MPE Machined 9.25ZF LSD - Bring on the 4.56 Gears!!

[Hemi450hp]

Want to run 4.56 gears in your 2011-up Ram truck? No problem. Modern Performance Engineering is now machining new Mopar Limited Slip Differentials to accept the bolt pattern of the older 9.25 gears. This means that all you need to install 4.56's on a 2011-up Ram truck is this machined LSD and a set of the Motive 4.56 gears. I have been running this exact setup in my crew cab for months now, and it runs perfect.

These are now in stock and ready to ship for only $625 with FREE SHIPPING!! Check them out at the link below...

Modern Performance Engineering Machined Limited Slip Differential for 2011-up Ram 1500 9.25ZF Axle

 

[BigSloth]

Awesome.

But I think that is a tad too much gear for an 8 speed, so not something I'd be buying, but good news for a lot of folks.

 

[Hemi450hp]

I have about 10-15 8 speed customers running 4.10's with great results so far, but don't know of anyone that has attempted 4.56's. I'm hoping to get 1 of my locals to give it a shot just for fun. We cant rule it out until it has been tested.

 

[sicmadek]

Will you possibly do cores with the factory lsd we already have?

 

[RLJ10X]

I could see 4.10s in the 8. That top gear is the same as our 545RFE; which means at 70 mph, the engine is spinning just 2000 rpm. My 545RFE/4.10 does the same on gas as what my truck did when it was bone stock, I believe. But, I don't spend a lot of time above 65 mph, so I don't know what happens up there. Not saying it's worse, just don't know. 8/4.10, why not?

The 8/4.10 guys would be able to give some insight into what 4.56s would be like. I'd like to hear what an 8/4.10 is like anyway....

 

[RamRT]

I wouldn't mind throwing the 4.56 in my R/T . It's either gonna snatch like h*** or break. Either way I could always go back to the 3.92s.

 

[Hemi450hp]

Will you possibly do cores with the factory lsd we already have?

I'll have to talk to MPE about that. I don't think they want to mess with a core program because these units we are offering are brand new from Mopar. There is not a clutch rebuild kit available for the ZF rear, so if a customer sent in a core with worn clutches, it would be nothing but a paperweight.

It should be very easy to sell your used OEM LSD though.

 

[BigSloth]

I could see 4.10s in the 8. That top gear is the same as our 545RFE; which means at 70 mph, the engine is spinning just 2000 rpm. My 545RFE/4.10 does the same on gas as what my truck did when it was bone stock, I believe. But, I don't spend a lot of time above 65 mph, so I don't know what happens up there. Not saying it's worse, just don't know. 8/4.10, why not?

The 8/4.10 guys would be able to give some insight into what 4.56s would be like. I'd like to hear what an 8/4.10 is like anyway....

It's not the top end I'm worried about, the difference in the 8 speeds isn't that they have different ratios up above direct drive, it's the 6 gears it takes to get to direct 1:1 drive. In my 8 speed with 3.21 gears, 1st and second are over in a flash at part throttle. I can't imagine that with 4.56s. I tell you one thing though, if it could hook up, it would put out one hell of a 60' time.

 

[DavidRam]

"... lead me not in to temptation!"

Would the 4.56s make a big difference over my 5,000 mile old 4.10s/lsd???

 

[BigSloth]

I ran some calculations.

First gear in an 8 speed is a ridiculous 4.714:1, second is 3.143:1
Assuming my tire size of 31.5", and diff ratio of 3.21, that puts me at 36mph at 5800rpm at the end of first gear, and 57mph at the same rpm end of 2nd. Changing that ratio to 4.56, leaving all other factors the same, turns that into 25 mph at the end of first gear, and 37 mph at the end of 2nd. That's wide open throttle. 2 shifts before you hit 40.

 

[Hemi450hp]

"... lead me not in to temptation!"

Would the 4.56s make a big difference over my 5,000 mile old 4.10s/lsd???

Not worth the swap with you already having 4.10's. You just need to break down and buy that dang tq converter already...haha.

 

[bigolayne]

I want to swap out of my 3.21 so bad I can taste it. But, with this dang 4x4 it's a total axle swap up front and then doing the rear, big $$$, but as I have been told, you have to pay to play. So if you know of anyone wanting to swap let me know!!!!

 

[BigSloth]

Not worth the swap with you already having 4.10's. You just need to break down and buy that dang tq converter already...haha.

Do iiiiit. The 2800 edge/sharadon valve body was the best thing I ever did to my 06.