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MG MGA - Yet another transmission question
| My "new" 60 MGA, has what appears to be a twin-cam transmission...This based on the info previously posted about the five different trannys.... So far, I have found a number on the tail-shaft housing...and I would like to know if it means anything? The number is "3274".... The reason I believe it to be a twin-cam tranny, is that it has a flat "boss" on the top of the housing, a heavy rib on the bottom of the tail shaft, and a high starter position, along with the flange on the output shaft.... What other identifying features would there be? If it is a twin-cam tranny, is there any way of knowing if it is a close ratio box? Thanks Edward |
| Edward Wesson 52TD |
| Engage the gears and count the turns in and out! |
| Art Pearse |
| Edward, see if you can drive up to 30 mph in first without the engine exploding - you can with the c/r box. Make up chart for the different gears with roadspeed at different engine speeds taking the diff into acount, and note which ones match. That was how I worked out that my 1500 came with the c/r box. |
| Dan Smithers |
| The "twin cam" transmission seems to be quite common on 1600 MkII best way to see if it close ratio is to engage 1st and count the turns of the propshaft for one turn of the engine. if it's about 3.6 then it's a standard box. |
| Neil McG |
| Edward, Attached is an image of a Twin Cam gearbox. Note that the oval shape must not be an open hole. If the hole is open it is probably a Magnette gearbox. Mick  |
| M F Anderson |
| Edward, Neil seems to have a typo there. For 3.6 turns of the engine the tail shaft turns once on a standard box. For 2.4 turns of the engine the tail shaft turns once on a CR box. Mick |
| M F Anderson |
| Mick Do you know if there is more than one style of twin-cam gear box? Mine has the flat boss on top of the flywheel housing, but no holes drilled in it. Everything else looks the same. Thanks all for the info....Right now, doing some paint matching, so it will be a few days before I can count turns. Edward |
| Edward Wesson 52TD |
| So I went back out to the garage, just to confirm what I am thinking..... While the square "boss" on the top center of the bell housing, is not drilled , like Mick's, it definitely has the high, square shoulder like the one pictured here...it is , otherwise, identical: http://mgaguru.com/mgtech/gearbox/gt101.htm Now I need to get the fill port on the tunnel open , and check the number. Does anyone know if the metal in the gears is any different in these trannys, compared with the standard 1600's? Edward |
| Edward Wesson 52TD |
| Edward, Some Twin Cam gearboxes do not have the two holes in the boss. See attached image. All the internal parts in the pushrod and Twin Cam gearboxes are identical. Mick  |
| M F Anderson |
| "Edward, Neil seems to have a typo there. For 3.6 turns of the engine the tail shaft turns once on a standard box. For 2.4 turns of the engine the tail shaft turns once on a CR box. Mick" Thanks Mick, you are absolutely right! |
| Neil McG |
| "Edward, Neil seems to have a typo there. For 3.6 turns of the engine the tail shaft turns once on a standard box. For 2.4 turns of the engine the tail shaft turns once on a CR box. Mick" Thanks Mick, you are absolutely right! |
| Neil McG |
| Mick Yes, that is exactly like my tranny (photo without holes in the boss). The bad news is that it looks like I need a new clutch... I had thought there was a problem with the hydraulics, but that now doesn't appear to be the situation... Pedal doesn't release until almost the top of its travel. At first I thought it might be air in the line, or a bad slave hose, or slave...But on close examination, all that appears to be working.... Only leaves throwout, disc, and pressure plate. I've only pulled engines/trannys on TD's and B's.... Does anyone ever pull the lump without the tranny, on A's? Or should I just bite the bullet and pull the whole unit? Any clever hints, would be appreciated. Edward  |
| Edward Wesson 52TD |
This thread was discussed between 20/05/2013 and 22/05/2013
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