Gearing AMC 20 from 2.72 to 4.56 Questions

[wagoneer84]

I have an 84 wag with amc 20 rear dana 44 front. I am running 35" BFG's with the 2.72 gears and i am going with 4.56 gears. I have a carrier for the 44 but still need to get one for the 20. My biggest problem is i do not have the pinion depth gauge. Does anyone have any experience changing the ring and pinion without this tool or any suggestions on where i could get one cheap or rent one? The 2.72 with 35's are killing me

[tedlovesjeeps71]

I feel your pain on the gears. Mine on 33s is sad so I can only imagine 35s.
If you have no experience doing a gear set up you'll want to find someone that Does. Especially on the rear that is always used, a good pattern is vital if you don't want to be buying another gear set shortly. Get on every jeep board/club in your area and see if anyone local to you has the skills. They are likely to have the tools as well. If not, suck it up and pay a pro to do it.


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[Stuka]

You can do the R&P without a depth gauge, it just takes longer. As you have to put the carrier in, check pattern, then pull it out, pull the pinion out, change shims, etc.

Hopefully somebody else makes 4.56 gears for the M20 now. Back when I did mine I had to use Genuine Gears (now called G2), and they deserved their nick name Genu-whine, as mine do at certain speeds. And the pattern is perfect.

I ran 2.73's for about 2 months with 34's before going to 4.56. It was HORRIBLE.

These days I pay a local shop to regear my stuff. Its just more work than I feel like doing, as they get it done quick, and it takes me a day per axle.

[SJTD]

Seems to me I've seen a set in the Summit catalog for around $100.

[rocklaurence]

Most of the set-up variations are in the housing. The gears and carrier are machined to Exact dimensions. So, in most cases the original shims on the pinion and carrier will get you there-or real close on the new gears [the shims are needed to correct Casting vairiations in the housing]. You'll want to invest in a good bearing puller/tool [$400] to remove bearings without damaging them. Also, your mesh pattern wont look like the Perfect example they show you in the book. A good pattern is when the gear contact isn't touching any of the 4 edges. Set the Backlash and preload as discribed and you'll be fine.

[Stuka]

Most of the set-up variations are in the housing. The gears and carrier are machined to Exact dimensions. So, in most cases the original shims on the pinion and carrier will get you there-or real close on the new gears [the shims are needed to correct Casting vairiations in the housing]. You'll want to invest in a good bearing puller/tool [$400] to remove bearings without damaging them. Also, your mesh pattern wont look like the Perfect example they show you in the book. A good pattern is when the gear contact isn't touching any of the 4 edges. Set the Backlash and preload as discribed and you'll be fine.

The ring and pinion are precise to an extent. The end of the pinion should have a number stamped in it. A +4, or -2 or something. This tells you how much off zero it is for depth.

[derf]

You can find Yukon and USA Standard gear sets for 4.56 in stock at Randy's Ring and Pinion for the AMC20.

I've never used a depth gauge when installing the few gear sets that I've done. But I've done the "assemble, check the pattern, disassemble, swap shims, reassemble..." game on all of them. It's not overly hard. Just a little tedious. I've never had to do any shim pack adjustment more than 4 times. And on the one that took 4 times, I made an 0.001 overall adjustment to get a pattern from "good enough" to "dead on balls accurate" because why not as long as you're in there.

I don't know about the AMC 20 but the Wagoneer D44 is really pretty easy given that it doesn't have a crush sleeve. Even though I can do gears, I don't like dealing with crush sleeves so that's work I farm out to a pro.

[Stuka]

The AMC20 does have a crush sleeve that is used for bearing pre-load on the pinion.

[SJTD]

It was Jegs that has the pinion setup tool.

If the gears you take out have the markings can you use those and the numbers on the new set to compute the shimming required on the new set?

Or are those numbers to be used with the pinion depth tooling.

Never done it. Read up on it a few years ago but I don't remember the details. Going to do it if I ever get mine on the road.

[Stuka]

It was Jegs that has the pinion setup tool.

If the gears you take out have the markings can you use those and the numbers on the new set to compute the shimming required on the new set?

Or are those numbers to be used with the pinion depth tooling.

Never done it. Read up on it a few years ago but I don't remember the details. Going to do it if I ever get mine on the road.

Those numbers will get you very close. So typically a good starting point.

[wagoneer84]

Thank you everyone for your answers. The ring and pinion i have is motive gear. Since i need to buy a new carrier does using the original shims getting me close still count? Some of the tools i have seen for around $100 do not mention AMC so i was not sure if they would work. I have done the check pattern method before but it was for an off road only vehicle and i didn't know if this would be good enough for the Jeep. It's not my daily driver but i do want to start driving it more. I have had 35" tires on it for around 8 years now but have just mainly used it for going to the desert.

[derf]

Using new shims the same thickness as what came out is always the best place to start, regardless of which carrier you go to.

But that only gets you close most of the time. You often have to do a couple of adjustments but usually not by a whole lot.

I've done the pattern check on two sets of axles. One of them has around 1,000 miles on them so far and is working great. The other has a good 45,000 miles on them and is holding up just fine.

[wagoneer84]

Most of the set-up variations are in the housing. The gears and carrier are machined to Exact dimensions. So, in most cases the original shims on the pinion and carrier will get you there-or real close on the new gears [the shims are needed to correct Casting vairiations in the housing]. You'll want to invest in a good bearing puller/tool [$400] to remove bearings without damaging them. Also, your mesh pattern wont look like the Perfect example they show you in the book. A good pattern is when the gear contact isn't touching any of the 4 edges. Set the Backlash and preload as discribed and you'll be fine.

Wouldn't it be cheaper to just buy new bearings? I have seen the master install kits for around $110

[rocklaurence]

Check to see if you can purchase a Thick/Fat ring gear instead of a carrier--it'll save you some money. Dana stopped the "2 carrier-break" system on the D44s a while back. They now use a thicker gear instead of a separate carrier as used on the Redeo and JK axle and I suppose all the others.

[derf]

Check to see if you can purchase a Thick/Fat ring gear instead of a carrier--it'll save you some money. Dana stopped the "2 carrier-break" system on the D44s a while back. They now use a thicker gear instead of a separate carrier as used on the Redeo and JK axle and I suppose all the others.

They also limited the range of gears available in the axles. The JK D44 only goes from 3.21 to 5.38. The earlier generation went from 2.72 to 5.89.

[Stuka]

He needs a carrier for the rear regardless. The AMC20 range goes from 3.07 to 4.56. The 2.73 carrier won't work, and there are not thick gears for AMC20s.

But for the front, thick gears are definitely an option. But if the spider and side gears are badly worn, may be worth replacing it anyway.

[derf]

He needs a carrier for the rear regardless. The AMC20 range goes from 3.07 to 4.56. The 2.73 carrier won't work, and there are not thick gears for AMC20s.

But for the front, thick gears are definitely an option. But if the spider and side gears are badly worn, may be worth replacing it anyway.

It's also an opportunity to upgrade. When I did the axle swap in my XJ I went to limited slips in both axles as long as I was crossing the carrier break.

[wagoneer84]

I recently installed an EZ locker from CL new old stock for $100. At the time i wasn't planning on doing the gears But it really needs it. As for the front i have not bought the ring and pinion for that yet, i will look into the thick ring gear.