So this thread will be information, hints, tips, upgrades to the original M916, M917 and M920s that received the 7 speed upgrade.
2 types of the transmission were used a 4700SP WTEC 5 and a HD4560P WTEC 3. Both are double overdrive with .74 and .64 ratios. Both use a device similar to a cruise control module to adjust power to the transmission control module based the pull of a cable attached to the throttle. Both use an 1810 full round output yoke rather than the original 9c.
WTEC 5 TCM reprogram code : 4C0010M1007C
The WTEC 3 trucks like @Castle Bravo has were built by Northrop Grumman in the 2002 to 2004 range. Assuming as a pilot program.These units have air ride cabs, different front end/under hood bracing, and transfer case relocation. I know of 5 of these trucks.
The WTEC 5 trucks seem to be Red River trucks done in 2011 to 2013 range. A few have air ride cabs. Most were left as standard cabs. These trucks did not get the different bracing nor did they get a transfer case relocation. These trucks have ranged from Big Cam 1, 2, and 3 powerboats. These trucks seem to be more common.
They both received upgraded alternators like what is used on the FMTV trucks. Electrical systems pretty much are the same from a standard truck except for the added on transmission harness that is stand alone.
They both have a heat exchanger for the transmission mounted on the frame behind the passengers tire. They did not use a exchanger/air to air like the M915A1 uses. They retained the stock radiators.
They both have the upgraded tachnograph units.
Both have a smaller 18in steering wheel with rubber grip and a bostrom air ride seat
They both use a hydraulic control 870 series parker PTO with an RK output flange. They retained the same hydraulic pump for the winch all around with a 7/8-13 spline adapter. PTO units on these trucks are noisy non shimmed units. They do work in neutral, drive, or reverse as they are not ran off the torque converter. The pto is accessible thru the same floor access panel.
They both used the same Oshkosh 18000 single speed transfer case WTEC 3 trucks had a transfer case relocation done in which it was moved back. The original transfer case to front tandem is 33in long yoke face to face. They relocated it so that the shaft was 16 inches long. The Allison is much longer than the CAT 7155. Without moving the transfer case you have 4 inches between the transmission and it for a jackshaft. By moving it back the distance between the transmission and transfer was extended to 16 inches as well. A CAT 7155 truck as a 14in jackshaft. The front axle to transfer shaft includes a center support bearing on both variants.
The WTEC 5 trucks were opted to not relocate the transfer case but instead used an 1810 joint attached to a coupler. Which in turn bolted to the transfer input yoke. In my opinion this is a stupid design. The joint Is allowed no flex room and it isn't much fun to get out. Not to mention dinky bolts holding in the caps as retainers. It also is a 1810 half round x 4 setup. They do not make a joint like this so you have to buy two spicer 5-676x joints to make what you need. The coupler is not common and must be made by a machine shop if it breaks.
On the WTEC 5 trucks the transmission is powered and grounded with direct leads to the batteries. The Allison works off 12v only. However the ground for the PTO solenoid is located on the dash by the steering column on a dash screw as the same ground as the horn which isn't very good. I suggest a relocate. The Allison power relay box is located on the back wall beside the TCM. This box has 2 fuses in it. One that controls the power into the box from the batteries. One controls power to the controller. The one fuse Is hard to see in the box. I recommend replacing the ATC fuse with resettable ATC fuses. The unit powers up off a single yellow wire off the switch.
Pictures of a WTEC 5 truck below
2 types of the transmission were used a 4700SP WTEC 5 and a HD4560P WTEC 3. Both are double overdrive with .74 and .64 ratios. Both use a device similar to a cruise control module to adjust power to the transmission control module based the pull of a cable attached to the throttle. Both use an 1810 full round output yoke rather than the original 9c.
WTEC 5 TCM reprogram code : 4C0010M1007C
The WTEC 3 trucks like @Castle Bravo has were built by Northrop Grumman in the 2002 to 2004 range. Assuming as a pilot program.These units have air ride cabs, different front end/under hood bracing, and transfer case relocation. I know of 5 of these trucks.
The WTEC 5 trucks seem to be Red River trucks done in 2011 to 2013 range. A few have air ride cabs. Most were left as standard cabs. These trucks did not get the different bracing nor did they get a transfer case relocation. These trucks have ranged from Big Cam 1, 2, and 3 powerboats. These trucks seem to be more common.
They both received upgraded alternators like what is used on the FMTV trucks. Electrical systems pretty much are the same from a standard truck except for the added on transmission harness that is stand alone.
They both have a heat exchanger for the transmission mounted on the frame behind the passengers tire. They did not use a exchanger/air to air like the M915A1 uses. They retained the stock radiators.
They both have the upgraded tachnograph units.
Both have a smaller 18in steering wheel with rubber grip and a bostrom air ride seat
They both use a hydraulic control 870 series parker PTO with an RK output flange. They retained the same hydraulic pump for the winch all around with a 7/8-13 spline adapter. PTO units on these trucks are noisy non shimmed units. They do work in neutral, drive, or reverse as they are not ran off the torque converter. The pto is accessible thru the same floor access panel.
They both used the same Oshkosh 18000 single speed transfer case WTEC 3 trucks had a transfer case relocation done in which it was moved back. The original transfer case to front tandem is 33in long yoke face to face. They relocated it so that the shaft was 16 inches long. The Allison is much longer than the CAT 7155. Without moving the transfer case you have 4 inches between the transmission and it for a jackshaft. By moving it back the distance between the transmission and transfer was extended to 16 inches as well. A CAT 7155 truck as a 14in jackshaft. The front axle to transfer shaft includes a center support bearing on both variants.
The WTEC 5 trucks were opted to not relocate the transfer case but instead used an 1810 joint attached to a coupler. Which in turn bolted to the transfer input yoke. In my opinion this is a stupid design. The joint Is allowed no flex room and it isn't much fun to get out. Not to mention dinky bolts holding in the caps as retainers. It also is a 1810 half round x 4 setup. They do not make a joint like this so you have to buy two spicer 5-676x joints to make what you need. The coupler is not common and must be made by a machine shop if it breaks.
On the WTEC 5 trucks the transmission is powered and grounded with direct leads to the batteries. The Allison works off 12v only. However the ground for the PTO solenoid is located on the dash by the steering column on a dash screw as the same ground as the horn which isn't very good. I suggest a relocate. The Allison power relay box is located on the back wall beside the TCM. This box has 2 fuses in it. One that controls the power into the box from the batteries. One controls power to the controller. The one fuse Is hard to see in the box. I recommend replacing the ATC fuse with resettable ATC fuses. The unit powers up off a single yellow wire off the switch.
Pictures of a WTEC 5 truck below
