Transmission, Manual

Loss of 4th Gear

I was driving my 84's 5 speed last night crusing along in fourth gear and boom the car goes out of gear.... I place the stick in 4th and no 4th? It sounds like the linkage to me but all my other gears are fine. Does anyone have any other Ideas what it could be...God I hope its not the tranny...

Thanks,
BB
84 Black 5 speed.



All five gears on a 928 transmission are engaged with a combination of dog teeth (pressed onto the gearset itself) and operating sleeves (slid onto the dog teeth with the shift forks). One of the costs of missed/clashed shifts is dulling or breaking the dog teeth. Under the worst of conditions the dog teeth are broken completely and that gear won't engage at all. When the dog teeth and operating sleeves get worn, then can disengage while under tremendous force (as in acceleration) and do themselves some severe damage, and when this begins to happen it's time for a rebuild.

Externally, the gears are selected in pairs (1/R, 2/3, 4/5). You select the pair by how far right or left you position the shifter, and the specific gear by moving it forward or back. If you can select reverse and 2nd gear, then the linkage can move far enough forward (actually backwards at the transaxle), and if you can select 5th, you can move the linkage far enough right. Being unable to select 4th tells me that the dog teeth in 4th are toast.

Sadly, I think your transaxle is going to have to be rebuilt.

Dave Cooley