Diffs, FAQ

[padrickz88]

auto pintara are 4.11's and i got a skyline diff with 3.9's for 50.... just look around i guess and when they ask you if you want axle's etc say no..... less crap the less u pay

but its probably best you go for 3.9's
(looking for a pintara diff cheap for my mate, its doing my head in... all i can really find are skyline diffs lol)

 

[Kernal]

If you change your diff ratio do have to recalibrate your speedo? Does your speedo go out of wack?

 

[Pub247]

If you change your diff ratio do have to recalibrate your speedo? Does your speedo go out of wack?

Yes you do. Most places can do it for you (my mate paid $300 for someone to do it Hahaha) Jaycar do a speedo correction kit. I think Immortality has a how to thread i'll see if i can find it

https://forums.justcommodores.com.au/threads/install-speedo-corrector-kit-vn-vp.60651

 

[Immortality]

gearing for 4.11 diff with 5 speed trans as above with 17" wheels


2400 21.8 35.6 54.9 70.8 98.4
2500 22.7 37.1 57.2 73.8 102.5
2600 23.6 38.6 59.5 76.7 106.6



5000 45.4 74.1 114.4 147.5 204.9
5100 46.3 75.6 116.7 150.5 209.0
5200 47.2 77.1 118.9 153.4 213.1
5300 48.1 78.6 121.2 156.4 217.2
5400 49.0 80.1 123.5 159.3 221.3
5500 49.9 81.6 125.8 162.3 225.4
5600 50.8 83.0 128.1 165.2 229.5
5700 51.8 84.5 130.4 168.2 233.6
5800 52.7 86.0 132.7 171.1 237.7
5900 53.6 87.5 135.0 174.1 241.8
6000 54.5 89.0 137.2 177.0 245.9
6100 55.4 90.4 139.5 180.0 250.0

 

[Disturbed_vegeta]

umm what gears would be good in my stato..having a stock vt ss diff it has 3.07 gears and now that its manual it takes ages to wind out the gears like i can do around 120ish in 2nd..what would be recomended for good bottom end but with not massive drop in eco on 100.

 

[Immortality]

umm what gears would be good in my stato..having a stock vt ss diff it has 3.07 gears and now that its manual it takes ages to wind out the gears like i can do around 120ish in 2nd..what would be recomended for good bottom end but with not massive drop in eco on 100.

it really depends on the manual trans that you have used. with a T5 i'd suggest 3.45 or 3.7's. with a T56 i'd suggest 3.9's or 4.11's

 

[VR38]

small diff question..
got myself set of 3.45's (i have a vr irs calais) inquired bout gettin them fitted, some bloke quoted me $550 cos i need a bit of stuff...im lost?? how so? wat could i possibly need..its the same diff...??
got another quote from pedders to do fitting gears, and mini spool for $330...can i trust pedders to rig it all up properly? they couldnt even align my wheel properly...
lol thats 2 seperate questions... =/

Pretty sure you will find 3.08 and upto but not including 3.45 are the same but when you go 3.45 and over the crown wheel is a different thickness so you will need the matching hemisphere it bolts to.
Same thing happens around the 3.9 4.11 mark from memory.

 

[Pimpn1]

is servicing the diff on a vn easy done or? also what needs doing?

 

[Immortality]

Pretty sure you will find 3.08 and upto but not including 3.45 are the same but when you go 3.45 and over the crown wheel is a different thickness so you will need the matching hemisphere it bolts to.
Same thing happens around the 3.9 4.11 mark from memory.

wrong. the crown wheel and pinions are machined as a set and you should never mix em. you can interchange any BW78 gearset, so 3.08, 3.45, 3.73, 3.89,4.11 will all fit using the same center (keeping the crown wheel and pinion together of course)

is servicing the diff on a vn easy done or? also what needs doing?

simple as draining the oil and re-filling. for VN's you need to remove the entire diff cover to drain the oil, from VP onwards (and maybe some late VN's) the bottom bolt drains the oil. diffs that have the drain bolt can be identified by the larger bolt used on the lowest hole on the rear cover. if you have a LSD make sure you use the correct oil type

 

[padrickz88]

Pretty sure you will find 3.08 and upto but not including 3.45 are the same but when you go 3.45 and over the crown wheel is a different thickness so you will need the matching hemisphere it bolts to.
Same thing happens around the 3.9 4.11 mark from memory.

not true my 3.9's went in fine