Torqueflite 904/999
The 904/999 Torqueflite transmission is legendary among Jeep enthusiasts. The transmission was used for over 23 years which makes it one of longest used transmission in the history of Jeep.
History
The History of the Torqueflite 999 dates back several decades before Jeep introduced the transmission in 1980. After the successful launch of the 727 Torquelfite back in the late 1950's, Chrysler embarked on designing a scaled down version of the Torqueflite 727. This was needed due to the tendency of the 727 robbing some of the power from the engine. The new scaled down version would be known as the Torqueflite A-904 and it would find its way initially behind the Slant 6. Although not as strong as the 727, the A-904 transmission was deemed a complete success.
AMC first started using the 904/999 Torqueflite transmissions in their passenger cars as early as 1972. AMC however was locked into a long stemming contract with GM to supply Turbo 400 transmissions in the Jeeps. Jeep continued to use the TH400 until their contract with GM ended in 1979. At that time, Jeep decided to sign a contract with Chrysler to supply a full series of Torqueflite transmissions. The Torqueflite 904/999 series of transmissions were used in Jeep CJ, MJ and XJ models. The full size Jeeps used the more robust 727 Torqueflite transmissions.
Nomenclature
In order to best describe the differences of the Jeep 904/999 Torqueflite transmissions. Jeep renamed the different series of Torqueflite transmissions to better define their differences. Although the renaming did not occur until 1991. The coding system better defines torque capacity, drive type, axle orientation, and shift control system. The new coding system designates 4 characters to indicate the orientation of the transmission
|
Forward speeds |
Torque rating |
Drive type |
Control system |
|
3 or 4 |
1 (low) to 9 (high) |
R (Rear wheel) T (Transverse) A (All-wheel) |
H (Hydraulic) E (Electronic) |
Torqueflite 904 (30RH)
The Jeep 904 transmission was 1st used by Jeep behind the 4 cylinder CJ starting in 1980. From 1980 to 1982 this transmission was used behind the Iron Duke engine. The Iron Duke application was extremely rare, as even the 1980 Jeep service manual does not acknowledge its' existence. The Iron Duke engine had the same bolt pattern as a Chevy V8. This obviously sounds alluring for a V8 conversion; however, we have found customers who have attempted this conversion have run into complex issues dealing with flexplate, torque converter and starter issues. This Iron Duke/ Torqueflite combination was heavily used in U.S. Postal DJ Jeeps.
In 1983 Jeep retired the Iron Duke and introduced the AMC 4cylinder. The new engine had a different bolt pattern and with it the 904 transmission bolt pattern was also changed. The AMC 2.5/904 shares the same bolt pattern as the 60-degree GM bolt pattern. Jeep utilized this bolt pattern not only for their AMC 4cyl but also the Chevy 2.8 that Jeep used in their down sized XJ Cherokee. Advance Adapters does not offer any engine adapters for these versions of the 904/30RH
Torqueflite 999 (32RH)
The Jeep 999 transmission was 1st used in 1980 behind the AMC 258 inline 6 motor. The 999 has stronger holding power versus the 904. This is due to the planetary gear stationary and double-wrap rear band. The 999 also uses more clutch packs and a larger planetary. This is obviously due to the increased torque capacity of the 4.0L engine. Overall, the 999 very capable behind the 258 and can handle most V8 applications. We have found the 999 was also used in rock buggies running heavy horse power V8 engines. Chris Durham is one competitor that ran an upgraded 999 transmission with a V8.
The 999 were used exclusively behind the Dana 300 transfer case in 1980-1986 CJ Jeeps. Later Wranglers would use the NP231 transfer case. Both of these transfer cases utilized the round circular 6 bolt pattern still in use today. The output shaft of the 999 always used a 23 spline shaft and a somewhat long transfer case adapter. Dana 300 transfer cases always had the front drive shaft located on the passenger side of the vehicle. Jeep Wrangler NP231 transfer cases always had the front drive shaft located on the driverside side of the vehicle. It should be noted that we have seen a rotational bolt pattern difference on the 6 bolt pattern on the rear of the Jeep Torqueflite transmissions. This could cause the transfer case to clock differently when using a Wrangler 999 on a Dana 300. Advance Adapters does offer a clocking ring/ longer input to correct the rotation. We sell this under part #50-8604
The Torqueflite 999 transmission used behind the 4.0 I-6 have a provision for the crank positioning sensor. The 999 transmissions found behind the standard 258 in the CJ jeeps will not have this provision.
The 999 is relatively short at 16.5" in over length; however, the tailhousing section adds an additional 6.125". This makes the Jeep 727 an overall length of 22.625".
Torqueflite 999 Gear Ratios First gear: 2.74 Second gear: 1.54 Third gear: 1.00