anyone running 36 or 37's on the d30

[Beezil]

38s and a basically stock d30 with 4.10s and a gearless locker

not to mention the wear you are putting on your aw-4 ya jackass!


convertor slip creates heat

no lock-up creates heat

lugging creates heat.

heat kills trannies.

i rebuild aw-4's and i aint cheap!

start saving your money.

 

[Gary E]

I don't understand the whole pinion bearing thing, either its turning or its not, I don't see how it matters what gears you are running, I could see how it would be bad for it if you were side loading it but it really only sees a rotational force. I also don't see how it wears your gears in the t-case or tranny, all it does is provide less torque to the axle shaft.

However running too high of gears can be bad on the tranny clutches and put more slippage on the Torque Conv.

Hey Beez at whats the stall rpm on stock xj converter?

and how is running without the lockup working worse than all the other converters that don't have a lock up converter?

one of the first things I added to my jeep was a tranny cooler.

 

[CRASH]

Running CTM's for a daily driver is no real choice (i think, i maybe wrong) so they are still the weak link until you get axle shafts that hold the 1-ton u-joints.

HUH? Lockout hubs equal CTM no-turny....no-turny equal no wear. Jack from CTM has been running his CJ with the front hubs locked for 2+ years, the CTM spinning away every day, with no discernable wear on them at all. So I would say they would be just fine even with an OEM XJ 30, and they would likely outlast your lifetime in a rig with lockout hubs.

60's have their merits, don't get me wrong, but they really only start to become viable when the tire size exceeds 38". That is when you begin to have problems with the balljoints on a 44. Also, at a 38 inch tire size, you'll want to run at least 5.12 or 5.38 gears, which are much stouter in a 60 than a 44. The negatives to a 60 on an XJ, as I'm sure you realize, are weight, ground clearance, suspension clearance, exhaust clearance, etc.

I have to tell you, I have NEVER, EVERseen a pinion bearing go in a diff from running gears that were too high (numerically low), and I have tinkered with too many diffs to count. You are simply getting bad information on this one. If this were the case, Dana Corp would have to re-design each of their differentials with sequentially larger bearing sizes for each numerically lower ratio. As an example, you can get a Dana 44 from something like a 2.72 gear all the way to a 5.89. If what you are saying is true, the 2.72 would need huge pinion bearings as compared to the 5.89.


CRASH

 

[ashmanjeepxj]

There are two main issues and one ancillary issue with a D-30 that need to be addressed to run any tire larger than 33".

The first is the stiffness of the axle assembly. A D-30 with 37's is going to flex like a wet noodle torsionally and axially. This is not good for the life of any TAD, and is also hard on pinion shafts, as the ring gear tries to force itself into the pinion. Hence, Joachims tooth skipping incident. We have found that an OX locker is helpfull, but not a cure all, because of its extra beefy cover. It really seems to help hold things together.

Second issue is brakes. D-30 brakes suck ass, in case you haven't noticed. They are marginally safe with 33's, and not safe at all with 37's. There are numerous ways to adress this with WJ brake parts, but it's neither simple or cheap.

Third issue is gearing. 4.88 ratios in D-30's have been known to fail before 760 joints. Do you really want your weak link to be the ring and pinion? So if you want strong gears and want to run 37's, you are forced to run 4.56's, which is not near deep enough for highway or crawling use. They might be OK if you have a deep geared manual trans and an Atlas or Klune-V. As a comparison, I think 4.88's and 35's are about perfect, and i have an NV4500 with a 6.3 to 1 first and a 27% OD. I spin 2800 on the freeway in OD going just over 75.

In conclusion, by the time you get through building up your 30 to handle 37's you can have yourself a 44 that allows you to safely turn up to 5.38 gears, is a much larger, much stiffer assembly, has good brakes stock (spectacular with aftermarket, twin piston calipers), and the ability to easily run high steer.

Good luck!

CRASH

Dont forget steering?
The d30 has only afew steering solutions to lifts large enoguth to fit 37-38s...

the d44 flat top knuckles are a HUGE pluse when you need better steering..

 

[FlxnXJ]

I ran a XJ 30 with35" MTR's, and was acually pulling the tubes out of the housing! I also was running the smaller joints and broke one about every 3rd trip!

Now Iam running a full width HP 44 out of a 79 Bronco on 37: boggers, well I have been running it for about a year and have broke about 12 axle shafts! running 760 joints!

I just recently bought Warns and CTM's, for the 44 and they have been through hell and are still in great shape, hopefully my ring and pinnion will stay in good shape too

Bottom line if you wheel hard save ahead of time and get a 60, or if you are trying to build light, do a 9" with 60 outters.

 

[XJoachim]

HUH? Lockout hubs equal CTM no-turny....no-turny equal no wear. Jack from CTM has been running his CJ with the front hubs locked for 2+ years, the CTM spinning away every day, with no discernable wear on them at all. So I would say they would be just fine even with an OEM XJ 30, and they would likely outlast your lifetime in a rig with lockout hubs.

I said i don't know how the CTM's would behave in a daily driver, good to hear that they don't wear.

As for the pinion bearing let me tell you that the most work i do is on pinion bearing that are worn because of a numerical too low gering. The pinion also gets vertical forces when accelerating and this is what produces the wear on a D30 with an incorrect gearing. Then you will get a vibration from the front, the pinion will start to break teeth and finally the pinion will fail, not the bearing itself.

As i plan to go larger and maybe change to a coilover suspension in future i will swap out axles. The axles will be replaced by a front 60 and a rear 60 or 70.

 

[ashmanjeepxj]

The axles will be replaced by a front 60 and a rear 60 or 70.

Do the d70.

Even the front d60 Needs to be upgraded...
Mines a stock 79 and no its not mounted and hasent been wheeled yet, but the axle shafts have alot of neck down and the outers are tiny 30 spline stubs..

Here is the d60 shaft next to the d30 shaft, the Ujoint is HUGE but see how the factory pre 1980 shaft has neckdown...

35 splien outers, warn hubs, and no neck down shafts and CTMs can be swapped into the d60 front to make them work...

 

[XJoachim]

The 60 front comes out of a M 1009 (Chevy K 30 Pickup) Diff will be moved to the drivers side (pass. side diff) and has the 35 spline inner axles and 5-332 u-joints and manual locking hubs.

The 70 will be out of an Army airfield 2WD F 350. It's a 70 HD (duallie) with 7.17:1 gears and a detroit locker.

 

[csudman]

Bottom line if you wheel hard save ahead of time and get a 60, or if you are trying to build light, do a 9" with 60 outters. [/B]

Know of any writeups on this situation. I'm doing a 9" rear and can get others cheaply. I realize this is probably not a cheap option but sounds doable.

 

[TOZOVR]

My bud Tim Wheels the living jesus out of his LP 30...he has a new front end waiting to go in (built HP 30 with 760's etc...) and has yet to blow it up on his 36" SX's....he did manage to kill the 44 in the rear though....