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MG MGB Technical - Gearbox ratios

Can anyone help identify when the gearbox with the higher first and second gears was used. I understand that it was only used for a couple of years in the early seventies. Is this correct and on which models was it used. Any help appreciated.

Jim
jim soutar

Here is a chart that may help.

http://www.autochart.com/MGB_Trans.html

Clifton
Clifton Gordon

From Clausager:

3-synch:
1st 3.6363:1 gearbox, 14.2142:1 overall
2nd 2.2143:1 gearbox, 8,6557:1 overall

4-synch 67-74 i.e. chrome bumper:
1st 3.440:1 gearbox, 13.446:1 overall
2nd 2.167:1 gearbox, 8.470:1 overall

4-synch 74.5 to 76 i.e. rubber bumper:
1st 3.036:1 gearbox, 11.867:1

4-synch 77 on
1st 3.333:1 gearbox, 13.03:1 overall
Paul Hunt 2010

Many thanks Clifton and Paul. Your help really appreciated. Jim
jim soutar

JIm, are you looking for something specific.

I have a 78 gearkit in excellent condition if you need it.

Colin
Colin Parkinson

Thanks Colin but I have a "79 box. I am really looking for the 74.5-76 box with the 3.036 1st gear if I can find one at sensible money. Jim
jim soutar

Hi Jim, I have a number of 4 synchro non od boxes. How can you easily tell which is which??

How many teeth on the 1st gear?

Colin
Colin Parkinson

Hi Colin. Easy way to check as its only 1st gear thats important is to engage 1st, mark output shaft and casing, then turn input shaft, counting No of turns for one full rotation of outputshaft. The box I require will need almost exactly 3 turns, next nearest is 3.33 turns which is the later 76 on box. Thanks for your interest. Jim
jim soutar

Jim, maybe you should look at this; probably the right gearbox for GBP 100!

http://www.carandclassic.co.uk/car/C85480/
Willem vd Veer

Thanks Willem I"ve emailed the advertiser. Jim
jim soutar

Hi Jim checked them all, and they are all 3.3. I do have a gear set with 1st 30T, part number DAM 0597.
I guess this is the same?

Colin
Colin Parkinson

This thread was discussed between 29/04/2010 and 06/05/2010

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