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| An 11,000-mile Aisin AR5 transmission from a Chevy Colorado. A staple in the drifting world, let's see what it will do in a thirdgen F-Body behind an LS engine for autocrossing. |
Project Whack-A-Mole continues. I finally figured out the fuel pump issue. The old Delphi fuel pump, struggling to deliver fuel, was replaced with a new Deatschwerks fuel pump which seemed to cure things. So I took the Camaro out for a test hit.
The car felt good driving it around some shifting through the four gears. Then I got on a more open road, mashed the throttle in second, shifted fast to third, but the car wouldn't accelerate under its own power in gear. Clutch pedal went dead, it would go through gears but they wouldn't engage. I suspected it wasn't an issue with the T10 transmission but back to the hydraulic throwout bearing, which had already failed once before.
I called Karen (she answered the phone, "Where are you?"), she picked me up, we got the Lightning and trailer, loaded the car up and took it home.
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| How the torque arm is mounted on my car with the original T10 transmission. The AR5 is a bit longer so it's going to be interesting to see how this works out. |
Towed the car to work a week or so later. With the four-speed T10 manual transmission, I told myself that if the gearbox ever came out again, it wouldn't go back in. The original T10 might be a weak link behind the 5.3 LS engine, and I had been thinking about a change. Of course the obvious answer is T56, but even used ones are really pricey. Tremec came out with a 5-speed TKX a little while ago which looks really stout, but it's $2,500+.
The drifters have found a cheap option to go behind their LSx-powered BMWs and 240SXs and whatever rear-wheel-drive cars -- an Aisin AR5 5-speed manual found in a handful of GM vehicles. They even use them to put behind Toyota JZ engines, and there is also someone who put the transmission in his LS-swapped 1986 Monte Carlo! (Really good info in that link comparing the AR5 to the usual suspects of manual transmission options.)
AR5 transmissions aren't plentiful, like any manual transmission nowadays, but when found, they are really inexpensive -- a search on Car-Part.com uncovered several used in the $500 range.
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| Part of the FABbot AR5 to LS bundle -- bellhousing, slave cylinder and Redline gear oil. Not pictured are the adapter plate, clutch and flywheel. |
It's not all that cut-and-dried to mate one of these GM transmissions to an LS engine. However, a company called FABbot already did all the homework and has all the parts needed including a super convenient bundle kit to complete the swap. Bellhousing, adapter plate, clutch, flywheel, hydraulic slave cylinder, even three quarts of Redline gear oil. They even have clutch stages ranging from 400 horsepower up to 700 so FABbot seems confident the AR5 trans will hold up to some power despite GM's rating that it's only good for 260 foot-pounds of torque. The Monte Carlo link above (see also the second part of actually installing the trans) has a good breakdown of why the rating is so low, theorizing GM only rates the transmission for its most powerful OEM configuration, which is the turbo Solstice/Redline. I should mention that I have some experience with the AR5 having autocrossed with Eric Kriemelmeyer in his turbo Solstice back in 2010.
Gearing wise, it shouldn't be too much of a difference from the ol' T10. Since my Camaro is just an autocross car, only first and second gears are a concern. The Colorado/Canyon AR5 has first/second gear ratios of 3.75/2.26. The Borg Warner T10 (supposedly original) from my car, 3.42/2.28.
I found a transmission from a 2008 Colorado from a local salvage yard with just over 11,000 miles, ordered the FABbot kit and made the plunge.
The biggest issue that doesn't make this an easy swap in an F-Body is that the AR5 doesn't have anything on the tailshaft to connect the torque arm. Thankfully my car has been basterdized enough so that's not an issue. Also the AR5 with the FABbot bell housing and adapter is about four inches longer than the T10 with the big-block Chevy bell housing, so my driveshaft is going to have to be shortened. Should also note that I did the measurements on the AR5 not with my transmission but one at work that is already in a 1970 Chevelle with an LS.
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| The T10 removed to reveal the hydraulic release bearing has blown a seal ... again. |
The Camaro has been on a lift at work for the past week or so. With the AR5 transmission at the shop, and the FABbot bundle arriving yesterday, our ace mechanic Chris finally got around to dropping the T10 and seeing what the actual issue was. Sure enough, the hydraulic bearing had blown a seal. This is an American Powertrain bearing designed for people like me who are replacing mechanical clutch linkages with hydraulics.
When I started finishing the car up earlier this year, I had installed an American Powertrain Hydramax kit to replace the old Z-bar linkage. The setup survived about 10 dyno pulls and some street driving but failed in May when I was loading the car onto the trailer to take it to an autocross. I figured maybe I didn't shim it right.
Took the car to work then, Chris found the throwout bearing in the same state as the picture to the right. He determined it needed less shims and installed another American Powertrain bearing that had already happened to be laying around at the shop (Chris has done several LS swaps with success using the same Hydramax kit). So it's a little puzzling that after two autocross runs and some street driving that the new bearing failed in the exact same way as the old one. It's not like the car has monster power (360/353 to the wheels) or I have been doing crazy launches and hard shifting.
The FABbot kit comes with a different hydraulic setup so we will see how that one fares.
Check out Part 2!
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