Muncie PTO installation and operation guide

Before you start

• Stop the engine and put the keys in your pocket. Nobody works under the truck with the engine running.
• Chock the wheels and block any raised body or boom.
• Read the whole manual for your series first. Muncie ships each PTO with warning labels for the frame rails, the dash and the sun visor, and they belong on the truck when you are done.

Mounting the PTO

1. Listen first. Drive the truck in and run the transmission in neutral so you know what it sounds like before the PTO goes on. On a manual transmission, make sure the gears stop within a few seconds of pushing the clutch; if they do not, adjust the clutch before installing the PTO.
2. Open the aperture. Drain the fluid from a manual transmission. On an Allison automatic Muncie says not to drain it, but expect a little oil when the cover comes off. Remove the cover plate, keep dirt out of the opening, and if the cover has a magnet, move it to the other opening.
3. Clean and inspect. Clean the mounting pad and clear old thread sealant out of the bolt holes. Look at the transmission's PTO drive gear; a nick on it will be heard once the PTO is running. Rock the gears by hand to get a feel for their backlash.
4. Fit the studs. Install studs in the holes that the PTO's cap screws cannot reach, until the stud barrel is level with the pad. Muncie gives about 30 to 35 lb ft on a 6-bolt pad and 45 to 50 lb ft on an 8-bolt pad for this.
5. Shim it. Place the mounting gasket or shim over the studs with a thin film of transmission oil, never a permanent sealant, because you may need to change the stack. At least one gasket is always used, and no more than four are stacked.
6. Set the backlash. Hang the PTO on the studs, snug the top and bottom nuts, and check the play of the PTO input gear through the shift cover or inspection opening. The target is 0.006 to 0.012 inch. The thin 0.010 inch gasket in the kit changes backlash by about 0.006 inch. A dial indicator on a PTO gear tooth gives the most accurate reading; check several points around the drive gear and set to the tightest.
7. Torque. Muncie lists 40 to 45 lb ft for the mounting nuts or cap screws on a 6-bolt pad and 50 to 55 lb ft on an 8-bolt pad, unless your stud kit says otherwise. Recheck the backlash after torquing.
8. Close it up. Refit the shift cover or inspection cover with its gasket, making sure the shift fork sits in the gear or collar groove. The manual gives 14 to 18 lb ft for these cap screws, and on the TG Series the cover is tightened in an X pattern from the centre out.
9. Test. Start the engine briefly with the transmission and PTO in neutral and listen. A whine means too tight, add a gasket; a clatter means too loose, remove one. Then repeat with the PTO engaged. Keep these runs short until the transmission is refilled.
10. Refill and leak check. Refill with the transmission maker's approved fluid, run 5 to 10 minutes, and check every fastener. Muncie also asks for a second leak check after the unit has sat for an hour.

Some installations differ: certain Eaton transmissions use a gasket eliminator instead of shims, Allison 1000 and 2000 installations use a spacer with a wider backlash range, and PTOs with the "6F" mounting option use two dowel pins. The series manual covers these.

Adapters and filler blocks

An adapter gear assembly is usually fitted to reverse the PTO's output rotation or to move it clear of an obstruction; a standard adapter moves the PTO out about three inches, and Muncie notes adapters can lower the usable rating. The adapter is shimmed to the PTO on the bench first, then to the transmission, each joint to the same 0.006 to 0.012 inch backlash. Adapter plates convert an 8-bolt aperture to a 6-bolt PTO, and filler blocks space a PTO out where a transmission needs it. See Muncie PTO adapters.

Direct mount pumps and drivelines

Support the pump. Muncie requires a rigid support bracket, tied to the transmission and the rear of the pump, when a direct mount pump weighs more than 40 lb with fittings, oil and hose, is longer than 12 inches, or is a tandem or multi-section pump. An unsupported pump is one of the classic causes of a cracked PTO housing.

Grease the splines. Put anti-seize or high temperature, high pressure grease on the PTO and pump shaft splines before the pump goes on. PTOs with a greaseable output (the "G" option) have a fitting to add grease after the pump is mounted.

Driveline angles. The PTO shaft should be parallel to the pump shaft within 1.5 degrees, the yoke ears in phase, and the working angle limited by speed:

Muncie asks to be consulted for driveline speeds over 2,500 RPM.

Shifting the PTO the right way

Every Muncie stationary procedure starts the same way: parking brake set, wheels chocked, transmission in neutral or park, and the operator in the seat whenever the engine runs with the transmission in gear.

• Manual transmission: push in the clutch, wait for the gears to stop, shift the PTO in or out, then let the clutch out.
• Automatic transmission with a manual or air shift PTO (such as the SG, TG, SH, RL, RG, 82 and 83 Series): with the engine at idle and your foot on the brake, put the transmission in a drive range to stop the gears, shift the PTO, then go back to neutral or park. A grind means stop and start over.
• Clutch shift PTOs: engage with the switch at idle, then bring the engine up to working speed. Do not engage under heavy load or above about 1,200 RPM; an overspeed control can enforce that.

In cold weather, let the transmission warm up before engaging, and let the pump run unloaded for a few minutes before using the equipment. A clutch shift PTO's output can creep in the cold even when it is switched off.

Maintenance

• Service the PTO with the transmission, following the vehicle maker's severe service fluid interval, and keep the oil level right.
• Recheck the mounting fasteners, leaks and shift linkage within the first week of use.
• Look under the truck for leaks at least weekly.
• On severe duty, inspect the whole PTO system about every 100 hours, including the pump shaft grease.
• Check gear wear by pulling the shift or inspection cover; pitting, galling or cracked teeth mean a rebuild.

The source

This page summarises Muncie Power Products' PTO installation and owner's manual for 6-bolt and 8-bolt units (IN84-03), which is in the general section of our manuals page along with the series books. When the series manual and this page differ, follow the manual.