have hit a dilemma with my 3.7 diff

Post by **ssnjimb** » Thu Oct 22, 2009 10:46 pm

Hi Folks

I cannot decide what to do.

The midget i have has a 3.9 diff

The 1098 minor has a 4.22 diff

As you know i have purchased a 3.77 differential.

Should the midget get the 3.77 and then should the minor have the 3.9

Jamie

linearaudio · Post by **linearaudio** » Thu Oct 22, 2009 11:26 pm

DIFFerence between 3.77 & 3.9 is around 3 1/2 percent- not a great deal! I would stick the 3.77 in your Mog and save some work & the recalibrating of the Midget speedo

Post by **bmcecosse** » Thu Oct 22, 2009 11:27 pm

I agree! At least there is a suitable speedo for the Minor - dunno about the Spridget.

Post by **ssnjimb** » Thu Oct 22, 2009 11:33 pm

i think the last 1500's had 3.7 diffs though not sure and the speed's are a different design anyway.

Do i just undo and slide out the half shafts and unbolt the diff and prop and then remove the diff then put the new one in and re slide the half shafts back in.

Jamie

linearaudio · Post by **linearaudio** » Thu Oct 22, 2009 11:41 pm

Yes, but if that's too easy for you, you could try it in the dark on a gravel driveway! Sorry, you just sounded a little disappointed at the simplicity of the job

Can't remember on the Moggy, but if you have an access hole for the backplate bolts in the hub, then it makes undoing them much quicker, using a 3/8" drive socket. It's the prop bolts that try me- not difficult, just tedious!

Post by **ssnjimb** » Thu Oct 22, 2009 11:43 pm

lol i also have a brake hose to replace while iam there its floppy and feels like its going to crumble. Iam just worried about undoing those screws on the half shafts tried once before and they would not budge

Jamie

Post by **GeorgeHurst** » Thu Oct 22, 2009 11:50 pm

Jamie you mention that the later Midget 1500's had 3.7 diffs, do you know what an R reg ('76-'77) 1500 would have?

My brother has one that he is getting rid of and I want to nick the diff from it. Do you think I could whip his diff out and replace it with my diff, 4.22?! (My car is a 1098cc 1966 saloon).

It sounds like a simple job and certainly is cheaper than buying a new diff

Post by **ssnjimb** » Thu Oct 22, 2009 11:53 pm

according to google the 1500's had 3.7 diffs.

I would swop it anyway. if its a 3.9 you have still gained

Jamie

Post by **GeorgeHurst** » Fri Oct 23, 2009 12:00 am

Yes good point

Would it make a serious difference to the Midget if I were to put my diff in? It is an MOT failure so probably won't go for much anyway, I just don't want to make it unsaleable for him! As long as it can be driven away...

Post by **GeorgeHurst** » Fri Oct 23, 2009 12:09 am

p.s. apologies for hijacking the tailend of this thread!

Post by **mike.perry** » Fri Oct 23, 2009 12:59 am

Don't forget to drain the oil!!!!!!!!

Post by **ssnjimb** » Fri Oct 23, 2009 10:04 am

Use the diff George if its an mot failure find out if its going to the scrappy. if it is change the diff you can only gain. or someone else will get that diff.

Jamie

Post by **GeorgeHurst** » Fri Oct 23, 2009 10:13 am

Indeed, I will see if a cool £50 would secure it with my brother

Cheers, George

Post by **bmcecosse** » Fri Oct 23, 2009 11:18 am

Swap the diff -no-one will ever know - not even your brother!
As for doing the swap - it is indeed very easy - but best to pull the shafts right out and take the oportunity to inspect the splines. If showing any undue wear - or twist - they may be ready to snap!

Post by **GeorgeHurst** » Fri Oct 23, 2009 11:25 am

Excellent, that is EXACTLY what I wanted to hear!
Cheers, George