Gear oil

Hi all I am meant to put 80w/90 oil in my diff.
Would it matter if I put 85/145 in????

I am no expert on diff oil but if 90 is spec'd, perhaps that's the one to use. 145 will be thicker and may(??) add resistance to the drive, especially when cold and anything that adds resistance will put extra load on parts, mpg, etc?
It may not be that crucial, but God knows we are running fragile enough vehicles as it is so we should at least use the recommended kit to lessen the chance of any unneccessary breakage.

However, wait a while as I am sure somebody will know for sure:5bseeya:

Hi

Exactly for the reasons Dougden stated, use the correct specced gear oil