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MG Midget and Sprite Technical - bent diff ?

Hi All my new 1275 midget 1969 has really bad vibration worse under heavy acceleration.

If I jack up the back end and and with the car in neutral turn the rear wheels so as to rotate the prop I can see the prop going up and down.

i.e. the input flange to the diff is somehow bent or off center. As I rotate it through 360 degrees the prop goes up and down about 5mm.

Pretty sure its not the UJ as I can see the input flange moving up and down too. Given it a good tug and doesn't seem loose ?

Any ideas, diff seems nice and quite no strange noises.

How could then input shaft get bent ? It is very sturdy. Could it have been assembled incorrectly ?

I am on hoilday now for a week so will take a look on my return. If anyone has a good 3.9 diff then please let me know.

cheers Ben
Ben Brown

It could have been involved in a shunt.

I might have a spare 3.9...I'll take a look.
Dave O'Neill 2

try taking the drive shaft loose at the 4 bolts on the diff and rotoating bolt location 90 degrees and rebolting it back up...not sure that will fix it, but there are 2 ways to bolt the shaft to the diff and only one is correct

while its undone at the diff ...try "gently" to push/pull on the drive shaft and see if it will slide back nd forth in the tranny rear end...You DONT want to remove it, as you will have a god awful mess of oil everywhre if it slips out of the rear of the just want to see if the drive shaft is JAMED in the splines of the tranny...if there is no movement back and forth and the thing is jambed/stuck...then it may have jumped the splines and sitting crooked, causing the issue you have.


Prop The ALL Knowing Spridget Oracal

Hi all, Thanks for the tips. I will take a look and see what I can see.

No sign of a shunt and I think I can see the diff input shaft going up and down as well as the prop.

Probably best bet is a new diff


Ben Brown

This thread was discussed between 12/08/2010 and 13/08/2010

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