Need Help With Gear Install

[vcode70]

I just picked up a set of 4:56 gears for my '14 Hemi RCSB 2wd. I would like to install them myself and my mechanic buddy is going to help me out. I was just wondering if anyone knew where I could get the information I will need for the install, such as backlash, pinion depth, and torque specs. Any information you can offer would be greatly appreciated!

 

[RLJ10X]

I'm sorry, Vcode, I'm useless. From what I gather, it's a fussy/critical job. I paid someone to do mine for me. In my case, it was money well spent.

But I am curious:

Which tranny? I assume the 645RFE.

What gears did you start with?

What size tires?

I'm interested in what your thoughts are after the install. Good Luck, My Friend. Check back when you can.

 

[GoldDot]

Google: Safety Recall N08 / NHTSA 13V-038 Rear Axle Pinion Nut

Its for 2009-2012 but may work.....no guarantee tho

 

[vcode70]

I'm sorry, Vcode, I'm useless. From what I gather, it's a fussy/critical job. I paid someone to do mine for me. In my case, it was money well spent.

But I am curious:

Which tranny? I assume the 645RFE.

What gears did you start with?

What size tires?

I'm interested in what your thoughts are after the install. Good Luck, My Friend. Check back when you can.

Usually I like to do the work myself, but this would be my first gear swap so that's why my mechanic buddy is going to be helping. He's been a tech for 15 years, but hasn't done a ZF diff before. My truck is a 2wd with the six speed, I'm currently running 3.92s and my street tires 305/45/22 (just under 33" diameter).

The truck started off life wife 3.55 open diff, then after 1500 miles, I found a complete diff with only 3000 miles on it with the 3.92s and LSD. That was a real easy swap, just changed the whole diff. and sold the original one complete with emergency brakes and all.

 

[Tach_tech]

For specs such as backlash, use whatever the manufacture of the gears recommends. Usually for factory rear ends, 0.005-0.008" is the spec I believe. Bearing caps are 100ftlbs. Side adjusters are 75ftlbs. You're going to need the special tools to set the backlash though. Not sure where you will get those.

 

[vcode70]

For specs such as backlash, use whatever the manufacture of the gears recommends. Usually for factory rear ends, 0.005-0.008" is the spec I believe. Bearing caps are 100ftlbs. Side adjusters are 75ftlbs. You're going to need the special tools to set the backlash though. Not sure where you will get those.

Thanks for the help. That's the thing, the box with the gears doesn't have any paperwork at all and I'm having a hell of a time finding any kind of information online.

 

[jwheeler]

What brand of gears? Maybe call the place you got them from. The specs listed by Tach_tech Will probably work just fine though.


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[vcode70]

What brand of gears? Maybe call the place you got them from. The specs listed by Tach_tech Will probably work just fine though.


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Tried this with no luck unfortunately. Did anyone do this swop themselves? Any info would be great!

 

[jwheeler]

What brand are they? I just got in a set of 4.56 motive gears today. I will be installing on Monday.


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[Tach_tech]

Honestly if it was me doing it in my truck I would be pretty comfortable setting backlash anywhere from 0.005-0.010". As long as you're in that ballpark with a good pattern, you'll be fine.

 

[avantiguy]

I've done a few GM and Dana units but never a ZF. Let me recommend that you Google around for the install if you can't find it elsewhere. The biggest issue is getting the gears to wipe in the correct pattern and that is set in several ways depending on the manufacture of the rear end.

The gear manufacture should be making them to spec so the install instructions should be the same based on the rear end Mfg. Try youtube and Google and you should find what you need.

If you can't find it, a decent mechanic that has done rearends should be able to look at it and see how to do it. The problems arise if special tools or case spreading is required.

You have the assembly in front of you when you open the case so pay attention to what is where before you take them out. Also record back lash and other dimensions before you remove the gears. Take pictures of the wipe and assembly and reproduce it upon reassembly. If it works now those dimensions should be good for reassembly.

If you don't get a good wipe, don't reassemble it and install it.

If all else fails, have someone that knows how to put it back together do it. That's cheaper than the alternative.

 

[vcode70]

What brand are they? I just got in a set of 4.56 motive gears today. I will be installing on Monday.


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There the Moe's Performance gears for the ZF.

 

[cptwing]

There the Moe's Performance gears for the ZF.

Did you ask or talk to Matt? If he is selling them, he should have or be able to get you any information you need.

 

[Rustycowl69]

nobody addressed the pinion depth question. Years ago, oem would have a + or - and a number etched onto the business end of the pinion which you would interpolate with the etched number of the new pinion to Calc the shim change behind the larger pinion cone. If they don't have that etching, then I would just start with the same pinion depth measurement and use trial and error to get the proper pattern. If you buy two sets of pinion bearings and hone the ID a couple thousandths bigger, you can pull/push the cone off/on by hand to facilitate the trial and error procedure. If it were for a Chevy or a Furd 9", you can probably buy a setup bearing already honed out, but I don't know about the late model stuff, because I haven't done any in many years.