Review: RCV Dana 30 Shafts

[SirFuego]

So a little over a year ago, I purchased a set of the 27 spline Ultimate CV Axle Set for a Dana 30 from RCV Performance as soon as they came out. These are chromolly shafts that utilize billet chromo CV joints instead of the traditional u-joint setup. I'm normally not one who buys something as soon as they come out, but they utilized the same CVs as their Rubicon 44 shafts (which is a smaller version of their Dana 60 shafts) just with a different spline count and I was in the market for chromo shafts since a catastrophic stock shaft failure that also took out my R&P and carrier. While I was really excited about the purchase, I told myself that I wasn't going to do any formal review of them until I got some trail miles on them.

Purchase
I actually ordered the shafts before the manufacturing details were ironed out. I heard there had been some test sets out there already, but they hadn't finalized the manufacturing, so I knew I was going to wait a couple weeks. They had some setbatcks in parts availability in that time, and I'll admit that I was probably labelled as a "tough" customer because I really, really wanted them for my trip to Big Dogs, but they did end up overnighting the shafts to me so I could get them in. In the end, I was happy with the customer service because I understand that they were not "finalized" for production, so I appreciated them doing everything they could to get me on the trails.

Now as for the price... This is probably the biggest disadvantage to these shafts as they are currently at $985/set last time I checked. These are definitely by far the most expensive chromo shaft for a D30 on the market, BUT they are cheaper than getting chomo shafts and CTMs -- and can be street driven without lockout hubs. For this reason, I will tell you that these shafts are not for everyone, but they are definitely worth it to a lot of people. Read on to see which group you fall in.

Installation
My Jeep was already in the shop for a R&P install, so I just had them shipped and installed there since they came the morning of the day I was going to leave. They provide detailed installation instructions, but they do also include the necessary hardware for the installation. Due to the size of the CV boot, you will need to grind out part of the hub bolt holes in the knuckle (they give you a metal template ring to check for proper clearances) and use the new hub bolts they provide you.

They were absolutely gorgeous outside of the axle:


And even more pretty installed:


Maintenance
This is one of the big advantages of the CVs in that the maintenance is very minimal. There are no u-joint caps to keep tabs on and no axle ears to worry about stretching. I live an in area where I need to drive through mud where ever I go and I've been buried in some deep mud -- and the boots do an excellent job at keeping the mud out. The boots are still in great condition after a year of wheeling. The CVs only require a shot or two of grease every 6 months or so. My shafts were greasable at the hub, but from my understanding the newer ones come with an axle seal you can use to grease the CVs with. I've recently had the shafts out and disassembled -- and they showed no signs of wear.

Warranty
At the time I purchased these axles, many of the other manufacturers I was considering had known backlogs in warranty requests. This was a big concern for me because I didn't want a huge turnaround time should I need to use the warranty. RCV makes all of their shafts in house (and at the time of purchase), so I didn't feel concerned about a backlog of getting the shafts made at a different facility. They offer a "you break it, we replace it" guarantee. I have heard good things about their warranty policy for the D60 shafts -- even when they technically shouldn't have been warranted due to improper setup.

I've also verified with RCV that the warranty is fully transferrable to any future owners.

Strength
So how do these shafts compare in strength to other chromo shafts? The shafts themselves are probably just as strong as other chromo shafts, but the CVs (at full steering lock) have been tested to be on par with stock Dana 60 u-joint strength (straight -- not steered). This was one of the big selling points to me as the CVs don't significantly lose strength as you steer -- unlike u-joints. I don't need to worry about breaking a shaft/joint when giving a healthy bump at full steering lock. While I haven't seen any chromo shaft fail, I have seen the u-joints fail -- which in turn take out the shaft ears (so I guess the shaft did fail, but it was a result of something else). These failures have all happened at (near) full steering lock.

We know that when u-joints fail, if not serviced right away, the ears can push off each other and take out a ball joint -- but what happens if a CV fails? Now I'm happy to report that I haven't had the pleasure of finding out, but their Dana 60 CVs (a bigger version of these CVs) have been broken before. In every instance I could find through my web wheeling, the inner race or cage of the joint failed, but the CV never separated -- which is a good thing since it won't take out a ball joint. This was also a big selling point for me because I know that everything breaks, so I felt that these would minimize any collateral damage should they fail.

I don't want anyone to think that these are the ONLY good option for a D30 or that staying with a traditional chromo/u-joint setup will guarantee you a catastrophic failure. Other brands of chromo shafts have been proven to work very well. I was looking at this problem from a "worst case" perspective and I came to the conclusion that the RCVs offer a better worst case scenario.

How They Perform
OK, so after reading through all of that, I've talked about a lot of stuff that doesn't matter when it comes down to it -- how do they work?

I can tell you that I couldn't be happier with these shafts and like I said they have shown no signs of wear, but I have broken my internals on my D30. The risk you take with any chromo shaft in a D30 is transferring the weak point to the R&P/carrier/crosspin. I had my front end bound up REALLY bad (pointing downhill trying to climb a 4 or 5 foot ledge) and I later found out that my crosspin had shattered into 3 pieces. It would then bang off of the pinion and chip away at it -- the force of when it bound up also took out the carrier. So I found a carrier locally, ordered a new R&P and found an upgraded crosspin from Richmond. I've been running this setup all year and don't have any complaints. This type of failure can happen with ANY chromo shaft setup, though. That said, I'm convinced that I would have went through a LOT more stock shafts in this same time period -- so what is down time on the trail worth to you?

I have noticed that my front end doesn't hop as much since installing these shafts. I'm not scared to give it a healthy bump at full steering lock, either. Many of my friends have been very, very impressed with the abuse I put my D30 through.

That said, these aren't one tons, so you can't just hit everything at full throttle and expect the front axle to hold up. IMO, this is a great upgrade for anyone looking to run 36s or less. I ran these with 36s for most of last year and have just changed to softer 35s with a LOT more tread. I know I will eventually upgrade to built 1 tons in the future, but due to other life expenses, it won't happen for some time -- so I think that these have been a great upgrade to my D30 that lets me still run the trails I want to with a bit more reassurance that I'm not going to be working on my axle every time I go out and wheel.

Like I said, with the price point, they aren't for everyone. However, they definitely work for me and feel as if it was the correct purchase given my own circumstances. Please don't hesitate to post up any comments or questions.

[ELLLLLIOTTTTT]

Nice writeup.

$1k would be well on the way to a front D44. But with marginal gains in strength without also having chromo 44 shafts, I can see how these would be a good option for people not wanting to dump even more money into a beefier front axle. Are you still running the stock unit bearings? Or selectable hubs?

[SirFuego]

Stock unit bearings. I do not know if they are compatible with selectable hubs.

Yeah, I agree that when you are talking $1k, a D44 should be taken into consideration, but that also isn't a "bolt on" application for those without fab skills. In addition, you would still be running the same 760x u-joints short of investing the money in chromos like you said.

FWIW, they have also released a D44 version that is compatible with traditional non-unit bearing hubs. I cannot comment on those either, but they might also be an option for anyone running a Ford or Waggy 44.

[zjeepin]

nice writeup jared, we don't have many writeup guys on here anymore..

I had a set of 33 spline chromos and longfield joints in my d44 that cost me the same as your d30 setup plus another 7 or 800 in building the 44 with a locker, gears, bearings blah blah blah.. i could have afforded a 60 alot sooner if i'd held onto the extra 800 i put into the 44 but the rcv's weren't available at that time.

you've got some sound reasoning there..

[JordanA]

Hm... It looks like they've got 30 spline CV's for the old D44's. I may have to look into these during my rebuild for my Scout II.

[AgitatedPancake]

That they do, released D44 shafts for original style spindles last year! They also do custom anything for you, spline counts, lengths, etc.

Good to hear they held up so well for ya man! As far as I've seen RCV seems to be the end-all solution in any market they cover

[ATL ZJ]

Jared are the 30 inners and outers both just high quality 4340 or are the bells, stubs, and stars 300m like the 60 shafts? I've been curious whether the price difference between the smaller shafts and the 60 stuff is due to the type of materials used or the amount of materials used. any idea?

[SirFuego]

From RCV's website regarding the materials in the D30 shafts:
"Billet chromoly CV joints replace the old school u-joints combined with chromoly inner axles deliver more power to he ground"

I can tell you that the D60 CVs are significantly larger than the D30 ones. My buddy is running them in his HP60. I can't answer your question though as to whether the materials are the same. It's possible that they deemed 300m unnecessary for a D30 application so they were able to cut costs. I'm going to guess, though, that pricing is moreso based on supply/demand and competitors pricing.

Another thing to consider is that all of the D30 axles they make are identical, so production costs are probably less. They do offer custom sizes, but they do also charge more for the custom cut (some WJ guys have contacted them regarding making them to WJ length and they were quoted like $1200-1300 IIRC).

ALL D60 shafts they make are custom -- and you need to give them a set of measurements to properly cut the axles. I'm guessing this is also another reason for them costing about twice as much.

[SirFuego]

Was just playing around on Poly Performance's website.

Looks like WJ owners have another option for chromo shafts. Considering the only other chromo WJ shafts I've seen are $800+shipping with Spicer u-joints, price isn't horribly outrageous.
http://www.polyperformance.com/shop/...J-p-26769.html

[Jeeptech01]

Hey Fuego how often were you killing unit bearings on the 36's? Id hate to drop coin on rcv's only to have unit bearings on a revolving door system.

[Kauzi Zj]

Hey Fuego how often were you killing unit bearings on the 36's? Id hate to drop coin on rcv's only to have unit bearings on a revolving door system.

This +

Since this is something I am considering, I will be buying new R&P, anything else I would need to do to beef up my 30? As you know the vast majority of my "wheeling" is Moab style crawling, the trail stuff is dirt roads, I will RARELY, (like 1 out of a 1000 trips) ever be in the type of situations you face full throttle through mud to get up an obstacle.

It seems as though the RCV shafts would be the perfect setup for me?

[SirFuego]

My unit bearings were replaced a few years ago when the hp30 went in on 33s. Haven't had to replace them since...

[SirFuego]

Maybe I'm lucky but I just don't see why unit bearings suck so badly. I understand they aren't cheap but I guess I'm jaded since they haven't been an issue for me. Perhaps I didn't run into issues because it never saw street time on 36s? I dunno.

Edit: I also speculate that cvs may be easier on the unit bearings than ujoints. Ujoints dont turn at a constant speed so those small changes may be harder on the unit bearings. I don't know if there is any truth to that or not but its something that has crossed my mind...

I also suspect these minimize any chance of knuckle or ball joint failure since the shafts wont push off of each other if they do break...

Kauzi - I suspect they would be good for you. I would recommend these to anyone expecting their hp30 to be their last axle for a while. With the warranty being fully trasferrable they should hold resale really well.

[cowboy63b]

My unit bearings were replaced a few years ago when the hp30 went in on 33s. Haven't had to replace them since...

Who did you go with on your unit bearings? And who did you get em from?

[Jeeptech01]

I think you may be onto something with the cv's saving the unit bearings. Since the u jointed shafts will push and pull at the bearing with each revolution it may fatigue the bearing much more rapidly. I never killed any hub bearings in my WJ with the OE cv axles but then again I was only on 32's.

It would be interesting to see the lifespan of the unit bearing if someone left the factory cv's in their zj vs swapping in a set of XJ shafts. Problem is the mortality rate of factory cv axles.

[IndyZJ]

It would be interesting to see the lifespan of the unit bearing if someone left the factory cv's in their zj vs swapping in a set of XJ shafts. Problem is the mortality rate of factory cv axles.

~165k total miles with 30k of those being on 31s with factory backspacing, the rest of the time completely stock.

Fuego, did your rig see much street time or many miles in general with that setup? If not, that may be why they lasted for a long period of time. I would imagine that turning with any kind of speed on the street is harder on bearings than sidehilling.

[SirFuego]

It saw 3k street miles on 33s and none on 36s. So take that for What its worth in terms of longevity of my timken bearings. They actually came from the previous owner of the axle so I don't know how much mileage was on them to be honest.

[BigDaveZJ]

The last unit bearing I recall replacing was back in like 02 or 03. That's only like 20k in mileage but certainly not an easy 20k. And I'm running stock TJ shafts. I carry 3 spares on the trail with me though, 2 already attached to shafts and one loose.

[Root Moose]

FWIW, I got ~160k miles out of the uni-bearings on my "street Jeep". The only off-road it ever saw was mud on mild logging roads.

I'm intrigued by these RCV shafts. Have you noticed if the road noise levels are any less with them? In theory they should be quieter - just curious if it is noticeable in the real world. Maybe you can't tell given how your Jeep is set up?

[SirFuego]

Haha. I can't hear anything and there are vibrations everywhere. So I can't tell anything.

[Crasher]

This is an old post, but I have a question. I have the RCVs in my JKU Rubi and they are very smooth under tight turns while crawling. I like them well enough, that I am considering them for the HP 30 in my 97 ZJ. If you mentioned a locker, I missed it, but I have an OXlocker and 488s in the HP30 and stock shafts with 33s. I'm going to 34" MTRs or 35" KM2s and want a little more shaft reliability. (haven't broken any yet) Will this combo with RCV shafts be too much for the 488 gearset? Or, should I just run the stocks and continue to carry spares. As with our JK, the RCVs are overkill for our style, but we're retired and do not want a broken axle on the trail.

[SirFuego]

I ran an Aussie locker in mine, so I was still running the stock carrier (which was my weak point with 4.10s) I would bet money that the Ox is a lot stronger than the stock carrier, so you would be good there.

I never ran any deeper than 4.10s, so I don't have any first hand experience with them -- but honestly the stories I've heard about 4.88 ring gears breaking was one of the major reasons I stuck with 4.10s. One other thing to consider is that the metal pieces from a broken R&P can also damage other stuff in the housing.

I have a pretty aggressive driving style, but the only time I ever had problem was in shock load situations -- which I tried to avoid, but wasn't always successful in doing so.

The way I looked at it was that I would probably have broken X shafts/joints before I ever broke anything internally -- so while the breakage was basically weekend ending, I had very little downtime on the trails due to axle problems. FWIW, I averaged one carrier/R&P a year.

[SquirrelPig]

Great info and thread guys. I've got an HP30 with 4.56s and a Lock-Rite I haven't installed in my ZJ yet. I'm only running 33's for now, but I wonder about the longevity of the shafts if/when I upgrade to 35's or bigger. I've looked at RCV, and bang for the buck they seem like the way to go.

[Crasher]

QUOTE: (I never ran any deeper than 4.10s, so I don't have any first hand experience with them -- but honestly the stories I've heard about 4.88 ring gears breaking was one of the major reasons I stuck with 4.10s. One other thing to consider is that the metal pieces from a broken R&P can also damage other stuff in the housing.)

I too, have been concerned about the 488s and have been carefull to avoid shock situations. So far, so good. However, when I go to 35s, there is likely to be more load on everything. I also use the ZJ as a fill in DD sometimes and with the weight of everything I have added, ( F&R bumpers w/winch and tire carrier, Claytons long arms, etc.)plus 35s, it needs the 488s to be decent on the road. I've thought about going to a 4:1 tc or a deeper atlas and regearing back to 4.10s for a bigger R&P, but then it would be a dog on the road.

My type of offroading, slow rock crawling, generally is a matter of picking a good line and keeping all 4 wheels on the ground. I'll never be in mud or snow. With that and an easy skinny pedal, I should be ok. From what I've read here and my experience with RCVs in my JKU, I think I will get a set. The next decision is whether to continue with the lockrite in the 8.8 or replace it with a Detroit. This build process never ends.

As a side note, all ZJ owners will love this. After a few months of offroading with our built 2010 JKU Rubicon, my wife prefers the ZJ, which is why I'm improving it. Next winter, the Rubi will sit in the garage in WI while we rock crawl with the ZJ in AZ. Go figure!!!