Muncie CS6, CS8, CB6 and CB8 PTO parts
The CS6 and CS8 are Muncie's clutch shift PTOs for automatic and manual transmissions, and the CB versions add a shaft brake. Here is how to read the tag and the parts list.
CS6 / CS8 at a glance
- Type
- Clutch shift PTO with internal wet clutch and standard drag brake
- Mounting
- SAE 6-bolt (CS6) or SAE 8-bolt (CS8)
- Speed ratios
- 03 (0.33:1) to 12 (1.15:1), plus 14 (1.44:1) on 8-bolt units
- Top rating
- 300 lb ft intermittent at ratios 03 to 07
- Approximate weight
- 47 to 49 lb (21.3 to 22.2 kg)
- Main parts book
- SP96-05 CS6, CS8, CB6 and CB8 Series Parts List and Service Manual
What the CS6 and CS8 are
The CS6 and CS8 engage with an internal wet clutch pack, so the PTO can be switched on and off without stopping the transmission's drive gear. The CS6 mounts to an SAE 6-bolt opening and the CS8 to an SAE 8-bolt opening. Both have a ductile iron housing and a standard drag brake to stop the output shaft turning when the PTO is off.
The CB is the optional shaft brake version. Instead of a drag brake it has a second multi-disc pack that is released when the clutch engages and applies when the clutch lets go. It needs no adjustment, and it is built only with the 1 1/4 inch keyed shaft or SAE B 7/8 inch spline output, in arrangements 1 or 3.
Where it fits
Muncie designed these for automatics such as the Allison 1000 and 2000 Series, Aisin, the older Allison AT, MT and HT Series, JATCO and the Fuller CEEMAT, and for many Mack and Spicer manual transmissions. The current input gear list covers Aisin (I84), Allison (A67), Eaton and PACCAR (E80), Mack (M65), Spicer (S68) and universal (U60, U68), and the parts list adds more. Muncie also publishes instructions for the 2013 to 2024 Ram with the AS66RC or AS69RC (CS6B), Hino with the Allison 2500, Aisin MY600 and A465, and Eaton Fuller UltraShift.
Reading a CS6 or CS8 model number
A tag reads: series, mounting, input gear, speed ratio, shift type, assembly arrangement, output, special feature. Muncie's example is CS 6B-A67 05 S 3 K P: a clutch shift PTO on a 6-bolt metric stud mount, Allison A67 input gear, ratio 05, 12 volt electric over hydraulic shift with integral solenoid, arrangement 3, an SAE B 7/8 inch spline output and pressure lube. A CB unit shows CB in the first position.
- Mounting: 6B, 6D and 6S for 6-bolt; 8B, 8D, 8S and 8F (Eaton Endurant E80) for 8-bolt.
- Shift: A manual air, E electric over air, H and J electric over hydraulic for automatics (12 and 24 volt), and S, U and other codes for integral solenoid versions.
- Arrangement: 1 to 4, covering right or left side with the shaft low and gear to the rear.
See the model number guide.
Parts that wear and what to order
- Rebuild kits by ratio and output. The parts list has separate CS6 kits for ratios 03 and 04, ratios 05 to 14 (before 2012), ratios 05 and 14 (2012 and later) and outputs I, Z and D, plus CS8 and CB6/8 kits.
- Clutch pack parts: friction discs, spacer discs, piston and spring, which Muncie lists in its CS6/CS8 output shaft sub-assemblies sheet.
- Bell gear and input gear from Tables A and B, with the bearing shims and cone spacers from Tables C.1 and C.2.
- Gasket kits (CS6GSK and CS8GSK) and the Table E gaskets.
- Shift kits: manual air, electric over air, and the electric over hydraulic systems, with or without the System Protection feature.
Questions we get about the CS6 and CS8
The shaft keeps turning with the PTO off. What do I do?
Check the plumbing for restrictions first, then adjust the drag brake: use a 3/16 inch Allen wrench to turn each end cover set screw 1/4 turn clockwise, then restart and watch the shaft.
How hard should I load it, and at what speed?
Muncie says clutch shift PTOs should not be engaged under heavy load or at engine speeds over 1,200 rpm. The optional SPD-1000A blocks engagement above a safe speed.
Why does my Allison 1000 or 2000 PTO make noise when off?
Muncie says noise that eases or stops once the PTO is engaged is common on those installations. Installing with both gaskets supplied can help on some models. See PTO troubleshooting.
CS6 / CS8 parts breakdown
How the Muncie CS6 and CS8 Clutch Shift PTO parts list is organised on our store. Each section opens the exploded view with every part number, the quantity used and an order button.
Muncie CS6 Series
The store also files this same book under Muncie CS8 Series, Muncie CB6 Series, Muncie CB8 Series.
CS6 / CS8 torque and horsepower by speed ratio
| Speed ratio code | Intermittent HP at 1,000 RPM (kW) | Intermittent torque lb ft (Nm) | Continuous torque lb ft (Nm) |
|---|---|---|---|
| 03 | 57 (43) | 300 (407) | 210 (285) |
| 04 | 57 (43) | 300 (407) | 210 (285) |
| 05 | 57 (43) | 300 (407) | 210 (285) |
| 06 | 57 (43) | 300 (407) | 210 (285) |
| 07 | 57 (43) | 300 (407) | 210 (285) |
| 09 | 52 (39) | 275 (373) | 193 (261) |
| 12 | 52 (39) | 275 (373) | 193 (261) |
Ratings as published by the manufacturer for the Muncie CS6 and CS8 Clutch Shift PTO. Check the current Muncie application data for your transmission before you size a pump.
CS6 / CS8 manuals
All CS6 / CS8 books: Muncie PTO parts manuals.
Need a complete rebuilt unit?
Our sister site rebuiltmunciepto.com covers rebuilt CS6 / CS8 units. This site is the parts and model reference side.
Get a quote on CS6 / CS8 parts
Send the model number off the PTO tag, a part or item number, or simply what the PTO is bolted to. A parts specialist answers during business hours.