Outer Limits 4x4 Board

why is that diesels run a lower diff ratio 4.3-4.6 than the same size patrol engine ie 3.9-4.1 when the diesel has so much more torque.
just a corious question in my new diesel build up i am toying with running with 3.9s with 35's and useing 85% crawler gears for of road to achieve the best of both worlds ie cruise on high way and play off road,
any constructive thoughts !

the diesels run a lower rpm

Not sure what you talking about man. Going by your signature I'm guessing we are talking GQ

3.9 in some and 4.11 in manual with TB42 or TD42
RB30 is 4.3 and RD28 has 4.6

i was talking patrol gq gu either way and have i got it wrong !! i thought the td42 was rarely 4.1 for some auto and usualy 4.3 with the td42 occasionaly 3.9 for auto but mostly 4.1 manual or auto.

Our TD42 has 4.1s, putting 3.9 with 35s will make it drive like a dog mate.

diesels are meant to run lower rpms than petrol,gq 4.2d have 4.1ratio 4.2 petrol have 3.9 . the gu 4.2d stil have 4.1 ratio. dont understand what your on about mate.
Im curious to know what the gu 4.8 petrols diff ratios are, i have heard 10 different ratios from ppl which means only one of them know what there talkin about???

ALL 4.2 manual gq's are 4.1 standard
some manual petrol mavs are 3.9
and autos are 3.9

RIZZO wrote:diesels are meant to run lower rpms than petrol,gq 4.2d have 4.1ratio 4.2 petrol have 3.9 . the gu 4.2d stil have 4.1 ratio. dont understand what your on about mate.
Im curious to know what the gu 4.8 petrols diff ratios are, i have heard 10 different ratios from ppl which means only one of them know what there talkin about???

If diesel is the lower reving engine which means the lower reving engine is made to rev harder at high way driving by running the lower ratios why

as for the gu 4.8 i believe the autos are 3.5 and are also only in the h260 larger style diff in the rear and 3.9 for manual.

My 2002 4.2 GU had 3.9s but I changed them to 4.3s when I fitted bigger tires

offroader-rama wrote:

RIZZO wrote:diesels are meant to run lower rpms than petrol,gq 4.2d have 4.1ratio 4.2 petrol have 3.9 . the gu 4.2d stil have 4.1 ratio. dont understand what your on about mate.
Im curious to know what the gu 4.8 petrols diff ratios are, i have heard 10 different ratios from ppl which means only one of them know what there talkin about???

If diesel is the lower reving engine which means the lower reving engine is made to rev harder at high way driving by running the lower ratios why

as for the gu 4.8 i believe the autos are 3.5 and are also only in the h260 larger style diff in the rear and 3.9 for manual.

how sure are you on the ratio's for the 4.8 auto?.....I'm planning on converting a GU 4.8 to a TD42T and need to be sure......any one else know more on the H260 differentials?

regards Garth

Have a look on on the plate on the fire wall, it will say TRANAXLE on it the last two numbers are the diff ratios have fun.

I was lead to believe the following was correct.

GU 4.2's were/are generally 3.9 for the factory turbo wagons. (have owned a 1999, 2002 and 2006)

GU 4.2 naturally asperted wagons may have been 4.1.

GU 4.2 factory turbo utes were 4.1 (owned a 2004)

GU 4.2 naturally asperated utes were 4.3 or 4.6

Though in know way claim this to be true in all cases.

Jason