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MG MGA - 1600 gearbox rebuild basics

I have a 1962 MGA MkII with 68k miles on it. My gearbox works pretty well and is not generally noisy, but it often crunches going down into second and the
stick vibrates noisily at high revs in third. I am going to change the second gear synchro ring, but I would like to know what other parts it would be wise to check or change while I am in there. Any help would be appreciated,
T Horncastle

Hi, in addition to changing second gear synchro ring, you should likely change the large input shaft bearing, the layshaft and layshaft needle bearings, the layshaft end washers (if layshaft end clearance is excessive), the clutch fork pivot bushing and bolt, and the carbon clutch release bearing. Might not be a bad idea to replace the 3 shift rod detent springs as a precaution, since they lose tension over time, and cause the tranny to jump out of gear. I would also replace the front and rear oil seals, and all gaskets. I would also replace the clutch pressure plate and clutch disc, unless they have seen few miles. Hope this helps! GLenn
Glenn

Glenn, really appreciate your comments. Disassembled the box today(mostly) and the input shaft bearing does feel loose. Any ideas on how to get the bearing out, its doesn't want to move?
Thanks. Terry.
T Horncastle

Hi Terry. Remove the nut holding the bearing in place. It is left hand thread. You have to bend up the locktab before removing the nut. The bearing needs to be pressed off the shaft. Cheers! Glenn
Glenn

The transmission in my MG has not been worked on in 30 years but it still seems to run fine and shift smooth. The one problem I have is that is pops out of second gear when you let off of the gas pedel. Are the detent springs mentioned above the culprut of the problem? Also how much play should there be in the input shaft bearing. Mine has quite a bit and I was wondering if I should replace it?

Thanks,
Jake
Jake

Hi Jake. Yes, the detent springs are the likely culprit for your tranny jumping out of gear. There is a minor modification that can be made to the tranny to improve repair of this defect. if memory serves, this mod is described on Barney Gaylord's excellent website in the transmission section, although I could be wrong about this. As for play in the input shaft bearing, a whisper of slop is quite normal. If the bearing is at all noisy with the engine running and the transmission in neutral, you might want to replace it. In my experience these bearings will continue to work quite well, even with considerable slop present, however, the noise level may be get worse, and be a bit much to endure. Hope this helps. Glennsmga@operamail.com
Glenn

Thanks for your quick response. I have one more question. Often when driving and when comming to a complete stop I can not get the car into 1st gear and end up starting out of second. Is there anything I can do to fix this. As a work around I end up going through each gear and I don't have any problems. What I mean by this is if I am in third gear and come to a stop I have to shift into second then into first. If I try to go directly into first it usually won't go. I then go back to second gear and return to first hear with no problems.

Thanks,
Jake
jake

Hi Jake. First gear is non synchromesh, meaning that it is often difficult to engage reverse gear. This is simply a result of primitive engineering. You can try slowing the car to a crawl, and then engaging first gear. Sometimes it works, sometimes not. You can also learn to double clutch. This can be fairly effective, but over time can add to wear on the carbon release bearing. Most owners seem to just accept the reluctant first gear as normal, and rock through other gears before engaging first gear. i know of at least one person who installed an MGB all synchromesh tranny, for the very reason you are complaining about! Cheers! GLenn
Glenn

Hi Jake. Meant to say difficult to engage first gear, not reverse, although that is sometimes trick also! lol
Glenn
Glenn

This thread was discussed between 02/04/2005 and 09/04/2005

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