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Opinions please. Front D30 issue.

Fozzy_Bear

NAXJA Forum User
Location
Norfolk, Va
Ok, so, here's the story:

I have 250,000 miles on a D30 front axle in my jeep. I had a "clunk" that I thought was something else, but turned out to be caused from one of the caps on the Pass' side U joint falling completely off and the trunion banging around in the hole.

So, I figure: "No problem, one new U-joint coming right up.". But then I start wondering how much dammage was done to the mounting surface while the clunking was going on. (It was like that when I bought it a few months ago.)

So then I was thinking about replacing THAT too. And I start noticing that people who upgrade their front axle often sell the entire front D30 assembly (stearing and all) for next to free since nobody ever seems to WANT a D30 front end.

So here is my question for any who care to converse. If it were your rig, would you :

1) Replace the U joint and run it 'til it blows up - replacing the whole axel at that point.

2) Replace the U and associated components and start saving for a front D44 later this year.

3) replace the entire front end with a lower milage D30, taking the oppurtunity to put a locker in it while it is "on the bench"

4) Run it with the clunk until I have enough to get a better front end.

5) Other cool sounding idea that I haven't mentioned


please note:
Yes, I will be receptive to posts mentioning any front axel you may be looking to sell.


For a bit of context, here is my current plan for this rig:
I expect that within the next 8 months this '89 XJ will have 2- 4 inches of lift with either 31's or 33's (depending on the lift being either 2 or 4). I am going to put very low gears in it ( 4.88 ) with the intention of having a truck that sits around all week and then is a weekend toy. I still want it street legal, so I can use it to haul stuff to the dump, and get me to work in foul weather (it floods often where I live and my Daily Driver is low to the ground)


So what would you do?
 
OK here are some thoughts:
Are you really sure the sound is in the axle? could it be suspension? steering? anything else? It could also be the unibearing.

ANyways if it turns out to be a part of an axle, then if you replace it the noise goes away (provided that the one that you swap in didn't have a new and different noise ;) ). My suggestion would be to try and isolate the noise and deal with it while keeping an eye out for a spare housing that you can work on for the future regear/locker project (there are some things that you can reinforce on the D30 making it a much nicer axle).
 
Most likely all you need is a new front u-joint, and the other side is on its way out also. The D30 can take alot of abuse, so don't write it off just yet.
 
You don't mention year, but with 250K I'll take a guess that it's old, and has the CAD system.
I'd swap in new axleshafts with the stronger 297x u-joints, and also get rid if the vacuum system at the same time. Then you should be good for 31's on the d30 without many problems. Looks for suitable axle shafts from a newer D30 from an XJ, I believe that you can also use TJ shafts, and maybe even shafts from a Grand. Look into it, then you'll get new yokes, upgraded u joints and get rid of the vacuum disconnect that is sometimes(!) problematic.
 
87manche said:
You don't mention year, but with 250K I'll take a guess that it's old, ...

It was tucked away down at the bottom of the post. It's an '89 and yes, it has the vaccume disconnect.

87manche said:
...
I believe that you can also use TJ shafts, and maybe even shafts from a Grand. Look into it, then you'll get new yokes, upgraded u joints and get rid of the vacuum disconnect that is sometimes(!) problematic.

I was planning on getting the cable replacement actuator, IF I keep the axle. But that is just one more reason I am willing to consider swapping axles. So now... I'm replacing the U-joint, swapping shafts OR replacing the actuator, buying new yokes, regearing, adding a locker... etc. Then I still have a D30 with parts of it seeing a quarter-million miles go by. At some point I have to start wondering if I am just wasting my time/money when I should have just scrapped the stocker from the get-go.

Granted, I AM aware that with my plans for this jeep, a D30 should indeed be quite fine. If I was planning on going to 35's, this whole issue would be a no-brainer.

Kejtar said:
OK here are some thoughts:
Are you really sure the sound is in the axle? could it be suspension? steering? anything else? It could also be the unibearing.
...

I'm pretty sure. I was watching when a friend slowly pulled it forward and I watched it go "clunk". But, to be totally honest, that doesn't actually mean it's the ONLY clunk in the front end I have. This IS a high milage truck we are talking about.
 
I'd throw some new, non disconnect shafts in with 760 u-joints and run it. The dana 30 will hold up to an amazing amount of abuse for what it is, and unless you plan on going 35/37" tires, there is no reason for you to go to a 44. Putting a 44 in can be an amazing amount of work if you don't have alot of fab experiance, and won't clear well without a good bit of lift.. not to mention, it can be very expensive to do well.
 
D30's like 297's, trussing, and aftermarket axle seals to replace the
plastic "mudslingers" on the shafts.
Have fun with it.
 
Thanks for all of the info guys.

I just want to avoid being nickle-and-dimed to the point where I look back and see that I have spend more money patching the stock piece than I would have spent replacing it with something stronger.

I'm feeling better about putting some money into what I have already got. Both because of feeling better about he D30 and from feeling worse about upgrading to something else. - Kinda' makes it easy.

So while I have your attention,
87manche said:
...
I'd swap in new axleshafts with the stronger 297x u-joints,
...
cal said:
I'd throw some new, non disconnect shafts in with 760 u-joints and run it. ...

What do those indentification numbers mean. And is there a consensus on why I would choose one over the other? Or is it just personal preference?


Lodi Jim said:
D30's like 297's, trussing, and aftermarket axle seals to replace the plastic "mudslingers" on the shafts.
Have fun with it.

Are there any aftermarket seals that are beeter than the rest? Or is the only thing that matters that they are not the factory pieces?

Where would be the best place to buy them?
 
87manche said:
You don't mention year, but with 250K I'll take a guess that it's old, and has the CAD system.
I'd swap in new axleshafts with the stronger 297x u-joints, and also get rid if the vacuum system at the same time. Then you should be good for 31's on the d30 without many problems. Looks for suitable axle shafts from a newer D30 from an XJ, I believe that you can also use TJ shafts, and maybe even shafts from a Grand. Look into it, then you'll get new yokes, upgraded u joints and get rid of the vacuum disconnect that is sometimes(!) problematic.
Yeah until you figure out the problems. I fixed all mine. New steel shift fork. Fresh lines to the vacuum motor. The size of the disco axles are huge. The biggest problem is the fork. Replace it with steel. Spicer sells one for $15. Then if your locked and not in 4 wheel drive you can not even tell there is a locker in there. I'd personally keep the disco. I think I'd rather break the collar too before an axle. So like everything else there are always 2 stories to each tell. JMO !
 
boise49ers said:
...
always 2 stories to each tell. JMO !
[/I]

Thanks for the input. I _DID_ ask for opinions.

As for the axle, it has become a non-issue. While i was looking for a rear axle to replace my D35 out back, I came across a guy selling a set of axles (D44 back and a '96 D30 front) with matching 4.88 gears and a locker already installed. He had even set the pinion angle to the same lift I was planning. So I went ahead and bought the set.

I'll have a new '96 front D30 on my rig (hopefully) next weekend.
 
the other option is to go with shafts from a 95 YJ, that's my plan for my front d30. That way you get the upgraded 297 u joints and get to keep the CAD.
 
langer1 said:
4.88 you own your own gas station?
what are you implying?
 
langer1 said:
4.88 you own your own gas station?

:)

No, but I don't drive the jeep every day either. My daily-driver gets 22/28 mpg. I don't honestly care what my jeep gets. It is either hauling junk to the dump, or on it's way to a trail. The only problem will come from the long distance trail rides, and I'll just budget a full tank of gas as part of the cost of the run.

I mentioned that in the original post, but it was burried toward the bottom.
 
Fozzy_Bear said:
:) I mentioned that in the original post, but it was burried toward the bottom.
Yep you did, throw 37s on there and your running about factory any way.:confused1
I wish I had 4:88s. I'm swapping my 35 out for a 44 soon. I just don't want to have to regear
again. So I'm having a detroit and 4.56s put in that one too. I'm running 34s so I'm actually
right on for factory gear ratio. Of course the factory didn't count on us crawling up Rocks either.
Yes I'm kidding about the 37s on an XJ. Gotta have a chop job to do that.
 
Last edited:
boise49ers said:
...
and your running about factory any way ... Of course the factory didn't count on us crawling up Rocks either.
...

Exactly.
I don't need to stay near the factory ratio (since I have a car to drive on the street). Now, I WILL want an accurate speedometer for getting to and from the trail, but other than that, I'll take the lowest gears I can get. Heck, after I put on the mods that I currently have ordered, the only thing left on my wish-list is a second NP231 configured as a doubler. (until I tear something up... :repair: )
I have pretty much chosen to go with 32 inch tires. So with a 4.88 that should put me in the far end of "reasonable" on the graphs that are floating around the internet. And the far end of reasonable is just what I'm looking for (right now)
The way I figure it, putting lower gears in the diff's is a heck of a lot cheaper than what I would have to do to the engine to get an equivalant amount of torque. And if I am also limiting the top end speed of my rig; well, the thing is a brick that would never get past 80mph anyway.

On the topic of graphs ... does anybody out there have a bookmark for any of the speedo-gear charts handy? I know there out there if I search. I'm just wondering if anybody knows one off the top of their head.

thanks
 
GoJeep has one on his website. Look up his user name and there will be a link.
I have a ratio chart on this page. You will be running on the high end of power. Lots of torque, but if it is like I was with 31s and 4.56s, I really didn't like it at all. You shift into high gear way to soon. It rips through all 4 real fast. You'll be wanting that over drive just to make it bearable.But you say it is mostly a trail rig you should be OK. With 32s. I don't know why you would need to try and make a 4.1 TC. Sure if you are gonna jump to a bigger tire at some point, but the clearance allowed with a 32 tire you won't need that low of a crawl ratio. JMO ! Have fun
http://myweb.cableone.net/cherokeexj/Upgrades.html:sunshine:
 
boise49ers said:
GoJeep has one on his website. Look up his user name and there will be a link.
...
I don't know why you would need to try and make a 4.1 TC.
...
http://myweb.cableone.net/cherokeexj/Upgrades.html:sunshine:

thanks for the links.

As for the doubler TC; I know I will not NEED it. It is really just to cover my butt. Ya see... I have a manual tanny and I have ZERO experience rock crawling (living where I do, we have mud or sand as far as the eye can see, but no rocks within a 3 hours drive. Even a slight hill is 90 minutes away). And, my brother is always trying to get me to go crawling with him (near HIS house. a few hours west of here). Quite frankly, if I embarrass myself by constantly stalling the rig on the rocks, I am betting that multiplying my crawl ratio by another 2.7 (or possibly 4.0) would help out without "givving up" and swapping in an auto.

So while I would like to think that I'll be OK, I'm not going to assume that I am a natural-born crawler able to handle anything. Heck, I barely drive the jeep, so I don't get that much practice with the clutch at all. If I remember correctly, the 5 speed has a first gear of right about 3:1. That puts my new crawl ratio at 3*2.7*4.88 or, right under 40. If I add even a stock NP231, that goes to over 106. (or over 150 if I use a 231 with the tera-low 4.0 kit) I'm betting that even a auto-driving-city-boy-rock-n00b like me can get by with a 100+ crawl ratio. (If not, then I really DO need to pack it in and buy an auto :sad1: )

.
 
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