Dana 44 4.09 ring gear thickness

I am not sure where you are going with this, but a 4.09 for a 44 is a

4.09... there is no thick or thin version. They (ring gear) have to be matched to the pinion and carrier... there is no mix/match strategy.

-- JimG

80' CJ-7 258 CID 35" BFG MT on 15x10 Centerlines D44 Rear, Dana 30 Front. SOA 4.56 Gears, LockRight F&R Dana 300 w/4:1 & Currie twin sticks Warn X8000i w/ dual batteries

Jeep Rubicons come from the factory with thick 4.09 ring gears (presumably Dana Spicer) to fit their 3.73-sized air lockers. I have a Rubicon locker that's going in my XJ Dana 44 as soon as I get some gears.

I've got a line on a used Dana Spicer 4.09 set with a 1.6875" ring gear. I have a 3.54 gear for reference that is 1.4375" deep. Accounting for the flange height difference at the carrier break, I'm guessing that the

4.09 may indeed be 'thick'. Just want to be sure.

If anyone knows the height of a non-thick 4.09 ring gear, it would help me confirm.

Steve

L.W.(ßill) Hughes III wrote:

Hi Bill,

My best information is the Tru-Lok sitting on my bench beside an open carrier that I pulled from an XJ D44 with 3.54 ratio. Same flange depth.

Read this blurb from Randy's R&P:

(

) "Randy's Ring & Pinion, a leading supplier of truck and off-road differential parts, announces their distribution of the new Yukon Dana

44 4.88 thick gear sets for the 2003 Jeep Wrangler Rubicon"

"Yukon Gear engineered the 4.88 thick gear to mesh seamlessly with the existing Rubicon lockers, the top-of-the-line Tru-Loc ? air lockers. With the computer-designed 4.88, Rubicon owners can push beyond the limits of the standard 4.10 gear and can move from the 31" stock tires up to beefy 37" tires. The thick ring gear set, made from high-quality

8620 steel, also works well in older Dana 44 rear-ends with a 3.73 & down carrier case, eliminating the need for a new carrier case or locker."

The only disadvantage I can see with the need for a thick ring gear is that they cost a bit more new and are harder to find used. Hassle factor aside, I don't think there are any performance concerns that rank with the C-clip.

Steve

L.W.(ßill) Hughes III wrote:

I, (from the old school) stand corrected. :-)

JimG

Hi Bill,

That sounds pretty grim. When you say crack the housing do you mean the locker/carrier or the pumpkin?

Ford doesn't use carrier breaks in most of their rear ends. Would they be vulnerable to similar cracking?

Everything I've read on the topic is that carrier breaks are used solely to reduce the cost of extra steel required to manufacture thicker ring gears. Wouldn't the progressively smaller pinion head be a greater concern than any increased leverage through a thicker ring gear?

Steve

L.W.(ßill) Hughes III wrote:

Hi Bill,

Well, I guess I can only hope that the Tru-Lok is sufficiently engineered to withstand the thicker ring gear. This article:

quotes Jeep engineer Jim Repp as saying that the Tochigi Fuji Sanjyo Tru-Lok was chosen for the Rubicon "because they were the only ones we couldn?t break".

It does get worse though. I just got off the phone with Randy's R&P to get a quote on aftermarket thick gears. It seems the Tru-Lok uses smaller diameter ring gear bolts than what are found on a standard Dana

44 carrier. Sounds like another weak point.

Unfortunately for me, the aftermarket thick gears are threaded for the standard size bolts and require bolt thread adapters to fit the smaller Tru-Lok bolts. Grief. They do supply a thick 4.88 gear that is threaded for Rubicon bolts, but their thick 4.09 and 4.55 gears are not.

I'll avoid the aftermarkets and look for original Rubicon gears.

Steve

L.W.(ßill) Hughes III wrote:

Hi Bill,

This link from an earlier post on this thread states pretty clearly that the Rubicon diff is sized 3.73 & down:

Can't find any official documentation. Rubi owners do mention it:

I should correct a statement I made in my last post regarding bolt thickness. When I said the Tru-Lok needs thinner ring gear bolts, I got it backwards. It actually needs thicker bolts. I hadn't noticed til I checked right now, but the bolt holes on the flange of my Tru-Lok are wider than those on my stock open carrier. So, the adapters (spacers) that the R&P vendor told me about are for the flange holes, not the bolt threads in the ring gear.

Steve

L.W.(ßill) Hughes III wrote: