Muncie SS66 and SS88 split shaft PTO parts
A split shaft PTO gives you two PTO openings in the driveline when the transmission has none to spare. Here is how the SS66 and SS88 parts list is organized and how to read the tag.
SS66 / SS88 at a glance
- Type
- Split shaft PTO that installs in the driveline between the transmission and rear axle
- Openings
- Two SAE 6-bolt (SS66) or two SAE 8-bolt (SS88)
- Through torque
- 2,900 lb ft (SS66); 14,000 or 21,000 lb ft (SS88)
- Shift options
- Manual air or electric over air; cable on the SS66 only; hydraulic on the SS88
- Dry weight
- 20 lb (9.1 kg), SS66 unit without PTOs
- Main parts book
- SP17-02 SS66/SS88 Split Shaft PTO Parts List and Service Manual
What the SS66 and SS88 are
A split shaft PTO is a gear case that you put into the driveline in place of a section of driveshaft, usually where the midship bearing sat. The main driveshaft becomes its input. A shifter inside can disconnect the rear axle for stationary work, or leave it connected so the PTOs run while the truck rolls.
The SS66 has two SAE 6-bolt openings and the SS88 has two SAE 8-bolt openings. Each opening takes a side mounted PTO that you order separately, and the series, ratio and output can be different on each side. Muncie describes the SS66 as typical for chassis up to Class 5. The SS88 is the larger unit, built around a 6-pitch spur gear for big 8-bolt PTOs.
Where it fits
A split shaft does not bolt to a transmission, so it is not tied to one make. You match the through torque and the driveshaft flange size. Muncie's SS88 brochure lists the TG8, SH8, CS8 and 82 series as popular PTOs for the 8-bolt openings. For the SS66, Muncie says the two 6-bolt openings accept common series such as the TG or CS6. Muncie's installation sheet shows how to estimate through torque: multiply the maximum engine torque by the lowest transmission ratio. Its example is 500 lb ft times 5.79, or 2,895 lb ft, which is right at the SS66's 2,900 lb ft rating.
Reading an SS66 or SS88 model number
The tag reads in this order: split shaft, series, torque rating, main shaft flange, shift option, PTO mounting, special options and special features. Muncie's SS66 example is SS66-U2X3-A00XXX, and the SS88 brochure shows SS88-14X5-A00XXX.
- 66 or 88: the opening size, 6-bolt or 8-bolt.
- U2, 14 or 21: through torque, 2,900, 14,000 or 21,000 lb ft.
- X2 or X3 (SS66): X2 is the 1410 flange kit 2053740000, X3 is the 1480 and 1550 flange kit 2053750000. On the SS88, X5 covers 1550, 1610, 1710 and 1810 flanges and XC covers 1610, 1710 and 1810.
- A, C, E or H: manual air, cable (SS66 only), electric over air or hydraulic.
- 00, 0X, X0 or XX: whether each opening is open or covered. The SS66 sheet shows cover kit 2990230000, and the SS66 and SS88 books word the 00 code differently, so confirm it against the unit in hand.
Parts that wear and what to order
- Main shaft, shifter sleeve, gear and bearings: the Parts List and Description section, with the SS88 detail pages beside it.
- Shift cover parts: the manual air sections for the A option and the E option, kept separate for SS66 and SS88, with the cable kit 28TK4426 for the SS66.
- SS66 and SS88 Kits: flange kits, cover kits and seals, listed by option.
- 8-bolt kit 299B2850000 for the SS88 openings.
- Support bracket 2991970000 for the SS66, and Muncie's optional suspension bracket kit 299K2870000 for the SS88.
Questions we get about the SS66 and SS88
Can I weld a bracket to the frame to hold the unit?
Muncie's installation instructions say no. Brackets must be bolted to the frame, using existing holes where possible, and the installer supplies the mounting parts.
Does the SS66 work with a driveline parking brake?
Not as mounted. Muncie notes the SS66 is not available with a driveline brake, so a brake attached to the rear of the transmission has to be moved behind the split shaft, or another parking brake installed for stationary PTO work.
Which PTO goes in the openings?
That depends on the pump and duty. Send us the split shaft model number and the PTO you plan to mount, and see the model number guide for reading the PTO's own tag.
SS66 / SS88 parts breakdown
How the Muncie SS66 and SS88 Split Shaft 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 SS66 Series
The store also files this same book under Muncie SS88 Series.
SS66 / SS88 manuals
All SS66 / SS88 books: Muncie PTO parts manuals.
Need a complete rebuilt unit?
Our sister site rebuiltmunciepto.com covers rebuilt SS66 / SS88 units. This site is the parts and model reference side.
Get a quote on SS66 / SS88 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.