diff change

[aza03]

hi just wondering if a 3.73 diff would be to high for my v6 auto to handle. i have read other tread that say 3.46 is a good upgrade but just wondering if the 3.73 is any good

[jazza15]

The VY v6 did not come out with 3.73 or 3.46/5 diff gears, so you can't say it was designed to have them.
The v8 used the 3.45/6 diff gears, but that was with a different engine and transmission combination.
As to whether it will do you car damage long term, only time will tell, or few few people will who have fitted the particular ratio that you are after.
Personally I wouldn't just take 1 persons word for it saying "yeah no worries at all".
With the increase in ratio comes an increase in acceleration at the sacrifice of top end speed. So as you may have already read, your car will sit at higher RPM when cruising on the freeway at 100km/h.

[VTPREDATOR]

by not coming standard with those ratios, does not mean that its not designed for it.

[VYFORI]

GDAY MATE....

I have a manual VY V6 with a getrag T5.. it has 3.46 gears its just perfect..
You should have no worries with an auto but you might have to change the autos
shift points......

The 3.7s might be a bit tall you will have extra acceration but no top end plus if you
do alot of freeway miles then answering you question you engine wont last long sitting
at high RPM for long periods of time IE... 1000km travels +

My 2c mate

RIK....

---

[a1k3m1]

any idea what type of RPM it will sit at on the freeway? . . mine does just under 2000 with a stocky one.... thanks

[Vt_vic]

id go 3.7 or 3.9 i know loads people who love the 3.9 in ecotecs autos

[wana s' charge stock vt]

what happens to the shift points if ya change diff gears????? is it a must to hav the shift points changed???

[danja]

A lot of people say there isn't much noticeable difference between 3.08 (stock) and 3.46, so if you're going to spend the money you may as well get a 3.7 or higher set.

3.08 is definitely at the "economy" end of the spectrum when you match it up with the 4L60E - you ask can the V6 handle 3.7/3.9, well sure it can, the only real consideration is that with 3.73's you'll be revving 20% higher given the same gear and road speed. Go for a drive on roads you frequent, and think to yourself "how much would I care if I was doing 2,400 rpm right now, instead of 2,000?"

I had a mini rant on diff gears a while ago: Diff Gears, How they affect acceleration

[Calaber]

Some of you guys need to understand what "higher" ratios means when talking about gearing. The greater the number, the lower the ratio, not the higher. Tall diffs have low numbers, such as 2.78 or 3.08 and lower ratio diffs have 3.73, 3.9 etc.

Fitting a 3.73 into a standard Ecotec/auto will simply mean faster accelleration, lower top speeds in each gear, greater engine noise and wear and, depending on driving habits, greater fuel consumption. Your speedo will need to be recalibrated or it will read approx 21% fast as Danja points out. You wouldn't need to "change the shift points" in the auto, as maximum speed in gears will be determined by engine revs.

[Raczy]

All you need to do its calculate the PPK (pulse per kilometer) value, which is an engine cal.
This can be done at any holden dealer who knows what they are doing, with a tech 2 computer.

[colgf]

A lot of people say there isn't much noticeable difference between 3.08 (stock) and 3.46, so if you're going to spend the money you may as well get a 3.7 or higher set.

3.08 is definitely at the "economy" end of the spectrum when you match it up with the 4L60E - you ask can the V6 handle 3.7/3.9, well sure it can, the only real consideration is that with 3.73's you'll be revving 20% higher given the same gear and road speed. Go for a drive on roads you frequent, and think to yourself "how much would I care if I was doing 2,400 rpm right now, instead of 2,000?"

I had a mini rant on diff gears a while ago: Diff Gears, How they affect acceleration

I have a Dana LSD (Volvo housing) 3.73 ratio in my EH fitted with a S/C V6 & auto combo- At 100kph the tacho reads about 2750 rpm. The vehicle really gets off the line well , wheelspin is apparent when floored.I am VERY happy with this engine/trans/diffcombo. It would be no different in a commodore but the commy is about 300kg heavier than the mighty EH.