3.9 Diff

Post by **d_harris** » Mon May 18, 2009 9:45 pm

Having purchased a 3.9 Crownwheel and Pinion from someone on here not so long ago I thought it was time to give it a go....

Unfortunatly didn't do a howto but it was pretty straighforward to swap them over but with luck more than judgement its dead quiet until you hit ~65 when it sings a little, but to say that I am chuffed is a proper understatement!

Post by **bmcecosse** » Mon May 18, 2009 9:57 pm

Have you figured out what tpm speedo you need - to get accurate speed/mileage readings ?

Post by **d_harris** » Mon May 18, 2009 10:07 pm

I've got a 1376 (I think) which is the speedo for a 4.55 in at the moment which reads about 10% quick. I reckon a 1408 would be nearly bang on....

(remember I have the 13" wheels....)

Post by **bmcecosse** » Mon May 18, 2009 10:25 pm

1408 certainly common enough - not come across a 1376 before - what car is it from ??

Post by **d_harris** » Mon May 18, 2009 10:26 pm

Well, I have 2 in the car at the moment. One is a mini one. The other from a crossover 1098... (i.e 1098 engine 4.55 diff)

Post by **bmcecosse** » Mon May 18, 2009 10:34 pm

Ahh - thought 4.55 diff would be 1508 speedo - that's what came out of mine - and it was very accurate - with 14" wheels/155 tyres.

Post by **mike.perry** » Tue May 19, 2009 12:52 am

A 1408 is accurate with my 3.9 diff and 175x13 tyres.