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C3 Transmission Swap - Grabbin' New Gears

We Install Keisler Engineering's New T45-RS Into A '69 C3

Alan L. Colvin Nov 1, 2009
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Back a couple of months ago, I got a phone call from Shafi Keisler, owner of Keisler Engineering, about a new 5-speed transmission that had just been released for the C3 Corvette at just $2,195-a thousand dollars less than their current Tremec TKO offering! Well, to say the least, he had my undivided attention. That transmission turned out to be the Keisler T45-RS, which is based on the Borg-Warner T-45 that was used from 1996-2001 in high performance passenger cars including the Cobra and 4.6L Mustangs.

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Keisler buys the T-45 from reliable used transmission sources and then remanufactures each transmission in-house with a number of upgrades and custom features that greatly improve the reliability/durability of the gearbox. The T45-RS is a Double Cone transmission with all forward gears and reverse fully synchronized and shares many internal components with the famous T-56 6-speed.

The T45-RS rebuild includes all new upgraded carbon fiber synchronizers, bearings, seals and gears (as required), a new high strength alloy front casting that allows the T45-RS to bolt up to the standard GM bellhousing bolt pattern, and a new super duty input shaft (either standard 10-spline/1-1/16" or optional 9310 chromoly 26-spline/1-1/8"). Keisler also offers a choice of electronic or mechanical speedometer output for the T45-RS and uses a high strength 31-spline output shaft.

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The T45-RS comes in two builds, 350HP and 425HP. The primary difference between the two transmissions in that the 425HP version uses the larger 26-spline input shaft while the 350HP version uses the 10-spline input. Both transmissions use the same gear ratio as follows: 3.37 1st, 1.99 2nd, 1.33 3rd, 1.00 4th, .67 5th; 3.22 Reverse which equates to a 33% drop in engine RPM in 5th gear.

The T45-RS uses a custom billet aluminum short throw shifter that has been custom designed to work in all 1968-82 Corvettes. An optional C3 replica shift handle is also available that not only gives you an original look but also places the shifter at the correct height. We used this shifter in this build and as you will see later, it looks, works, and feels great!

Keisler provides the T45-RS in kit form. Their proprietary designs include a crossmember mount bracket, rubber transmission isolator (poly upgrade available), back-up wiring harness, forged quick release slip yoke, driveshaft, 5-speed shift pattern plate, template and tunnel cover, installation hardware kit, and an installation manual. Each T45-RS is 100% spin tested and leak checked prior to shipment and comes with a 6-month warranty (extended warranty available at extra cost).

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One of Keisler's key ingredients to their transmission kits is their driveshaft program. Keisler builds all their driveshafts in-house on their Hines driveshaft cell from lightweight high strength steel that is automatically welded and computer balanced with premium solid sealed U-joints. Each driveshaft is then painted satin black, certified and serialized.

Well we have talked enough about the specifics of the T45-RS transmission for now. The result of the initial phone call from Shafi was an invitation to fly up to the Keisler plant for a T45-RS install into a '69 C3 and a test drive. It didn't take too much arm twisting for me to be on a plane pronto to go thrash a hot 5-speed C3 through the hills and dales around Knoxville, Tennessee, so that's exactly what happened. Follow along with us now as we install the tranny in the car and then we will take the car out for a test drive in next month's issue. Let's get to it!



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