Description

Dana Spicer APO1750-4, APO1000-4, AMO1750-4, AMO1000-4 2006 Service Manual

If you’ve ever had an auxiliary transmission lock up on you because somebody guessed at the air shift pressures, you know why I’m standing behind this manual. I’m Mike Callahan, 28 years turning wrenches in San Antonio, and I’ve seen more damaged countershafts from sloppy rebuilds than I care to count. This is the factory book for the Dana Spicer APO1750-4, APO1000-4, AMO1750-4, AMO1000-4 2006 Service Manual. It’s 51 pages of OEM data that will keep your rebuild inside the tolerance window – not half an inch off.

Before you pull the first bolt, you need to know that this isn’t some aftermarket reprint that skips the torque values. I’ve dealt with those – they leave you guessing on preload and end up with a whine at highway speed. This 2006 manual from Dana Spicer gives you the entire disassembly sequence, from shifter housing removal (page 5) through mainshaft and countershaft pull, and then the reassembly steps that match the production line. No missing pages, no blurry diagrams.

What’s Actually in These 51 Pages?

You get the full General Information and Description section covering lubrication intervals and power flow. Then the meat: Disassembly of the Shifter Housing Manual and Air Shift (pages 21-23), Mainshaft removal (6-8), Countershaft (10), and Drive Gear with Bearing Retainer (11). The Reassembly section mirrors that order – Mainshaft for APO/AMO/ATO on page 13, Countershaft page 14, and the trick of getting Mainshaft/Countershaft into the case (pages 18-20). Each step has the correct fastener torque and the notch alignments you have to hit blind if you skip the book.

Disassembly and Reassembly: The Right Way

The manual calls out a shop table height of 28-30 inches and warns you to steam-clean the case before opening – dirt will eat bearings inside 10,000 miles if you don’t. I’ve seen guys hammer on end yokes; the manual flat says that destroys pilot diameters and closes bearing bores. Page 2 has the caution about towing without pulling axles – that’ll starve the gear train of lube. Follow the factory callouts and you won’t be buying a new mainshaft.

3 Systems You Can’t Afford to Miss

First, the Air System Controls – page 26 gives you the charge pressure and shift valve diagnostics. Second, the Top Mounted PTO removal and reassembly (pages 35-46) with the snap ring depths and gear backlash specs. Third, the Trouble Shooting guide on page 47 – it lists common symptoms like hard shifting or noise and points you to the exact section. Without this manual you’re guessing which shifter housing seal is leaking.

Get the Torque Specs from the Source

Every fastener in this transmission was torqued on the Dana Spicer line to a specific ft-lb number. The manual doesn’t make you hunt – it’s in the step, right where you need it. For example, the bearing retainer bolts on the drive gear (page 11) have a callout that I’ve seen misprinted in third-party books. This is the factory print. You get the bulletin number SPTS001-0306, which means it’s the official March 2006 release. Pair it with the Spicer AMO1750-4 Series Auxiliary Transmission Parts Catalog for part numbers, or grab the Dana Spicer 1372-A Service Manual – Factory Specs & Rebuild Guide if you’re working on related units.

Source Validity: Why OEM Beats Aftermarket

Aftermarket manuals cut corners. They’ll give you exploded views but skip the shifter housing air shift reassembly sequence (pages 24-25) or the note about bearing replacement at 150,000 miles (page 3). This Dana Spicer manual is the same document that Tech Line 800-401-9866 uses when you call. I trust it because I’ve used it on a dozen APO1750-4 jobs and never had a comeback. For larger Dana Spicer electrical systems, check the Dana Spicer ES60-5, CM59, ES60-5A, ES60-5C, ES60-5D Service Manual – but for this auxiliary box, this is the only one you need.

FAQ

Does this manual cover the APO1000-4 model?

Yes. The cover lists APO1000-4, APO1750-4, AMO1750-4, and AMO1000-4.

What kind of troubleshooting data is included?

Page 47 has a dedicated Trouble Shooting section with symptoms like noise, hard shifting, or oil leaks, each tied to a specific component or clearance check. For example, if the unit won’t engage air shift, the manual directs you to check the air system controls on page 26 for valve pressure and line blockage. It also references the shifter housing air shift disassembly steps (pages 21-23) to inspect the piston seals. This isn’t a generic list – it’s written for the exact Spicer valve body and shift fork geometry. I’ve used it to diagnose a stuck range cylinder in under an hour because the flow chart doesn’t waste your time.

You need this manual if you’re touching a Dana Spicer AMO or APO series auxiliary transmission. I’ve torqued more head bolts than most people have had hot meals, and I won’t work on these units without the factory book. For background on how these gear trains work, see Manual Transmission and Manual Transmission on Wikipedia, but for the rebuild itself, stick with the OEM data. Access the Factory Manual and keep a copy in your tablet case – your bearings will last longer.