The Novak Guide to the

Borg-Warner T18 & T19 Transmissions

The T18 is a renowned, heavy-duty truck transmission designed for and used in ½, 3/4 and 1+ ton trucks. They are found in Ford, Jeep and IH trucks. The T18 is the improved successor to the T98 transmission. The T18 was made for automotive use by Borg-Warner Gear from 1965 to 1991.

The T18 is also a popular industrial transmission, being used in drilling, mining, lift trucks and other important industries. Industrial T18's have been made by Borg Warner, Tremec, Allied Gear, Gear Wizzard and now Novak.


The T18 is a top loaded, top shifting truck style transmission. The Ford and some Jeep T18s have a very low compound gear at 6.32:1 and as such it is a popular choice for those wanting a very low crawling gear. T19 versions offer a 6.32:1 (IH), 5:1 or 4:1 (Ford) low gear.

The T18 is synchronized in the second through fourth gears. All gears are helically cut except first and reverse, which are spur gears. T19s are fully synchronized in all gears and feature all helically cut gears.

The T18 transmission is 11.9" long and features a cast iron top cover that is retained by six bolts. The T18 case is of cast iron. The case itself is unusually narrow for a heavy-duty gearbox, and features mild ribbing for strength. The case and top cover are both cast iron, with the top cover being retained by six bolts.

Top Cover Shift Control Housings

T18 top cover shifter later version
The later style shift control housing
with the suspended aluminum forks

For its first several years in production, the T18 used the same case and top cover as its predecessor, the T98. As such, it may be required to pop the top cover and verify by internal features. Top cover castings that say T98 may actually well be a T18, since they used the same case castings.

There are two different versions of shift control housings. The 1966-1978 versions hung two cast iron shift forks into the case, with the reverse fork itself pivoting on the side of the case. These earlier T18’s have reverse gear over to the right and up by third gear. In 1979, the reverse shifter fork was moved from the side of the case into the top cover instead and all three forks were changed and made with die-cast aluminum. This later T18 has reverse gear shift pattern over to the right and down by fourth gear.

The earlier shifter versions are readily obvious by the presence of a cast-in boss on the rear, left flank of the transmission. Later Borg-Warner casting tooling was updated and omitted this boss (as in the image, above right).

Applications - Automotive: Jeep, IH & Ford

Jeep T18


Jeep T18s typically have 6-spline and threaded end output shafts onto which the Dana transfer case gear installs directly. 1980 and later Jeep T18s (found in J-Trucks only) featured a 31-spline output shaft that - like the Ford versions - was excessively long for installation into any short wheelbase Jeep.

Jeep released 12 known versions of the T18 transmissions from 1966 and 1984, with the greatest variations being in input shaft configurations and gearing. The battle of working with these is compounded if you did not actually witness the transmission's removal from the donor vehicle.

All Jeep T18's locate their PTO port on the driver's side.

Generally, most CJ T18's from 1972 to 1975 had the close-ratio, fitted with a front adapter plate in cast iron to the AMC bellhousing. These transmissions had the narrow ratio gearing (4.02:1 first gear). These 1972-1975 Jeep CJ T18's adapt to GM Engines with our #1415 kit.

1976 was a crossover year for the Jeep CJ T18, featuring either the 4.02 or 6:32 first gear and no front adapter as previously. Both these and all CJ T18's through 1979 had the shortest of the Jeep input shafts, measuring 7.43" of stickout.

All Jeep CJ's from 1977 to 1979 had wide-ratio T18 with the 6.32:1 first gear. No front adapter plate is present on these models. 1976-1979 T18 transmissions can be adapted to GM V6 or V8 by use of a T18 adapter kit that we manufacture, kit #1879. Jeep CJ T18's from 1976-1978 may be cast with #13-01-097-907.

The 1979 Jeep CJ T18 is similar to the 1976-1978 versions, except that it features a wider front bearing and a different top cover with aluminum shift forks and a different shift pattern with reverse gear being over to the right and down. These T18's may have a case casting number of 13-01-065-904 and a top cover casting of #13-01-065-906.

As a general rule, all FSJ T18's featured varying lengths of input shafts - all too long for installation into short wheelbased Jeeps. These were fitted with a variety of factory adapters and deeper bellhousings to accomodate the deeper bulkheads of these larger Jeeps. We get many calls from individuals attempting to adapt these versions into CJ Jeeps - many of them being sold under the unscrupulous pretense that they are inexpensive and direct replacements. Individuals get caught in often fruitless salvage searches for the rarest of the Jeep T18 input shafts and bearing retainers in an attempt to make the project succeed. As a solution for wide ratio (6.32:1 first gear) Jeep T18's, we offer a new input shaft and retainer assembly, kit #T18-ISK. There is currently no solution for the narrow ratio (4.02:1) Jeep T18's.

Jeep & IH T18 rear bolt pattern, 1966-1979

Casting numbers commonly found on Jeep truck T18's are #13-01-192, #13-01-193, #13-01-209, #13-01-210, which are typically the close ratio versions of the Jeep T18 transmission.

Adapting Jeep T18's to GM Engines

Certain versions of the Jeep T18 can be married to GM engines.Read more about this process here.

IH T18

The International Harvester T18 was similar to the Jeep T18 in terms of its mainshaft / output shafts being six-spline, and the rear case bolt pattern. The IH T18 was available only in three versions:

  • T18, wide-ratio 6.32:1 version, same as the wide-ratio Ford & Jeep T18's
  • T18A, close-ratio version, with 4.02, 2.41, 1.41, 1.0 ratios
  • T18C, close-ratio version, with 4.02, 2.41, 1.52, 1.0 ratios

This transmission is a good unit, but not recommended for Jeep conversions due to its unique input shaft and front, stud-mounted style front face.

IH T18's we've seen in our collection locate their PTO port on the driver's side, and according to IH literature, could have dual PTO ports.

Ford T18

The Ford T18 has a 1-1/16" diameter, ten spline input shaft that has a stick-out of 6-1/2" from the front face of the transmission. The pilot tip of the transmission measures ~17mm. The front bearing retainer flange measures ~4.85" and the bearing retainer tube is 1.43" in diameter. The front bolt pattern is the symmetrical Ford "butterfly" pattern; roughly 8-1/2" wide by 6-5/16" tall. The input shaft stick-out length is 6-1/2". Checking these dimensions will verify that the transmission is a 1966 or newer model, precluding it from being the T98.

The Ford T18 & T19 2wd or 4wd rear bolt pattern. This is also the Jeep T18 pattern from 1980-1986

The Ford versions can also be identified by its numbers cast into the driver's side of the case, commonly "T18-1E" for earlier units and "13-01" for later units. From 1966 until 1978, many T18s used a T98 shifter assembly. 1979 and newer T18s used a three fork shift cover assembly that shifts reverse gear directly. Because of this, reverse location is on the opposite side of neutral than the earlier version ('66 to '78). Earlier versions reverse gears shifts over and up - later versions shift over and down.

The Ford T18 features a power-take-off (PTO) port on the passenger side of the case.

The last years of the T18 featured a direct-drive (4th gear) switch to signal a lean or cruise mode operation to the Engine Control Module (ECM). Later Ford T18's and T19's used an aluminum front bearing retainer in lieu of the earlier and longer wearing cast iron retainers. We can supply new cast iron retainers to replace these.

If you can locate the production ID tag on your Ford T18 top cover, you will find a lettering code akin to “D7T3...”. This may help identify the year of transmission, as Ford uses the first letter to designate the decade (C=’60s, D=’70s, etc.) and the year is called out by the second digit.

A certainly uncommon version of the Ford T18 was the T18B, as provided in diesel trucks from 1967-1972, featuring higher gear ratios in 1st thru 3rd gears (4.32, 2.26, 1.51). This transmission will be rarely encountered, but be aware of the possibility.

Conversion T18's, Ford vs. Jeep

The Ford T18's are clearly the best conversion choices in that they are far more standardized, easier to find and often more affordable. Replacement parts (namely, gears and shafts) for the Ford T18 are easily less expensive. Many, if not most, of the Jeep specific gears are no longer produced, making them painfully problematic to own if anything ever goes wrong or if parts interchangeability is required for a specific, non-standard adaptation.

Ford & Scout T19's

Similar to the T18 in appearance and build is the T19. This four-speed transmission is different from the T18 and others in that it usually features taller gearing and a synchronized first gear. It was introduced in Ford trucks in the 1968 model year.

Three gearing options were available for the Ford T19. The T19 was available with a 6.32:1 first gear. These were only in rarer Ford 500-800 series HD trucks. The very most common T19 available in Ford applications was the T19A with the 4:02:1 first gear ratio. For two years (documented from 1983-1986+) there was a Ford T19 option with a 5.11:1 first gear. All ratios listed had a synchronized first.

We've learned that the 1983 to 1986 Ford T19's, as installed behind the 460 and diesel typically had the 4.02:1 first gear in a 2wd application, or a diesel 4wd application. However, 5.11 versions are reported also for these. The 460 4wd truck got the 6.32:1 first gear, purportedly from 1983 to 1986 F250's.

The T19 transmissions are equipped with dual PTO ports. An individual may find the cast numbers of 13-09-065-911 or 13-09-065-905 in Ford T19's.

T19 Specifications

The IH Scout T19 was available from 1975 to 1980 with close and wide ratio options. Individuals may encounter a casting number 13-09-065-905. Like for the IH T18, the T19 had a unique case and input shaft that make most Jeep conversions impractically expensive.

Best Truck Four Speed Ever?

In terms of design and engineering, the T19 is agreed by many to be the greatest truck four-speed ever built. They perform great, wear well, rebuild nicely and are able to transmit significant torque and horsepower in a compact package. The T19 was the upgrade option by manufacturers and they are sought after by those in the know.

Transfer Case Adaptability

All Ford versions of the T18 are automatically compatible with Novak adapter assemblies and these transmissions make for excellent conversions due to their adaptability into most Jeeps. Both 2wd and 4wd versions of the T18 can be used equally well, and there are no inherent advantages to either one once you have installed our adapter assembly.

The Ford T18 can be adapted to the popular Jeep (and many IH) transfer cases, including the:


A turn-key T18, professionally built, adapted or OEM style and delivered to your door - ready for a variety of engines and Jeep transfer cases. Read more...

The Jeep and most IH T18's can be adapted to the Jeep Dana 300 and to the New Process transfer cases with equal ease.

Bellhousing Adaptability

Ford Engines

As the reader will conclude, the Ford T18 will marry directly to Ford Small Block style bellhousing. These were common from the late 1960's up through 1991 with the Ford Windsor and other bellhousings respective to the engine you're working with.

AMC Jeep Engines

The Ford T18 is also an excellent candidate for AMC Jeep bellhousings made from 1976 to 1986 that were married to the T150, T18 and T176 transmissions, or otherwise have an available bellhousing bolt pattern of 8-1/2" wide by 6-5/16" tall. They are readily compatible with these engines and bellhousings, and need only a custom pilot bushing. For more details, see Adapting Ford Transmissions to AMC Bellhousings for details.

The 4.0L Jeep I6 (both Renix and Mopar systems) is adaptable using the same method as above, with the addition of installing a Crank Position Sensor (CPS) into the aforementioned bellhousing. This is a service that we provide affordably and in quick turnaround.

GM Engines

The Ford T18 has two extra undrilled ears cast into the front face of the transmission case. This is important if you intend to run it behind a GM bellhousing. The transmission having these extra undrilled ears will greatly simplify its use with GM engines. The T19 does not have these extra ears, however, Novak's #F2GM bracket set solves for this.

For more details, see Adapting Ford Transmissions to GM Bellhousings.

Rebuilding the T18

When filling your T18 / T19 with gear oil, we recommend that you select a conventional mineral oil or a para-synthetic in lieu of a full synthetic oil. Properly assembled manual gearboxes do not have the thermal strains seen by combustion engines or hypoid gears. Synthetic fluid in these gearboxes, while not harmful, is probably an economic waste.

Hypoid gear oil is sulphurized higher than transmission oil and can be mildly corrosive to the non-ferrous alloys used for synchros, bushings and thrust washers in these transmissions.

An 80W-90, API-GL5 or MT-1 rated fluid is very good. Some claim faster shifts from using a 50W engine oil in their transmission and we do not consider this to be contraindicated unless you operate your vehicle in a very warm environment.

The T18 and T19 are so worth the rebuild. Many shadetree mechanics do outstanding rebuilds if they have access to a press, snap ring pliers and bearing pullers. Many choose to do a full rebuild during the adaptation process, and our instruction guides feature all the details, diagrams, pics and tricks required to do professional level work.

Rebuild and repair parts for the T-18 transmission