Muncie A20, A30, A40 and A50 PTO parts
The A-series is Muncie's current line of 10-bolt PTOs for the Allison 3000 and 4000, two clutch shift and two constant drive. This page sorts out which is which and how to read each tag.
A20 / A30 / A40 / A50 at a glance
- A20 and A30
- Medium duty: A20 clutch shift, A30 constant drive; up to 415 lb ft
- A40 and A50
- Heavy duty: A40 clutch shift, A50 constant drive; up to 646 lb ft on the A40
- Mounting
- 10-bolt, Allison 3000 and 4000 series (transmission code A10)
- A20 and A30 ratios
- Nine codes, 05 (.54:1) to 15 (1.48:1)
- A40 and A50 ratios
- Nine codes, 05 (.63:1) to 13 (1.24:1)
- Approximate weight
- A20 47.2 lb, A40 55 lb, A50 46 lb
- Main parts books
- SP21-01 A20 and SP21-02 A30
What the A-series is
All four are 10-bolt PTOs designed for Allison 3000 and 4000 series transmissions. The model tells you the job: the A20 is a medium duty clutch shift, the A30 a medium duty constant drive, the A40 a heavy duty clutch shift and the A50 a heavy duty constant drive. A clutch shift unit is engaged from the cab by a solenoid; a constant drive unit has no clutch and turns whenever the transmission's PTO gear turns, which suits pumps that replace a front engine drive.
Muncie lists the A20 and A30 for dump, refuse, utility, tow and recovery and snow and ice work, the A40 for fire and rescue, refuse, feed mixers and vacuum trucks, and the A50 for refuse, snow and ice, cranes and concrete mixers. The A20 and A30 have a 30-position pump flange; the A40 and A50 have a low profile housing.
Where it fits
Every model number carries transmission code A10, which Muncie defines as the Allison 3000 and 4000 series. Installation manual IN21-01 covers all four and calls for mounting capscrews at 45 ft lb. For Hino chassis with an Allison 3000, the A20 has H2 and S2 shift codes for 2021 and newer. All four work with the EX Drive shaft extension; see PTO shaft extensions and EX Drive.
The A20 and A30 share one rating per ratio: 400 lb ft at 05 and 06, 415 at 07, falling to 205 at 15. The A40 and A50 brochure lists continuous ratings by Allison series, such as 571 lb ft at ratio 05 on a 3000 series. Ratio codes differ between the pairs: 05 is .54:1 on an A20 but .63:1 on an A40.
Reading an A-series model number
The A20 and A30 tag reads: series, transmission, ratio, shift option, arrangement, output, special feature, flange position. Muncie's example is A20-A10 07-HX 3 BB PX XX: an A20 for Allison, ratio 07 (.73:1), 12 volt integral solenoid, arrangement 3 (left side shaft low), SAE B 2 and 4 bolt output, standard hose kit, flange shipped loose.
- Shift option: HX 12 volt, JX 24 volt, HR and JR remote solenoid, SX and SR Muncie Start. MX is constant drive, the only option on an A30.
- Arrangement: 1 right side shaft low, 3 left side shaft low, 5 straight out from the opening.
- Output: 1X round keyed shaft, BB and BS SAE B, CC SAE C, PB and PS SAE BB, ZB SAE C shaft with SAE B flange, II DIN 5462, X2 and X4 companion flanges, CB extension.
- Flange code: a letter and number such as B1 or P2, XX for loose, blank for default.
The A40 is A40-A10 05-HX-3-CC-PX and the A50 is A50-A10 05-MX-3-CC-PX, in the same order without a flange code. See the model number guide for other series.
Parts that wear and what to order
- Rebuild kits by ratio: A20-RBK-05A for ratios 05 and 06, A20-RBK-07A for 07 to 15; A30-RBK-05 and A30-RBK-07 split the same way. Gasket kits are A20-GSK and A30-GSK.
- Input gear (Detail D), output gear and output shaft (Detail A), each by ratio or output code.
- A20 solenoid valves: 35T40860 (12 volt), 35T40864 (24 volt) and 35T62496 (12 volt Muncie Start).
- Lube fitting: units built August 2024 and earlier use a -4 fitting, 43M68014, and a blue painted rear cover; later units use the -5 fitting 43T64636.
- Shims: shaft end play is set between 0.001 and 0.005 inch. Stud kit 20TK6566.
Our parts lists cover the A20 and A30. For an A40 or A50, send us the tag.
Questions we get about the A-series
How do I tell an A20 from an A30?
Read the shift option. The A30 is always MX, constant drive, and Muncie says Muncie Start is not available on it.
What does the flange position code mean?
The output flange turns to 30 positions. Muncie stamps a letter and number on the flange and cover, and adding that code to the model number ships the flange pre-set.
Which rebuild kit do I order?
Match the series and the ratio, 05 or 06 versus 07 and up.
A20 / A30 / A40 / A50 parts breakdown
How the Muncie A20, A30, A40 and A50 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 A20 Series
Muncie A30 Series
A20 / A30 / A40 / A50 manuals
All A20 / A30 / A40 / A50 books: Muncie PTO parts manuals.
Get a quote on A20 / A30 / A40 / A50 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.