QuestionHi.
I am the lucky owner of a 1965 MGB, which have provide me much joy since
1991. However...when I started it up this spring, a noise came from the
gearbox and it just got louder and more awful over the summer. After a little
research (including studing this site) I decided a few weeks ago that the right
thing to do was to pull the engine in order to dismantle the gearbox and find
and fix the problem. So far so good. I am living in Denmark and English is my
second language and I have come to a point where I don't really get my
Haynes manuel! I have the whole gearbox out (and it is sitting on my kitchen
table) My first problem is to dismantle the gearbox itself. I've looked the
internet for videos or instructions but with no luck. I could use help finding a
manuel or other instructions. My second problem, I suspect, is to find the
problem causing the noise -When I look inside the gearbox it looks extremely
clean and all I can see that would be out of the ordinary is two teeth missing.
Finally, anything to bring my attention to things I should be aware off when I
assembly the thing again, would be greatly appreciated.
Best regards
Miller
AnswerHi Miller,
Your English is better than mine. And you qualify as a true MG enthusiast having a gearbox apart on your kitchen table. Cool!
Yes, two teeth missing is very large noise and was in danger of destroying the whole gearbox. (under load the teeth can start to climb up on each other when teeth are missing and the gearbox will explode (split the case)
Remove the rear tower and rear housing and the bell housing and extract the lower laygear shaft. This allows the laygear to drop down in the case. Then use a thin rod as a punch try to drive the rear bearing out a little exposing the large bearing clip. Then use large flat pry bars to work the rear bearing out of the case. Do the same with the input shaft (first motion shaft).
Once you have the front shaft out and the rear bearing out of the case you can remove the whole main shaft with all it's gears on it out the side cover.
Just follow the book on checking end play in the gears on the main shaft and replace all the syncro rings. Inspect the laygear shaft for pits and replace the shaft and all of the needle bearings if you find ANY pits. check the ware on the two thrust bearings at each end of the laygear and check for excess end play in the shift forks in their grooves in the sliding hub assemblies. (Don't unload either of the sliding hub assemblies)
Check the large bearing on the input shaft and the large bearing on the main shaft and the needle bearings in the back of the input shaft.
Look at the condition of the reverse idler gear.
If you run into trouble let me know.
Howard
