Does anyone know the max HP or torque inputs for a ZF6 trans? Thanks.

 

I am not sure of the exact rating for this transmission, but I do know that the ZF S6-650 is also used with the PowerStroke and Duramax diesels (with the same gear ratios, too) as well as the GM 8.1L gasser. That would suggest that it is good for 600+ ft*lb. Because horsepower is a function of torque, I would think that the horsepower rating would also be quite significant. I don't have a calculator right handy here to back calculate the horsepower for the revs that the V-10 turns, but I'm sure it could handle engine modifications. I don't know if the clutches used in gas and diesel applications are different, but this could certainly affect the amount of power it is able to handle without being upgraded. Overall, this is a very heavy duty transmission. I know this answer wasn't very clear, but maybe it helped.

 

I wrote the above post thinking I was in the V-10 forum, which explains the bias - but the information is the same.

 

As we all know the factory rates them at a certian number but the real world numbers are a lot diffren't. Are you trying to figure out how much power you can put through the tranny, or how much the stock clutch can handle or do you just want to know the number the factory dreams up? I know the NV5600 is rated at somewhere close to 550fttq, but in the real world it has no problem handling well over 1000fttq. Imput shafts seem to bethe week link, shurly someone is making stronger ones with all the cranked duramaxs and strokers....

 

From ZF's web site:

Transmission type: S 6-650
Input torque max.: 720 Nm (Ft. Lbs. 520)

(Reference value: depending on vehicle data
and application conditions)

Standard ratios Gear:
1: 5.79
2: 3.30
3: 2.10
4: 1.31
5: 1.00
6: 0.72
R: 5.23
Weight without auxiliary: 106.5kg (235 lbs)
Oil quantity: 6.0dm3 (5.8 Qts.)
Oil grade as per ZF List of Lubricants: TE-ML 02;
specification acc. to vehicle manufacturers instructions
Installation Longitudinal with shift output for left or right-hand drive vehicles

These units have a smaller gear set for gas engines so the ft/lbs rating is probably closer to 450 on gassers. Also, from what I've read about these ZF transmission, there is usually a 20% safety margin built in to them so they could handle 624 ft/lbs.

 

This is the information I found too, its funny though. Because the 6.0 puts out 570lb ft of tq, and it is found behind the ZF trans. 50lb ft of tq isnt much of a difference in the end, but you would think that Ford would put a trans in that would handle that much torque within rating. I know the ZF will live behind 600-700 lb ft of tq all day long, but Im going to be pushing a little over 1100 with a Cummins swapped in. I guess Ill just have to be smart about using the loud pedal too much. Thanks for the responses guys.

 

I wonder about that 520 ft*lb rating, also. The Duramax is rated at 600+ ft*lb. Maybe there are clutch differences for the different applications.

n578md said that there is a difference in the gearset for gas and diesel applications. How does this work? The ratios are the same for both. I am curious as to how they can make a smaller gear train and still keep those ratios. Can someone please explain this? Thanks.

 

350hp and 760ftlbs on the dyno and many 4000rpm sled pull launches and mines held so far!

 

I am curious as to how the gear sets differ. From what I have read, it shows the ratios to be the same. I thought that the only differences were the bell housings and input/output shafts for the different applications. I have a buddy with the S6-650 on a 2003 Duramax, and I was hoping that my 2005 V-10 (on order) would have the same tranny. Does anyone have more info on this? Thanks.

 

I just got off the phone with ZF and here's what they told me:

The following years and engines use the "Standard Torque" version:

2002- present Ford 5.4L, and 6.8L
1999 - 2003 7.3L Diesel
2002 - present GM (6.0L) , 8.1L and 6.6L Diesel

All these transmissions have the same internal components minus input shaft differences for 4x2, 4x4, diesel/gas, bell patterns etc... which are rated at 520 Ft./Lbs.

The following uses the "High Torque" version:

2003 1/2 to present Ford 6.0L diesels that is rated at 570 Ft/Lbs.

The difference isn't in the actual component size or design but in the tooth cutting/finishing method used on the High Torque versions which yields a higher torque rating. So the gear set has a "smaller" torque rating on the Standard-Torque version than the gear set on the High-Torque version.

Your friend with the Duramax has the exact same internals as your 2005 V10, minus of course the ATF cooling pump and circuit. (GM doesn't use that feature.) You still have differences in bell patterns, which is integral on these units and you may have differences in input/output shaft dimensions too.

PS: As a matter of course, ZF does not recommend that you exceed 520 ft/lbs for the "standard-torque" S6-650 and 570 ft./lbs for the "high-torque" S6-650...

PS #2: You should have bought a diesel. Real men use diesel...

 

Thanks a lot. That certainly helps clear things up in my head. I appreciate you checking that stuff out. My only question that remains now is that according to the information you quoted, the 2005 Duramax gets the "standard torque" rated S6-650. The rated torque of this engine is 605 ft*lb, which is significantly higher than the 520, or even the 570 ft*lb ratings. The claimed Duramax torque rating is also "when equipped with the Allison 5-speed automatic transmission". Does this make a difference? Are the engine torque ratings different, based on the transmission it is mated to? I hope that I'm not getting off-topic by asking this, but I am just trying to learn about this stuff. Thanks again for the info and explanations.

 

I asked ZF about the fact that the Duramax was rated higher than the 520 ft/lbs input torque of the transmission and they said that so far, GM has not reviewed or changed their requirements and specifications. That can probably be explained by this bit of information taken from Chevrolet's Spider Area for the 2005 model year:


Engine, Duramax 6600 Turbo Diesel V8,

(with Manual Transmissions 300 HP [223.8 kW] @ 3000 rpm, 520 lb.-ft. [702.0 N-m] @ 1600 rpm)

(with Automatic Transmissions 310 HP [231.2 kW] @ 3000 rpm, 605 lb.-ft. [816.8 N-m] @ 1600 rpm)

(LLY) $5,310.00

So it appears that with the 6-speed, the Duramax is detuned to the S6-650's maximum (or continuous rated) input torque of 520 ft/lbs anyway.

 

Thanks a lot, bud. That is quite a surprising stat that I bet not a lot of people are aware of - at least I was not aware of. Do you know if changing engine tuning to fit a transmission or chassis is a common thing? Along those same lines, I believe that GM's 6.0L High Output V8 (345hp) is the exact same engine as the 300 hp version with a different computer. I am assuming that this was done so that the 6.0L motor wouldn't have a higher horsepower rating than the 8.1L.

I appreciate you taking the time fill me in on these details. Thanks again.

 

have you ever noticed the gm has a niceer shifter handle and it shifts more smooth then ares?

 

Never driven a ZF GM truck, I dont see enough of them to even get a chance to drive one. House22, you have a white SD 350 DRW right? I think I saw you at the sled pulls just north of Champaign last winter. Just curious if you have ever dynoed your truck......