Cop Car and SHO geared the same?

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Billy VK

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Does anyone know what the rear end gear ratio is in the police cars? Found a place that has a rear diff out of a cop car that has 20k miles on it but not sure what the ratio is. Thanks again in advance.
 

Billy VK

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IIRC.....

SHO's w/ Non-PP = 2.77
SHO's w/ PP = 3.16
PI EB = 3.39

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So I need to make certain that the replacement I get comes specifically out of a non police, non pp car.... this should be a fun hunt... thanks for the info.
 

Billy VK

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Wait, that is the trans final drive gear, not the rear end gear... correct?
 

krewat

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Isn't the RDU a 1:1 ratio? Because the PTU takes power from the side of the differential unit that's already been geared-down?

The real differences in the RDU are clutch-pack based... The PI has some sort of uprated clutch pack, and I'm not sure if the "regular" PCM will regulate power to the rear correctly.
 

Billy VK

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Isn't the RDU a 1:1 ratio? Because the PTU takes power from the side of the differential unit that's already been geared-down?

The real differences in the RDU are clutch-pack based... The PI has some sort of uprated clutch pack, and I'm not sure if the "regular" PCM will regulate power to the rear correctly.
Yeah, I'm lost there too.
 

Billy VK

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Yes.

I had a long shift last night and just woke up when I posted that.

Sorry about that.

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All good. So no worries of being that specific, they would all be the same as far as that piece?
 

mrhighcaliber

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I believe all of the rdu's are a 2.93 ratio. But The final drive in the trans is what governs the final drive ratio (2.77, 3.16, 3.39)

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stripSHO

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From the input of the PTU to the output of the rear differential has to be 1:1, so I can't imagine there being any gearing differences in the RDU across models but it's hypothetically possible. As stated, the PI does have a more heavy duty wet-style clutch pack and I want to swap one in for that reason. I doubt the electronics will be able to tell the difference
 

Billy VK

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The 3.39 is in non-ecoboosts with 6f50 transmission. Much thinner/weaker gearsets
Yeah, but I think again that is the front end of the car. PTU not rear end differential. I'm just needing to make sure that if I order a rear diff from a salvage yard that the gear ratio in it can't possibly be possibly different.
 

FiveLeeter918

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haha was just about to say, final drive is still in the transmission... RDU is 1:1 whew
 

Billy VK

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So the rear diff is the same for all the cars, whether cop car or not, when they have awd, correct?
 

merp

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From what I've read from the various AWD threads and the EB forum, the PI RDU has a wet clutch versus the non-PI's dry clutch.
 

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