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Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one

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Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #1
MG Maniac Hughes Walsh Monmouth, ME, USA Sign in to contact	Topic Creator (OP) Mar 31, 2015 01:42 PM Joined 9 years ago 7 Posts

Hi,

I am looking for a 4 Speed overdrive Transmission for my 1979 MGB which would mate to a 215 V8. Looking for a shop who sells rebuilds for core trade-ins.

Thanks!

Hughes

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #2
tannyo Tanny O'Haley North Hollywood, CA, USA Sign in to contact 1967 MG MGB GT	Mar 31, 2015 01:46 PM Joined 14 years ago 818 Posts

http://www.quantumechanics.com/qm-htm/mgb1.htm

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #3
ErnieY Ernie Y Albatera, Alicante, Spain Sign in to contact 1976 MG MGB GT	Mar 31, 2015 02:46 PM Top Contributor Joined 12 years ago 19,528 Posts

I'm not sure what a 215 V8 is but assuming it puts out more power than the 137hp the standard MGB V8 did an MGB 4sp OD box is unlikely to be strong enough.

They tried to get away with it in the beginning but quickly discovered that the first motion shaft was not up to the job and would frequently break teeth so had to redesign it it, I'm not sure if those parts are still available.

The V8 OD (red label) also had special springs and ran at a higher pressure.

You might be better off with a 5 speed box.

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #4
MG Maniac Hughes Walsh Monmouth, ME, USA Sign in to contact	Topic Creator (OP) Mar 31, 2015 02:57 PM Joined 9 years ago 7 Posts

Thanks for the information. Can you recommend a 5 Speed that would mate up to the 215 (Olds) V8??

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #5
ErnieY Ernie Y Albatera, Alicante, Spain Sign in to contact 1976 MG MGB GT	Mar 31, 2015 03:03 PM Top Contributor Joined 12 years ago 19,528 Posts

I'll have to leave that to others I'm afraid, I know nothing of what's available on your side of the pond.

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #6
2putt Darrell Levine Winnipeg, Winnipeg, Manitoba, Canada Sign in to contact 1975 MG MGB "Red Rocket" 1978 MG MGB	Mar 31, 2015 03:03 PM Joined 17 years ago 820 Posts

I've had a MG4sp/ OD hooked up to two different 231 Buicks,......threw a rod in the first engine,.....replaced with a later more powerful version 4bbl carb and intake,.....I've broken 3 Clutch Discs,.....not worn out,... but broken discs...40k miles.....yet the tranny has held up,.....

Edited 1 time(s). Last edit at 2015-03-31 05:45 PM by 2putt.

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #7
ohlord Rob C A tiny Island off the coast of Washington State, N.W., USA Sign in to contact 1957 Land Rover Series I "EYEYIYI" 1957 Land Rover Series I "OVRLND" 1971 MG MGB 1971 MG MGB "Bedouin 2" & more	Mar 31, 2015 06:06 PM Top Contributor Joined 12 years ago 28,878 Posts

Install a T-5 stronger and you can run a .63 5th gear.
Visit the engine swaps forum for suppliers of the parts needed besides the T-5

LNDRVR4X4.COM
Home of Project "INCARN8'

1957 Series 1 Land Rover electric VEHICLE CONVERSION

FIXITUPCHAP.COM
FIXITUPCHAP INCORPORATED

RD3 Radar/ Electronic Warfare Technician
VIETNAM 1969-1972

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #8
Peter-Sherman Peter Sherman Melbourne, Australia Sign in to contact 1975 MG MGB V8 Conversion	Mar 31, 2015 10:23 PM Joined 16 years ago 6,513 Posts

MGB Overdrive box won't manage.
A T5 will. There are various ratios. You may even find one that bolts to your engine. If you don't then http://www.aluminumv8.com/ can help.
Which T5 to choose? There are a few versions.
It depends on your diff ratio of course but keep in mind that;
-you don't want to have your foot on the clutch all the time when manoeuvring through heavy traffic or car parks etc, That means your first gear should be geared about the same as it is now and second gearing should be low enough for acceleration from stationary.
-Your motor has a most efficient RPM for cruising at the speed limit. Try and gear your 5th for that. For my Rover motor that's about 2450RPM @ 100kph.

With a 3.9 diff' the T5 works out quite well with 3.35, 1.99 and .68 and if you really want low RPM at speed irrespective, you can use a 0.63 version.

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Re: Anyone know of a good '79 MGB overdrive transmission rebuilder - Need a new one #9
Peter-Sherman Peter Sherman Melbourne, Australia Sign in to contact 1975 MG MGB V8 Conversion	Mar 31, 2015 10:31 PM Joined 16 years ago 6,513 Posts

I should add the above is based on my using a W58 supra box (0.78 5th) with first a 3.9 diff, then a 3.07 diff. The 3.9 was slightly better. At some stage I'll change it back I think.

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