Transmission Exchange Co.

Getting a Grip on the Aisin AR5 Transmission
By Mike Weinberg

Aisin World Corp. is a large manufacturer of original-equipment automotive components including manual and automatic transmissions. AX5 and AX15 five-speed transmissions have been around for years, and the AR5 is an evolution of those designs. The AR5 is built in rear-wheel-drive and four-wheel-drive models and resembles the AX5 and AX15 designs externally, as well as the Toyota R155 five-speed transmissions

The AR5 is a five-speed transmission, with 5th being overdrive, that is found in 2005-and-up Chevrolet Colorado and GMC Canyon trucks, the 2006-and-up Pontiac Solstice and the 2007-up Saturn Skye. All gears are synchronized, and the shafts are supported by roller ball bearings, while all of the gear train is supported by needle bearings.

This design uses a four-part aluminum case made up of a removable bellhousing, main case, center support and extension housing. The rear-wheel-drive units have an oil trough mounted in the case that moves lubricant to the rear bushing. Unique to this design is an internal oil baffle mounted on the main case that keeps the oil from being thrown around the case. As these units are splash lubricated, this baffle acts to contain the oil onto the gear train for better cooling and lubrication. No shims are required to set end-play, but all retaining snap rings are selective and you should use the thickest one that will fit. These transmissions are spec’d to use a special 75-90W gear l**e, GM part # 89021806, although for better cold-weather shifting you should substitute GM synchromesh fluid.

The shift system is typical AX5/AX15 with a single main shift rail moving four shift rails mounted in the center support. There is a complex detent and interlock system in the design to prevent obtaining more than one gear at a time. Worn detents, interlocks and shift forks produce a variety of shifting problems on high-mileage units, and these should be inspected thoroughly during teardown to prevent comebacks.

The synchronizer assemblies use spring-loaded keys to engage the synchronizer ring onto the cones of the selected speed gear. The clearance level of the synchro ring to the face of the speed gear is listed at 0.031 inch. A surefire way to prevent shift issues, even on rings that meet the spec, is to clean the cones on the speed gears, use a magic marker to color the cone and then, using a known-good ring, twist the ring down on the cone and then look at the pattern it makes. You will find rings that grab only at the top or the bottom or skip around the cone, because you cannot measure a taper accurately. The five minutes it takes to test the rings will be hours of labor saved going forward.

Whenever you disassemble any synchronizer be sure to match-mark the slider to the hub so that it is replaced in the same spot during reassembly. This will always give you the proper direction that the slider was facing when it was removed, and the splines on the hub and slider will go back to the original position to avoid notchy or dragging shifts. For those of you who don’t like to take synchronizer assemblies apart if they feel good, remember that the splines between the inner hub and slider are usually loaded up with metal contaminants that fresh l**e will set loose to ruin the new bearings you just installed. The second reason to disassemble, inspect and clean the synchro assemblies is to look for cracks on the inside of the hub or sliding sleeve that could come back to bite you.

The more things change, the more they remain the same. The AR5 is a cousin to the AX5/AX15

10R140 - classic drivability complaint
by Wayne Colonna

F-350 6.7L Super Duty using the 10R140 beast of a transmission not upshifting when pulling a load only. On light throttle it will upshift, but not as high as tenth gear. Once the throttle was depressed it would downshift and no longer upshift. It displays similar symptoms to when the wrong tire size is used with vehicles that have highly sensitive curve recognition programs. In these applications (such as a BMW), when wheel speed signals indicate the vehicle is in a turn, it will prevent any shifting. If tire sizes are wrong, it can deceive the computer’s logic system in this way preventing an upshift with medium to heavy throttle. But that is not the case here. This is a 10R140 with a classic drivability complaint.

Code P1548 for an Engine Air Filter Restriction. Clearing the code, yet the problem persists. Inspect the filter , it will be loaded with dirt.

There is a restriction gauge located on the upper housing of the air filter assembly. This device measures the vacuum inside the air filter. The more the air filter is dirty or clogged, the higher the vacuum reading. When the airflow in the intake air system reaches the maximum allowable restriction limit, the air filter restriction gauge indicator moves from the yellow bar to the red bar at the base of the gauge

There have been reports that sometime in 2022, Ford eliminated the use of this gauge, so you may not find it; but if you do, it will need to be reset after the cause of the restriction is resolved. If you are an owner of a Ford Super Duty with this gauge, it is recommended that it be checked every 7,500 miles. If the truck is being used in extremely dusty conditions, this should be checked every 500 miles or two weeks—whichever comes first. The air filter will need to be changed when the restriction gauge reads near the change filter line and the gauge is yellow. Once it is in the red, the engine is suffocating, and classic drivability complaints will be present, affecting fuel economy as well.