Are 5sp manual transmissions interchangeable?
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Racer
Joined: Apr 2016
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Are 5sp manual transmissions interchangeable?
I have a 83 928 with a likely bad 5 spd manual transmission. Can I put in a used transmission from
another year?
Trying the avoid a rebuild as it could break the bank.
another year?
Trying the avoid a rebuild as it could break the bank.
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Yes, you can install anything from a 1980 G28.05 to a 1995 G28.57 , they're all dimensionally the same. '83 used a G28.08 with a 2.27:1 ring and pinion, for whatever that's worth.
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Racer
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At some point in mid-1980 the transmission got moved forwards by 30mm in order to decrease the angle of the rear axles to the centerline of the rear wheels. So the torque tube got shortened by 30 mm and the 80+ transmissions have a different input shaft (5th gear). So you'd need a different torque tube and rear 5-speed crossmember to install a '78/79 G28.03. More trouble than it's worth unless you happen to have all of those bits laying around.
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Just to pile on, your '83 transmission just celebrated its 41st birthday. Most transmissions that are out of cars and are available these days typically also need whatever your '83 needs. If you have the means to pull it, I'd do so and ship it to Greg Brown in a bigass Igloo cooler and have a known-good transmission when you get it back. No point in playing $XXXX roulette with transmissions of unknown provenance.
Thread Starter
Racer
Joined: Apr 2016
Posts: 274
Likes: 26
Just to pile on, your '83 transmission just celebrated its 41st birthday. Most transmissions that are out of cars and are available these days typically also need whatever your '83 needs. If you have the means to pull it, I'd do so and ship it to Greg Brown in a bigass Igloo cooler and have a known-good transmission when you get it back. No point in playing $XXXX roulette with transmissions of unknown provenance.
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At some point in mid-1980 the transmission got moved forwards by 30mm in order to decrease the angle of the rear axles to the centerline of the rear wheels. So the torque tube got shortened by 30 mm and the 80+ transmissions have a different input shaft (5th gear). So you'd need a different torque tube and rear 5-speed crossmember to install a '78/79 G28.03. More trouble than it's worth unless you happen to have all of those bits laying around.