ZF6 what gears

Macktruckdriver

Macktruckdriver

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Feb 25, 2008
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Ok so Im putting a zf6 in my truck this year. What gears do you pull in with a zf6 I know the NV4500 you pull 4lo or 2hi but what gears in the zf6 I heard there are 3 options.
 
The ZF6 has the ratios of: 1st; 5.78, 2nd; 3.30, 3rd; 2.10, 4th; 1.31, 5th; 1.00, 6th; .72

That gives you the following ratios that would be useful:

Fourth gear: 1.31 x T-case low: 2.72 x Differential: 4.10 = Final Drive: 14.61

Fifth gear: 1.00 x T-case low: 2.72 x Differential: 4.10 = Final Drive: 11.15

Second gear: 3.30 x T-case high: 1 x Differential: 4.10 = Final Drive: 13.53
 
I don't know what kind of power you're making but that makes some difference.
I have 3.73 gears and normally run 4th LO but ocasionally I'll grab 5th LO.
2nd HI is a good way to break parts from what guys tell me. I've never run HI.
I do know one guy who always runs 5th LO and sometimes 6th LO but he's pushing 950rwhp with his Duramax. I'd be scared of 6th even if I had more power because I have already blown 6th apart once just towing at high power levels.
 
Same here, 4th low has always been my gear, could probally get 5th, I just dont pull enough to try different things!
 
01Duramax6spd said:
I don't know what kind of power you're making but that makes some difference.
I have 3.73 gears and normally run 4th LO but ocasionally I'll grab 5th LO.
2nd HI is a good way to break parts from what guys tell me. I've never run HI.
I do know one guy who always runs 5th LO and sometimes 6th LO but he's pushing 950rwhp with his Duramax. I'd be scared of 6th even if I had more power because I have already blown 6th apart once just towing at high power levels.
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6th lo?:doh: I can't believe his trans is holding up to that? I have also blown the OD out of a ZF6, unloaded, on a steep hill. I can't believe he can get one to stand up to sled pulling....
 
Low 6th pulling with what gears? If it's stock 3.73's and a 33" tire, that's a mid 7's final drive....... even with 5.13's it would be in the low 10's.
 
I believe he is running 4.56's. I doubt he did it more than a time or too. 5th would probably be the gear to use if you're above 650hp. I know there were a few times last season I wish I had tryed 5th.

59Dsul said:
Low 6th pulling with what gears? If it's stock 3.73's and a 33" tire, that's a mid 7's final drive....... even with 5.13's it would be in the low 10's.
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With below 600hp. 4th low and 3.73s works good. Above 600 you need to start thinking about different gears. 2nd high and 3.73s works well but you WILL bust the output shaft off.

4.56 and 5thlow works great for the higher HP trucks. 5th gear is the strongest the trans will ever be. I caution against 6th. On looose tracks it can work but if it hooks up you run a big risk of trashing the entire trans.
 
well we are thinking 4.88 and maby 4.88 5.13 rear. Still doing some research. Im figureing on over 600hp it is a cummins not a Duracrap lol
 
JOHNBOY said:
With below 600hp. 4th low and 3.73s works good. Above 600 you need to start thinking about different gears. 2nd high and 3.73s works well but you WILL bust the output shaft off.

4.56 and 5thlow works great for the higher HP trucks. 5th gear is the strongest the trans will ever be. I caution against 6th. On looose tracks it can work but if it hooks up you run a big risk of trashing the entire trans.
Click to expand...

X2, 4.56's are working good but had to put two more tires out back to get some more traction and boost. Think we will have to run 35's this year to get the traction needed...
 
Thanks for clarifying things John :Cheer:. Hows the truck doing these days? Mine is sitting here broke and begging for more power :hehe:

JOHNBOY said:
With below 600hp. 4th low and 3.73s works good. Above 600 you need to start thinking about different gears. 2nd high and 3.73s works well but you WILL bust the output shaft off.

4.56 and 5thlow works great for the higher HP trucks. 5th gear is the strongest the trans will ever be. I caution against 6th. On looose tracks it can work but if it hooks up you run a big risk of trashing the entire trans.
Click to expand...
 
well for a basic run down of what Im running.......12v of course....head valve springs retainers and keepers big valves in exh side...motor had mahle pistons with .080 valve reliefs and tapered edges big bowls, Billet cam, CDS 12mm pump 600cc no plate, charger gt4202, air to water....probably guna go 4.88's any other input....This is a 2.6 truck
 
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