Short Shift Kit
06-17-2001, 05:39 PM
#1
3rd Gear
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Short Shift Kit
I recently obtained an 84 - 911. The previous owner put on a short shift kit. I am having a tough time going into 2nd(stiff and griding). Reading the post on Mobile One might help, but does anybody recommend I switch back to the original linkage?
06-18-2001, 11:55 AM
#2
Track Day
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I had the same problem with my 85 Carrera.
When grinding occurs this "most likely" is do to the 2nd gear syncro ring being worn out of tolerance.The rings insure that the dog tooth gear is turning at a rate that it can easily mesh with the other gear ,or teeth grind. I tried all the adjusting,tweeking,SWEPCO you name it.The end rusult was to replace the syncro's and dog teeth that were worn.Note if you replace them your self be sure to measure them to the spec before complete reassembly. The first time around I did not know the spec and had recieved a new syncro out of tolerance.Pulling the motor is time consuming.Just my .02 cents! Good luck
When grinding occurs this "most likely" is do to the 2nd gear syncro ring being worn out of tolerance.The rings insure that the dog tooth gear is turning at a rate that it can easily mesh with the other gear ,or teeth grind. I tried all the adjusting,tweeking,SWEPCO you name it.The end rusult was to replace the syncro's and dog teeth that were worn.Note if you replace them your self be sure to measure them to the spec before complete reassembly. The first time around I did not know the spec and had recieved a new syncro out of tolerance.Pulling the motor is time consuming.Just my .02 cents! Good luck
06-19-2001, 12:41 PM
#3
I'm with Mully on this one. However, you might try to alleviate the problem by ensuring that your shift bushing, under shifter, is 100%; they are cheap so just replace it. While you are in there, check the tunnel rod bush; rarely wears out completely.
Next, go to the coupler and have a look at the bushing. Then readjust your clutch cable (or at least check it) and ensure that you are disengaging completely.
If all of that is well, and there is no bad trans/motor mount, I would suspect that your 2nd gear dog teeth are stretched and thus are not being affected by engagement of the synchro ring that slide in under the teeth when you go for second. DO NOT force anything or your 915 will break you wallet and your heart.
Paul F's book "The 911 Story" has a very nice writeup on how this works. Once you read and understand how the synchro rings are used to bring gears to speed, then back off, you will be amazed and love the genius of the design, despite its balkiness. You will also quickly realize how forcing a shift is asking for huge trouble. Might be time for a rebuild on these parts.
Jw
Next, go to the coupler and have a look at the bushing. Then readjust your clutch cable (or at least check it) and ensure that you are disengaging completely.
If all of that is well, and there is no bad trans/motor mount, I would suspect that your 2nd gear dog teeth are stretched and thus are not being affected by engagement of the synchro ring that slide in under the teeth when you go for second. DO NOT force anything or your 915 will break you wallet and your heart.
Paul F's book "The 911 Story" has a very nice writeup on how this works. Once you read and understand how the synchro rings are used to bring gears to speed, then back off, you will be amazed and love the genius of the design, despite its balkiness. You will also quickly realize how forcing a shift is asking for huge trouble. Might be time for a rebuild on these parts.
Jw
06-19-2001, 06:00 PM
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Mully and jdub hit the nail on the head. Just had my 85 carrera tranny put into fine shape by Jack Lewis. New bushings and shift coupler, swepco, and adj. linkage. As you may know, the 85 and86 911s came delivered with a factory short shift. Jack says they are bad news for the 915 and should be shifted with care to avoid damage. 3rd gear occasionally grinds- why? You guessed it- worn synchro but still manageable. It got much better after the work was done.
On a side note: every time I let someone drive my car they have a hard time shifting it and, in my opinion, mess up the linkage. A word to the wise- don't let other people, including DAD, drive the car. They just don't understand the meaning of clutch, pause, shift, de-clutch!
On a side note: every time I let someone drive my car they have a hard time shifting it and, in my opinion, mess up the linkage. A word to the wise- don't let other people, including DAD, drive the car. They just don't understand the meaning of clutch, pause, shift, de-clutch!
06-21-2001, 02:39 AM
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I installed a short shift kit...for about 2 hours. When i did i relaced all the bushings and was disapointed when it shfted worse thatn before so i removed the shift kit and it now shifts great. My advise... take it out and compare, it's not hard to do.