Carrier for new gears.

I have a question for you guys. I have converted from a D25 to a D30 front axle. My D44 in the rear has 4.27 gears and the D30 up front has 3.54 gears. Don't worry, I haven't engaged the front axle to drive yet. I am planning on changing the D30 to 4.27 gears and was wondering if the carrier for the 4.27's in the old D25 will work with the D30? Even better, would the 4.27 gears from the D25 work in the D30? I am a bit uneducated on the similarities/differences between the two axles and this may be a totally absurd question.
Thaks for any input you can give.

 

No and No. also you will need a new carrier for the 30 since you are going past the carrier break point.

 

Thanks for the input. I was afraid that was going to be the case. I thought I'd ask anyway.

 

On the bright side, carriers can be had pretty cheap.

 

I am doing the same thing except going to match the rears 5.38. Do all dana 30 carriers interchange? Say, a carrier from an 88reverse rotation XJ to a 76 regular CJ axle?

 

Can someone explain how to tell the difference in carriers? I recently bought one and was told it was for the lower ratios. But when I set it next to a carrier that had 3.54 gears in it they look exactly the same.

Thanks.

 

I was thinking about this a while back and was told "no" due to crush sleeves instead of shims, although I see some part numbers in catalogs that appear the same across the board.

 

When you have lower gears, the pinion gear gets smaller. I.E. A 4.11 pinion gear is smaller than a 3.73 pinion gear. Smaller to the point that you can't shim the ring gear over enough to get it close enough to the now smaller pinion gear to engage properly. So what the factory does once the gears get low enough to make the pinion that small is they make the differential case with a thicker surface where the ring gear attaches to. That moves the ring gear over close enough to the pinion gear to engage properly.

Sometimes you can buy an extra-thick ring gear for installations on a higher geared case. That does the same thing, helping it get closer to the pinion.

 

CJ-x is correct but I think you ment to say carrier when you said case.:iagree: I have heard the thick ring gear or the shims can give you problems with the bolts braking or comming out. I dont know if that is true or not.

 

Case is the part the ring gear bolts to that houses the side and pinion gears. The carrier is commonly called a pumpkin, third member, chunk, etc. It houses the ring and pinion, case, etc. This is a common mistake made by even people in industry. No problems with the thick ring gears with the bolts loosening assuming everything is assembled correctly. I've seen lots of sets of bolts come loose when spacers are used. Nickmil

 

So is there a measurement that I can take to insure I have the correct case for a lower gear set? The new ring gear I bought is definitely thicker than the original 3.54. When I set the cases on the ground, with what would be the mounting surface for the ring gear facing up, there is a very slight difference in the height of this surface (maybe 1/16").
If the case is incorrect for a lower gear set will it physically not fit or will it just cause major problems ($$$)?
Thanks.

 

It would not fit, you'll need to get a case for 3.73 and higher numerically gears. The 3.54 carrier will not work for the 4.27s. because of the case difference(thick ring gear versus thin).

 

Stephen,
If you install lower gears (higher numerically), on your higher geared case, they will physically fit, but you will not be able to get the proper pattern when you set up your ring and pinion depth & backlash. Your gears will not last. I can not remember how much thicker the ring ger mounting surface is, but I do remember it was noticeable. You said when you set it on its side there was a 1/16" difference. If you have different manufacturers, that difference could be in the bearing mounting surface. I am thinking it was more like 1/8". Those low geared pinions get pretty small. I don't need to change any differential fluid, so I am not pulling off any covers to check.

Most but not all standard gears are thin gears. Fortunately, the Rubicon and some others have increased the market for thicker gears to run on the thin cases.

And ditto on the differential case being what holds the gears, and the carrier being what supports (carries) the differential case; IE the carrier is the pumpkin casting.