What cars have 3.7 diff gears

[Vortex-98]

Hey I'm looking to upgrade my diff gears in the AU,thinking 3.7s or 3.9s would be ok..do ba xr6 have 3.7 or xr6 turbo....

[Jack91]

No. 3.45. M78 diff is shared in heaps of commodores and others. Skylines and pintaras are the most common donors for 3.9 and 3.7. They're a bit hard to get now be cause everyone wants them, new gears can be had for $400 all the way up to 4.11. I found a shop in Melbourne to supply and install for $1000

[au350hp]

Originally Posted by Vortex-98

Hey I'm looking to upgrade my diff gears in the AU,thinking 3.7s or 3.9s would be ok..do ba xr6 have 3.7 or xr6 turbo....

Do the maths first so you know what RPM will be at 100km/h.

[josh1990]

You'll find 3.73 gears behind 6 speed manual falcons. However, Turbo and V8 models are M86 and will not fit your housing. As mentioned, you can find the ratios you're after in old pintaras and skylines. But be warned, there are 3.89 and 3.91 ratio from those models. You want the 3.91 as the 3.89 are notorious for whining. I used the 3.89 in my BA and they whined like a banshee. To the point I went back to a 3.45 (I do miss the acceleration though).

[TICKFORD220]

Originally Posted by Vortex-98

Hey I'm looking to upgrade my diff gears in the AU,thinking 3.7s or 3.9s would be ok..do ba xr6 have 3.7 or xr6 turbo....

I got a brand new genuine dana set of 3.9 for my au xr8 for about $500 on ebay,only use genuine dana/spicer gears.
I haven't fitted them yet though $$$$$$

[Nu66et]

Originally Posted by josh1990

You'll find 3.73 gears behind 6 speed manual falcons. However, Turbo and V8 models are M86 and will not fit your housing. As mentioned, you can find the ratios you're after in old pintaras and skylines. But be warned, there are 3.89 and 3.91 ratio from those models. You want the 3.91 as the 3.89 are notorious for whining. I used the 3.89 in my BA and they whined like a banshee. To the point I went back to a 3.45 (I do miss the acceleration though).

Only the M86 cars use 3.73 diff gears with the 2.9/2.6 first gear ratio. Standard boxes have the shorter 3.3 first gear so only got the 3.45 diff ratio

[Vortex-98]

Thanks for the info ...so with the skyline diff is that from the regular 32.33 gts gtr type or the boxy shape earlier one the 31 and what model fords got the 6 speed manual...are these lsd centres

[NCII40]

Originally Posted by Vortex-98

Thanks for the info ...so with the skyline diff is that from the regular 32.33 gts gtr type or the boxy shape earlier one the 31 and what model fords got the 6 speed manual...are these lsd centres

0431557226

Call Glen
He built my diff, he used a VL turbo LSD 4 pinion and 389s from a skyline
I have no Whine in my diff at all

based in Keysborough.

(GJV Automotive)

He has a ebay store too, His username is Vicmelboz.

He specialises in BW diffs

You then need a speedo corrector behind the cluster

If you have an auto then need to follow some instructions i posted on how to get the VSS to talk to the ECU to shift the trans properly

https://www.fordforums.com.au/showthread.php?t=11464112

[josh1990]

Originally Posted by Nu66et

Only the M86 cars use 3.73 diff gears with the 2.9/2.6 first gear ratio. Standard boxes have the shorter 3.3 first gear so only got the 3.45 diff ratio

Correct, can't edit posts after you reread them later though

Supposed to read "You'll find 3.73 gears behind 6 speed manual Turbo and V8 models, however the diffs in these are M86 and will not fit your housing."

The longer first gear with 3.45 gears is a hoot rolling around town though

[Nu66et]

Yeh im running a turbo box with 3.23's

[Interceptor]

fwiw, my BF series 1 XR8 6 speed manual had a 3.45 diff

[Vortex-98]

Is changing just the centres to a higher ratio easily doable....like find a xr6 turbo grab the diff centre ,bolt her in an go do sum hectic donuts an burnouts...

[BOTTLEDUP]

Originally Posted by Vortex-98

Is changing just the centres to a higher ratio easily doable....like find a xr6 turbo grab the diff centre ,bolt her in an go do sum hectic donuts an burnouts...

No. AU & BA onwards are completely different diffs and not interchangeable.