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MGB First of probably many questions - driveshaft transplanting:

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YakkoWarner

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I have to transplant my 1970 engine/transmission/driveshaft into a 1973 body. According to the Workshop Manual, before removing the driveshaft you need to make indexing marks on both the transmission output flanges and the rear axle input flanges. This implies that the driveshaft has to go in with a certain alignment (the Manual states "this is most important" in bold print). However, since I am mating the driveshaft to a DIFFERENT axle than the one it is being removed from (same type, but I'm not moving axles between cars), how do I determine the correct orientation? I intend to leave the transmission end attached unless there is some really important reason NOT to leave it attached, but how do I correctly mate it up with the rear axle in the newer car? And what are the potential consequences if it is wrong? The Manual has good explanations of ensuring the front and rear yokes stay aligned to each other (which I won't be disturbing because I'm not disassembling the splined sliding section) but no information on lining up the flanges. They don't look like they have any kind of offset or asymmetry to them which would require a specific orientation but the Manual stresses that point so there must be a reason.
 
Yakko said:
And what are the potential consequences if it is wrong?
Click to expand...


You will feel a vibration at higher RPM. Index the front joint (spray paint and a scribe line) and you've a reasonable chance of getting the rear together with no issues; If you get a vibration from the rear after the job's done, go 90° on the rear flange and try again.
 
I will also say these cars were built by guys named Mick and Angus smoking cigarettes and adjusting things with hammers. The tolerances on these cars are kind of like those found in fieldstone walls - just put it together and drive. :cheers:
 
Since you're not going to separate the two propshaft sections, you'll be fine since there is no chance of changing the phasing...
 
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