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The AR5 is an Aisin-built five-speed with fifth gear as an overdrive. GM used it as the manual option in roughly the 2004-2012 Chevy Colorado and GMC Canyon, the Hummer H3, and the Pontiac Solstice and Saturn Sky. The trucks bolt it to a transfer case on 4WD models, while the roadsters run a conventional tailhousing and driveshaft. A Sky box will not drop into a 4WD Canyon.
From the builder's side, the geartrain is not the weak link. What brings them in is the clutch release system, and the labor to get at it. Second is synchro wear from a dragging clutch nobody fixed.
Common Complaints, Ranked
| Symptom | Usual cause | Fix level |
|---|---|---|
| Pedal goes soft or to the floor, fluid disappears | Leaking concentric slave cylinder | Trans out, clutch job |
| Hard to get into gear at a stop, grinds into reverse | Clutch not releasing: slave, master, air, worn disc | Hydraulics, then clutch job |
| Grind on quick 1-2 or 2-3 shifts with a good pedal | Worn synchro rings or cones | Rebuild |
| Growl in neutral, clutch out, quiet with pedal in | Input shaft bearing | Rebuild |
| Chirp or squeal only with pedal down | Release bearing on the slave, or pilot bearing | Clutch job |
| Notchy, stiff shifts when cold | Wrong or worn-out fluid, low fill | Fluid change |
The Concentric Slave Cylinder Problem
These applications use a concentric slave cylinder, often called a CSC. It is a ring-shaped hydraulic cylinder that sits inside the bellhousing around the input shaft, with the release bearing built onto its face. There is no external slave on the side of the case. When the seal inside it lets go, fluid leaks into the bellhousing, the pedal gets soft or sticks to the floor, and the master cylinder reservoir keeps dropping with no puddle you can find.
The trouble is access. To replace a part that costs well under the price of a clutch kit, the transmission has to come out, and on 4WD trucks the transfer case is in the way too. That is why a slave failure costs nearly the same as a full clutch job. Our concentric vs external slave cylinder guide explains the design trade-off, and the slave cylinder failure guide covers the symptoms in more detail.
Diagnose it before you pull it
- Check the reservoir level over a few days. A steady drop with a dry firewall and dry master points at the slave.
- Rule out air. A system that was opened recently may just need bleeding. CSC systems can be stubborn, so follow a proper procedure like our hydraulic clutch bleeding guide before you condemn parts.
- Check the master. A slowly sinking pedal with a full reservoir points at the master.
What to replace while it is apart
Once the box is on the floor, the labor is paid. Replace the slave, disc, pressure plate and pilot bearing, and have the flywheel resurfaced or replaced. A fluid-soaked disc is scrap. Check the input shaft splines and bearing retainer, and consider the master if it is original. Our clutch kit buyer's guide covers what a complete kit should include.
Gear Grind and Synchro Wear
A clutch that drags makes every synchro do extra work. Fix the release system first and recheck. If the pedal is firm, the fluid is correct, and it still grinds on a quick shift, the rings are worn.
When you tear it down, measure ring-to-cone clearance on every gear, not just the one that grinds, and look at the cone surfaces and sleeve teeth. A glazed cone eats new rings fast. See our synchro wear guide for how to check them.
Input Bearing Noise and Shift Feel
The quick test: engine idling, in neutral, clutch pedal out. A growl that goes away when you push the pedal in is the input shaft bearing, because the input shaft stops spinning when the clutch releases. Noise that only shows up with the pedal down is the release bearing on the slave or the pilot bearing. The throwout bearing noise guide covers that side.
Stiff, notchy shifts on a cold morning are very often fluid.
Fluid
Follow GM service information for your exact vehicle and year. GM fluid guidance for these Aisin boxes has not been the same across every application. Do not default to a GL-5 hypoid gear oil unless your service info calls for it. Fill with the vehicle level until fluid reaches the bottom of the fill hole,. Browse fluids once you know the spec.
Parts and Tools for an AR5 Job
Clutch out and the box on the bench? Get the rebuild kit, hard parts and the tools to press bearings and seat seals square.
Rebuild Kits → Hard PartsWhat It Costs
| Job | Parts | Shop, installed |
|---|---|---|
| Fluid change | $30-$70 | $90-$180 |
| Bleed clutch hydraulics | $10-$25 | $80-$180 |
| Clutch master cylinder | $40-$150 | $200-$450 |
| Concentric slave only (trans out) | $70-$250 | $800-$1,500 |
| Clutch kit, slave, pilot, flywheel service | $300-$800 | $1,200-$2,200 |
| Rebuild: bearings, synchros, seals | $300-$650 | $1,600-$2,600 |
| Rebuild with gears or sleeves | $650-$1,300+ | $2,200-$3,500+ |
| Used AR5, unknown history | $500-$1,400 | $1,300-$2,600 |
Ranges are ballpark; 4WD trucks run toward the high end of labor. If the slave goes and the clutch is more than halfway worn, do the whole clutch on the same pull. Shop rebuild kits and hard parts, and our sister store CoreTransmissionParts.com carries transmission parts as well. If the truck also has 4WD engagement issues, read the Colorado and Canyon transfer case shift motor guide before it goes back together.
DIY, shop or used?
- DIY clutch and slave is reasonable with a transmission jack, a lift or tall stands, and a helper.
- DIY rebuild needs a press, pullers and a manual. End play has to be set correctly.
- Shop rebuild if it is your work truck or daily driver.
- Used is a gamble on age. Match the case tag and drive type, and only buy if the price leaves room for a rebuild later.
Tools that make it easier
A bearing separator and puller set gets pressed bearings off without damaging gears, and a bearing race and seal driver set seats new bearings and the front seal square. A pilot bearing puller is worth having for the clutch side. For stubborn bearings, use a hydraulic gear puller or press plate kit. More in tools. Compare the NV3500 if you build other truck boxes.
FAQ
Which GM vehicles used the Aisin AR5?
The AR5 shows up as the 5-speed manual option in the 2004-2012 era Chevy Colorado and GMC Canyon, the Hummer H3, and the Pontiac Solstice and Saturn Sky. GM paperwork and parts listings label it AR5 or MA5 depending on the source, and not every trim or engine got it. Confirm with the RPO code on the glovebox or door sticker and the tag on the case.
Why does the clutch slave cylinder on these trucks need the transmission pulled?
The AR5 applications use a concentric slave cylinder that sits inside the bellhousing around the input shaft and doubles as the release bearing. There is no external slave to unbolt, so the transmission has to come out to replace it. That is why a slave failure costs about the same labor as a full clutch job.
Why does my AR5 grind going into gear?
Check clutch release first. A weak or leaking concentric slave, air in the hydraulics, or the wrong fluid will make good synchros grind. If the pedal is firm, the fluid is correct and it still crunches on a quick shift, the synchro rings or the cones they ride on are worn and the box needs to come apart.
What fluid goes in an Aisin AR5?
Use the manual transmission fluid called for in GM service information for your exact vehicle and year. GM has issued different fluid guidance across these applications, so do not assume a generic GL-5 hypoid gear oil is correct. Fill to the bottom of the fill plug hole with the vehicle level.
Is it worth rebuilding an AR5 or should I buy a used one?
If the box is quiet and only the clutch hydraulics failed, do the clutch and slave and leave the transmission alone. If it has bearing noise or synchro grind, a rebuild with bearings, rings and seals is usually the better value because used units carry the same age and unknown history. A used box makes sense only when the price leaves room for a rebuild anyway.