Fourth Gear grinding
#1
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Pulled the AO4 trans apart to find the fourth gear synchro worn out.
Spec for the synchro to gear is 0.5mm. As you can see in the photo clearance is zero. I was surprised the 4th gear shows little issues, and is serviceable. My old GM Muncies would have been toast.
Spec for the synchro to gear is 0.5mm. As you can see in the photo clearance is zero. I was surprised the 4th gear shows little issues, and is serviceable. My old GM Muncies would have been toast.
#5
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Very worn friction surface and the gear as shown. With a new synchro, I measure 1mm, with in spec for reassembly. I do not beat my transmissions, so should be good to go.
I have some wear on the first gear main shaft. May substitute 924s main shaft and first gear set.
I have some wear on the first gear main shaft. May substitute 924s main shaft and first gear set.
Last edited by Alan 91 C2; 06-18-2013 at 02:31 PM. Reason: added data
#7
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Most 924S/944 NA transmission parts are not interchangeable w/ a Turbo trans. Fairly certain the input shaft will need to be replaced w/ a 944S/S2/Turbo/TurboS part. Double check the bearing sizes.