(reprinted from Car Craft Jan 1994)
Tremec's Ford aftermarket replacement T56 transmission assembly comes with a newT56 compatible bellhousing that replaces the existing '83-and-later T5 bellhousing while retaining the original clutch assembly, cable clutch linkage, clutch fork, release bearing, and pivot ball stud. Installation in older mechanical linkage clutch applications requires conversion to cable clutch actuation. Advance Engineering West offers a universal cable clutch linkage conversion kit for older Mustangs.
Borg-Warner developed the trans installation procedure using a '91 Mustang coupe. It requires fabricating new crossmember mounting brackets and modifying the exhaust system. The double hump crossmember and dual -cat exhaust illustrated here are typical only of '86 and later 5.0L V8 cars. Suitability of earlier single-car exhaust systems and crossmembers has not been verified, nor have the fabricated brackets been tested to see if they fit convertibles. If needed, Ford Motorsport sells a universal double-humped coup-style crossmember. The stock driveshaft must be shortened 1.5 inches and converted to use a beefy Ford "C6-style" 31 spline slip-yoke. The yoke hooks right up to the existing '90-'94 T5 driveshaft's 1350 series U-joint. Earlier Mustang T5 conversions must use a hybrid U-joint --for '87-'89, uses a 1330/1350-series; for '83 - 86, use a 1310/1350-series.
|The "Ford" T56 (Left) uses a 10 spline Ford-style input shaft that permits retention of the existing Ford clutch assembly. Its mount pad location (indicated by the straightedge) is farther back than the T5 (right). However, the shifter is in the same location as a T5, eliminating the need for floorpan modifications. The "stick" attaches using two mounting bolts, the same as a T5 shifter (or most other Hurst shifters).|
Bellhousing and Clutch Linkage
Tremec ships the trans and bellhousing as an assembly. Detach the bellhousing from the trans and bolt it in place of the original T5 bell housing. Unlike the conventional bellhousings and transmissions that we're used to, the fork, pivot stud, and release bearing attach to the front of the trans, not to the bellhousing itself. After transferring these items from the old bellhousing to the new trans, bolt the trans to the new bellhousing.
The T56 mount pad is located 5 inches farther to the rear than the T5's pad, so the stock crossmember must be correspondingly relocated. Mount the crossmember to the underbody using the stock rear mounting brackets as substitute front brackets, and adding new spacers and fabricated rear mounting brackets. This requires drilling new 3/8-inch bracket attaching holes in the floor and subframe. Remember to remove the front door scuff plates and push the floor carpet back before drilling the holes through the floor. Use GM trans mount PN17990869 to mate the trans to the crossmember. Bolt it to the trans using two metric M10x1.5x30 mounting bolts; the mount's single crossmember retention stud requires and M10x1.5 metric prevailing torque nut and a new slot in the crossmember.
|The clutch-cable and fork junction is in a different location than the stock T5 unit. To clear it, trim the production engine-to-transmission rear cover plate in the location shown.|| |
To install the fork, release bearing, and pivot stud, attach the bearing and pivot stud to the fork, slide the fork and bearing over the input shaft, and only then begin threading the pivot stud into the boss on the transmission case.
Reuse the T5 clutch release lever dust shield. Its retaining tab (arrow) must be bent outward to conform to the thicker T56 clutch arm opening lip.
|The right-and left-hand brackets are not "mirror images" of each other because the unibody contours differ on each side. Fabricate them from mild steel as shown. Welding and radius-bending are required.|
Relocate the AIR crossover tube from points (A) to (B) for trans case clearance. Cut off and discard the mounting hardware previously used to attach the exhaust pipes to the old T5 trans mount location. Heat and bend the air supply tube line frome the engine as required to mate with the relocated crossover tube.
Both the speedo cable receptacle (A) and backup light switch (B) are relocated to the passenger side. Compared to the T5 location, the speedo cable connection is also moved rearward 3.5 inches, requiring a new speedo cable. The backup light switch wire can merely be lengthened as needed. Tape off the original T5 neutral switch wire; it is no longer required. Also shown is the new center slot added to the crossmember for the GM mount's attaching stud.
This is the complete Ford T56 installation, showing the bellhousing, relocated crossmember and modified exhaust
Listed below are the critical dimensions of the T56 in comparison to T5 and traditional four-speeds. Metric dimensions are converted to inches and rounded off to the nearest 0.1 inch.