonstock tranny between an engine and a transfer case.

In some cases, there’s not a lot of information on all the auxiliary but still vital parts needed to complete a swap, such as the clutch linkage, the crossmember alterations, and the transfer case shifter control mods and so on. Why? We could say there’s no way we could fit all that information in the limited space here (which is true), but the main reason is that, due to the different vehicle and drivetrain combinations, virtually every tranny swap is different. Each person that attempts a swap will run into problems or concerns that are unique to his or her application, and these will need to be addressed on an individual basis.

Sometimes a company such as Advance offers items to address specific situations, and whenever possible we include this information in the story. But in many cases it’s up to the swapper to make all the parts and pieces work. Therefore, understand what you’re getting into before you start, and we’d strongly recommend having a fair amount of fabricating and adapting experience under your belt or a good support group--such as Advance Adapter’s tech line and a local expert--before you begin. Special thanks to Chris Hansen at Advance Adapters and John White at JB Conversions for sharing with us their invaluable knowledge and expertise.