During the 1970s America was subjected to a large scale Arab oil embargo. American consumers experienced long lines at gas stations and limits on gasoline purchases. Rising gas prices created an immediate desire for vehicles offering better fuel economy. Ford was one of the first U.S auto manufacturers to actively pursue offering a factory OEM overdrive transmission. The result was a manual four speed transmission where fourth gear was an overdrive. Ford introduced the transmission with an advertising campaign touting how their new overdrive transmission was perfect for both “Town and Country”. The new transmission would come to be known as the “Town and Country Overdrive Transmission” or “T&C-O.D”. The transmission would also garner other pseudonyms like: Top Loader 4 speed O.D, RUG, RTS, and T-170.
The “T&C- O.D.” transmission was first introduced during the late 70’s in Ford passenger cars like Granadas, Fairmonts and Monarchs. This “car version” of the transmission was commonly referred to as the “RUG”. There are several ways to identify this transmission. The “RUG” tailhousing section frequently has casting numbers starting with D7, D8, and D9. We have also seen some transmission castings stamped "Orion." The early version of the transmission is a cast iron case. An aluminum case would be introduced later. The case is 10-1/4" long and Weighs 78lbs. Casting numbers of 2603606 or 2603729 are commonly found on the case. The “RUG” model has the shift levers on the left hand side of the main case. When using this “RUG” version for conversions, additional items like shift rods and a Hurst shifter will be required.
The “RUG” shares a close resemblance to the Ford 4 speed toploader transmission. The design of the “RUG” is often thought to be a Top Loader with an overdrive 4 gear. In actuality, The “RUG” overdrive gear is where 3rd gear is in the transmission. This was accomplished by flipping the shift lever arm upside down. A noticeable bulge protrusion is apparent on the passenger side of the case of the “RUG”. The bulge is approximately an inch and a half wide. This was to allow for the overdrive gear to fit in the case. This protrusion can offer salvage yard searchers an easy way to identify this transmission. It should be noted that the “RUG” also have a lug cast on the tail shaft to allow for a driveshaft vibration dampener to be used. Another key identification difference between the “Top Loader” and the “T&C-O.D.” is the front bolt pattern. The “T&C-O.D.” only has the standard Ford “butterfly” bolt pattern. The “Top Loader” has an 8 bolt pattern to accommodate both the “butterfly” and the earlier pre-1965 Ford bolt pattern.
*Notice bulge on “T&C O.D” (bottom transmission) Ford 4 speed top loader (top transmission)
*Notice the Ford 4 bolt “Butterfly” pattern on the “T&C- O.D.”, the “4speed Top Loader” (on right) has an 8 bolt pattern to accommodate the earlier pre-1965 Ford bolt pattern
Another version of the “T&C- O.D.” transmission was found in Ford Trucks, Broncos, and Econoline Vans. This version of the transmission had an aluminum case, aluminum shift tower, and a top shift control cane shifter. These transmissions were more commonly referred to as “RTS”. The “RTS” is largely considered the “Truck” version of the “T&C- O.D.” The transmission would also bolster a larger rear bearing than the car version. This transmission commonly was stamped with a casting #2605275. The transmission was manufactured in Mexico by the Tremec Corp under the name “T-170”. The “RTS” was the first predecessor of the successful T-170 series of the transmission that would include the popular Jeep T176.
*RTS transmission with Ford truck tailhousing
*RTS Casting #
Gear Ratios
| Truck | |
| 1st Gear | 3.25:1 |
| 2nd Gear | 1.92:1 |
| 3rd Gear | 1.00:1 |
| 4th Gear | 0.78:1 |
| Reverse | 3.25:1 |
| Car | |
| 1st Gear | 3.29:1 |
| 2nd Gear | 1.84:1 |
| 3rd Gear | 1.00:1 |
| 4th Gear | 0.81:1 |
| Reverse | 3.25:1 |
The “T&C-O.D” transmission started the wheels in motion for manual transmissions with overdrive. There had been a number of overdrives on the market all throughout the 50s and 60s, but they were essentially 3 speed transmissions with an added overdrive. The “T&C-O.D” laid the groundwork for the evolution of manual overdrive transmissions. This would later include the introduction of heavy duty 5 speeds in the early 1990’s.
Conversions:
Why would someone select the “T&C-O.D.” transmission for a conversion? There are certainly more modern overdrive transmissions like the NV4500. The problem lies in length. Five speed transmissions are typically long and therefore just don’t fit well in a small wheel base vehicle. This is where the “T&C-O.D.” really shines. The “T&C-O.D.” makes an excellent candidate for short wheel base vehicles. The transmission offers overdrive while retaining an acceptable rear driveshaft length. The 1972-1979 CJ5 Jeeps are a prime candidate for this transmission. Since these vehicles use the Dana 20 transfer case, The Saturn overdrive is not an option. Although the transmission does not have a granny gear, it is still similarly geared to many Jeep transmissions like the T15 and T-150. The transmission is also well suited for older Broncos who seek a better option than the “3 speed top loader”.