anyone running 36 or 37's on the d30

hey, im planning on getting 36" tsls or 37" mtr's and i wanted to know how the 30 is holding up and how often you bust u joints or other stuff. i have a lock-rite and 4.88 gears in it.

thanks Brian

do you have abs? aka 297 ujoints?

if you dont, DONT DO IT

297s will barely survive on that tire choice, let alone 260s!

ps, if you wheel it hard, youre screwed, just get a 44

I'm only on 35s but i wheel with acouple of guys on both 36 tsls and 37 claws. Your main thing would be to upgrade to alloyshafts and atleast 760 joints if not ctms. Another issue is tha some lunch box lockers give out along with the stock carrier uder that much stress.

I hung out with a YJ on 38s on a D30, but it had the warn setup.

I am running a HP D30 with a Lockright, 760 joints, stock inners and outers on 37" MTRs. Just got back from Moab and didn't break anything. I have broken a 297 joint, inner and outer shafts with 35" MTRs but I was being mean to it.
If you have a light right foot you should be ok for a while. I carry spare shafts with me on the trail.

hjeepxj said:

do you have abs? aka 297 ujoints?

if you dont, DONT DO IT

297s will barely survive on that tire choice, let alone 260s!

ps, if you wheel it hard, youre screwed, just get a 44

Click to expand...

What in your opinion is the difference between a D30 with 297 u-joints and a D44?

I run 38.5 TSL SX on a D30 with a detroit locker and only managed to break a u-joint with the lockright locker skipping teeth. Due to these shock loads i broke one.

Get WARN alloy inner axles or the superior chromoly axles, grind the shafts to accept real snap rings instead of these whimpy clips and they will hold up if you're not doing stupid things.

Remémber, you can break anything if you try hard enough.

Like pair8hd pointed out, use the 5-760x u-joints, they have no greese zerk and are stronger. You may have to replace them regularly because there is no zerk, but they hold up better.

Oh yeah, another thing, the lockright was replaced with a detroit due to skipping teeth. It didn't manage to turn the 38.5s under load. If you want a locker in front get a detroit or a similar locker that replaces the carrier.

i'm running 36's on my D30, but i haven't truly 'gott'n it' with them yet as I've still be doing other work on the rig. I've been trying to go easy on it. So far no broken stuff, but not many trail rides either. I only run 33's on the street.

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

XJoachim said:

What in your opinion is the difference between a D30 with 297 u-joints and a D44?

I run 38.5 TSL SX on a D30 with a detroit locker and only managed to break a u-joint with the lockright locker skipping teeth. Due to these shock loads i broke one.

Get WARN alloy inner axles or the superior chromoly axles, grind the shafts to accept real snap rings instead of these whimpy clips and they will hold up if you're not doing stupid things.

Remémber, you can break anything if you try hard enough.

Click to expand...

the 297 ujoints of the 44 are the same as the dana 30 ones...but the shafts, r&p, carrier, housing, theyre all stronger in a dana 44, in a dana 30, there is always a weak link, when your running 35+ tires...

i really am suprised that youve only broke a ujoint in your dana 30 with 38.5's, you germans mustnt have a heavy foot when it comes to wheelin

I managed to break a center bolt in the D30 carrier so don't tell me we're not wheelin' hard.

We don't have rock so no rockcrawling, but going through deep mud with a lot of obstacles in it and then going uphill muddy and steep 50 feet with spinnin' wheels is hard.

Sometimes i see videos of guys almost burning their tyres with a screaming V-8 and i just count the seconds where something starts to break. Maybe we are a bit easier with the right foot, we call it "smart driving". We don't have those big junkyards where we can pull parts for cheap so we have to be a bit more careful.

A 60 front and 70 rear is in the plans but i want to see how far i can go with the stock axles before i go extreme. So far i can say that the D30 holds up well with the WARN inner axles (which are stronger than D44 stock axles) stock outers (same as D44) and a detroit.

As i wrote in my post you have to modify the axles a bit to fit real snap rings instead of the clips that hold the caps. The most common reason for u-joint failure is failure of this clip, the cap gets out and gets cracked and at this moment the u-joint breaks because the load doesn't split evenly. If you do a bit research and do a little math you will find out that you cannot produce enough torque with the stock I-6 and stock axles to break a 5-760x u-joint under normal load. You have to produce a shock load to break one of these things and this is exactly what happened when i broke this one u-joint. The lockright skipped teeth and under full throttle the over 18 month old u-joint gave up because of the generated shock loads.

Sorry for this long post.:anon:

Your math equation apparently does not take into account Atlas t-cases and a 760 joint operating near the edges of it's angular limits.

CRASH

I may run some 37s for a season, before i get a 44 built up. I plan on taking it easy on the throttle and having spare shaft and hub assemblys. I fully expect the brakes to be bad, the gearing is going to really suck on road, and be marginal off road (4.10s and 4-1 kit in the t-case). I may run a simple truss from the pig to the vac disco mount, and small trusses to the coil mounts on each side. I also run a full carrier selectable locker.

Next winters project will be a HP 44 with 5.38s, ARB and high steer.

CRASH said:

Your math equation apparently does not take into account Atlas t-cases and a 760 joint operating near the edges of it's angular limits.

CRASH

Click to expand...

As i said before the math is done on a stock drivetrain with 4.56:1 gears. No Atlas or Klune-V or 4:1 t-case calculated.

But if you have an Atlas and maybe a stroked engine and lower gears your only choice is a D60 with 5-332x u-joints because the u-joints of a D44 are the same as in the D30 and are going to break.

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

I'm wearing out ujoints, not breaking them
however my pinion is chunked

this is a year of trails, a very small amount of city driving, about 500 miles in the last year.

still not sure where i'm going with a front axle

mac 'run whatcha brung' gyvr

4.10 is too low and puts too much stress on the pinion bearings because you have to push harder than anyone with lower gears.

4.10 is too low and puts too much stress on the pinion bearings because you have to push harder than anyone with lower gears.

Click to expand...

OK, Herr Joaquim, you're going to have to show me some math to back up this statement.......you are WAY out in left field here.

4.10 gears are much stronger than 4.88's, and given equal final drive ratios, produce the same load on U-joints and axleshafts. In fact, given equal torque multiplication in front of the axle, the 4.10's will stall the engine before the 4.88's will, thereby preventing parts failure.

CRASH

First you said this:

If you do a bit research and do a little math you will find out that you cannot produce enough torque with the stock I-6 and stock axles to break a 5-760x u-joint under normal load.

Click to expand...

You said stock axles, not stock drivetrain. There is a difference.

As i said before the math is done on a stock drivetrain with 4.56:1 gears. No Atlas or Klune-V or 4:1 t-case calculated.

Click to expand...

One of the joys of a Dana 44 is the ability to run hardened 30 spline axles and CTM joints. 30 spline axles are what come stock in OEM Dana 60 stubs. Nobody I know of is breaking 30 spline Warn shafts unless they bind them up with CTMs. Some have twisted Warn splines after breaking a standard 760 and binding the shafts up against the knuckles, but that is it.

My whole point here is that there are very definite and tangible advantages to running a Dana 44.

CRASH

Agreed, i may be not very clear on my "stock" declaration, also agree that you can beef up a D44 to hold axles as strong as a D60 but they still have the 297/760 u-joint size. 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.

The higher the gering you have to push the right pedal more than anyone running lower gears to have the same effect i.e. when accelerating from a stop. The pinion bearings on a D30 will not hold up and will wear out quicker than with a lower gearing. Everybody can tell you that i'm correct on this. The higher the gearing the more stress you put on the pinion/driveshaft/t-case, the lower the gearing the stress goes to the ring gear/carrier/axle shaft/u-joint. The pinion bearings will just wear out quick, they will fail after worn out by jumping teeth.

4.88 is without doubt no choice for a well running I-6, it will hold up against a 4-banger but cannot withstand the I-6. 4.56 is the lowest i would go with D30.

I would say if you really run that hardcore stuff to buy hardened 30 spline axles and run CTMs in your D44 you better build a D60.