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View Full Version : How strong are the D30 CV axle joints?



robselina
09-25-2004, 11:56 AM
just curious if these things can take a beating or not. I'm not sure if you guys are swaping to u-joint axles or running them still.

I blew my front driveshaft on kane creek in moab on thursday, couldn't get the fawker fixed like I wanted and it ruined my weekend. Anyway, want to make sure that when I replace it, I'm not just going to start blowing axle CV joints.....

Jim311
09-25-2004, 12:21 PM
Ha.. I'll let you know when my front shaft from Tom Woods comes in Monday ;)



I've heard Kevin say that the CVs are pretty strong... but I can't confirm nor deny that. Ihaven't had any problems with mine, but I'm running open in the front anyway.

Krash80
09-25-2004, 04:39 PM
Moved to "chit chat"; this is not ADVANCED drivetrain tech.

FWIW...the CV's are great to run if you have spares and all your shafts have lifetime warranty at pep-boys or autozone. I ran CV's on my d30's with 33's and 4.56's for quite a while, and while i blew more than a few shafts, they were all replaced for free. I only broke them when i was trying an obstacle that i KNEW i'd break something on. So they work well for moderate wheeling, but when you start punishing them real hard they'll break...i'd equate them to about a 260 u-jointed shaft...possibly even a bit stronger from my experience.

-Ron-

robselina
09-25-2004, 05:14 PM
cool, that answers it. I'd like to run 33s and a lunchbox locker up front and not have to worry about it. Given my driving style, that sounds pretty realistic....


...now to go find a used XJ front driveshaft.....

OverkillZJ
09-28-2004, 02:03 AM
Moved to "chit chat"; this is not ADVANCED drivetrain tech.

FWIW...the CV's are great to run if you have spares and all your shafts have lifetime warranty at pep-boys or autozone. I ran CV's on my d30's with 33's and 4.56's for quite a while, and while i blew more than a few shafts, they were all replaced for free. I only broke them when i was trying an obstacle that i KNEW i'd break something on. So they work well for moderate wheeling, but when you start punishing them real hard they'll break...i'd equate them to about a 260 u-jointed shaft...possibly even a bit stronger from my experience.

-Ron-

Ya, Ron... About your shafts... I blew both of them up first time out last month.... :roll:

Ya, I punished them.

AnotherZJ
10-10-2004, 09:33 PM
I swapped out my CV fronts for U-jointed 5-760 shafts. Gotta tell you, I'm having enough enoying binding issues that I'm probably going to swap back to the CV shafts and keep the U-jointed ones as spares.

...anyone else reading this do this swap and have binding issues?

robselina
10-10-2004, 09:42 PM
weird. Must have something wrong there 'cause I've never heard of any binding issues. If you don't solve them though, i'll take those 760x shafts off your hands!

Nate Cannon
10-11-2004, 04:59 PM
with a locker in the front the CV's are in grave danger. It was the only thing I ever broke when I still had open diffs. When I was locked I broke a few, I think 6 total.
-Nate

robselina
10-12-2004, 10:33 AM
answered my own question :x

10 hours after I got my new driveshaft in, I went out for a night run at our local playground and blew the driver's side CV......

That's with 32x11.50s and an open diff BTW.....

Nordic1
10-12-2004, 10:47 AM
I never ever blew my CV driveshaft till maybe 50 feet out of the garage when I installed my 8" springs. That d-shaft had taken a beating for many years and simple angles is what took it out. In the HP30 I'm building, I will be getting u-jointed shafts however for the time being, in the last year or so I have only broken 1 CV axleshaft (and it was because I was being stupid). If you're not a madman on the throttle, for the short term, CV shafts will work fine.

robselina
10-12-2004, 12:21 PM
I never ever blew my CV driveshaft till maybe 50 feet out of the garage when I installed my 8" springs. That d-shaft had taken a beating for many years and simple angles is what took it out. In the HP30 I'm building, I will be getting u-jointed shafts however for the time being, in the last year or so I have only broken 1 CV axleshaft (and it was because I was being stupid). If you're not a madman on the throttle, for the short term, CV shafts will work fine.

My CV driveshaft blew under low load and only 3" of lift. I wasn't impressed. I'm happy with the new 1310 u-joint driveshaft though. The CV joint I blew last night was while trying to bump up a ledge. We'd had rain that day, so the rocks were really slick. I had to hit it a little harder than I liked, but it should have taken it, I wasn't being that rough....

Jim311
10-12-2004, 01:18 PM
I never ever blew my CV driveshaft till maybe 50 feet out of the garage when I installed my 8" springs. That d-shaft had taken a beating for many years and simple angles is what took it out. In the HP30 I'm building, I will be getting u-jointed shafts however for the time being, in the last year or so I have only broken 1 CV axleshaft (and it was because I was being stupid). If you're not a madman on the throttle, for the short term, CV shafts will work fine.

My CV driveshaft blew under low load and only 3" of lift. I wasn't impressed. I'm happy with the new 1310 u-joint driveshaft though. The CV joint I blew last night was while trying to bump up a ledge. We'd had rain that day, so the rocks were really slick. I had to hit it a little harder than I liked, but it should have taken it, I wasn't being that rough....


That's EXACTLY how my failed.

Nordic1
10-12-2004, 01:35 PM
I never ever blew my CV driveshaft till maybe 50 feet out of the garage when I installed my 8" springs. That d-shaft had taken a beating for many years and simple angles is what took it out. In the HP30 I'm building, I will be getting u-jointed shafts however for the time being, in the last year or so I have only broken 1 CV axleshaft (and it was because I was being stupid). If you're not a madman on the throttle, for the short term, CV shafts will work fine.

My CV driveshaft blew under low load and only 3" of lift. I wasn't impressed. I'm happy with the new 1310 u-joint driveshaft though. The CV joint I blew last night was while trying to bump up a ledge. We'd had rain that day, so the rocks were really slick. I had to hit it a little harder than I liked, but it should have taken it, I wasn't being that rough....

Thats how I broke mine as well :lol:

AnotherZJ
10-12-2004, 11:07 PM
weird. Must have something wrong there 'cause I've never heard of any binding issues. If you don't solve them though, i'll take those 760x shafts off your hands!]

I don't understand it either.. I know I could just adjust the steering stops, I'm just anal about giving up that much turning radius. Maybe it is just the bigger 760x joints that are the problem. The joint is definitely the binding point.

robselina
10-13-2004, 10:52 AM
weird. Must have something wrong there 'cause I've never heard of any binding issues. If you don't solve them though, i'll take those 760x shafts off your hands!]

I don't understand it either.. I know I could just adjust the steering stops, I'm just anal about giving up that much turning radius. Maybe it is just the bigger 760x joints that are the problem. The joint is definitely the binding point.

I've got a 3/4 ton D44 on my waggy, and of course it has 760s...I've got a pretty wicked turning radius and no problems with binding :?:

Trancezj
10-13-2004, 11:20 AM
People with binding problems... maybe have a 249 still?

AnotherZJ
10-14-2004, 12:49 PM
People with binding problems... maybe have a 249 still?

Yah...

..I know, I know....

gearhead313
10-14-2004, 03:01 PM
I break cv shafts going to the mall




that would be the first thing i'd recommend people to do....they will leave you stranded!!!

robselina
10-14-2004, 05:58 PM
....they will leave you stranded!!!

carry a 13mm 12 point socket and a jack and you won't have that problem :lol:

Jim311
10-14-2004, 09:10 PM
13MM? I thought the hub bolts were 1/2"


:shock:



I used 1/2 to get mine off anyway :o

LouisianaZJ
10-14-2004, 10:46 PM
13mm 12pt is correct

gearhead313
10-18-2004, 02:23 PM
....they will leave you stranded!!!

carry a 13mm 12 point socket and a jack and you won't have that problem :lol:


you forgot the actual shaft! my first time breaking it i didn't have one, and that suxord long time

grandman
10-18-2004, 09:08 PM
I broke my Det ez locke , it was locked like a mini spool , you could snap a cv by turning around in a parking lot honestly .

By the way , hello every one . I didnt see a new person area to introduce my self

MaineZJ
10-18-2004, 09:33 PM
People with binding problems... maybe have a 249 still?

Yah...

..I know, I know....

ever drive something with a part-time xfer case on pavement... that's what you're doing, that's why it's binding- not the axles fault

Kraqa
10-18-2004, 10:02 PM
i broke 3 CV joints in my front axle one with 31's and two with 33's. switched to u-joints and no probs.

robselina
10-19-2004, 10:56 AM
BTW - I've ordered 760x axle assemblies from my local crack dealer....They were cheaper than the NAPA replacement CV shafts! [D'OH!]

AnotherZJ
10-20-2004, 12:46 PM
People with binding problems... maybe have a 249 still?

Yah...

..I know, I know....

ever drive something with a part-time xfer case on pavement... that's what you're doing, that's why it's binding- not the axles fault

I had done some searching, and saw where some people with 249's had binding issues and some did not. A 231 swap is on my to do list.

Could you enlighten my newbie ass on why U-joints with a 249 bind, but CV's don't?


BTW - I've ordered 760x axle assemblies from my local crack dealer....They were cheaper than the NAPA replacement CV shafts! [D'OH!]

Yup, mine were almost the same price as new CV shafts, and I got to keep the CV's as spares, rather than turning them in for a core charge.



Thanks for all the info.

MaineZJ
10-20-2004, 01:47 PM
because a ujoint has 2 axis of movement, when it's operated at an angle, the output rotation isn't constant.
a CV has more axis of movement and has a more constant output rotation (given the name, constant velocity)

robselina
10-20-2004, 03:05 PM
because a ujoint has 2 axis of movement, when it's operated at an angle, the output rotation isn't constant.
a CV has more axis of movement and has a more constant output rotation (given the name, constant velocity)

Got me thinking, going to run OT for a sec here...running a regular u-jointed double cardan front driveshaft on a full-time rig would result in vibes or howl by nature wouldn't it? The two upper joints making the double cardan joint are 90 degrees out of phase, so their sinusoidal component cancels out. The shaft itself is 'constant velocity' due to this. however, the third joint at the pinion, where the stock CV joint is would then introduce a sinusoidal velocity component to the front axle, or am I looking at this wrong?

MaineZJ
10-20-2004, 05:58 PM
that's why the pinion is supposed to point right at the transfer case. there "shouldn't" be any angle to that joint at normal ride height.

you are correct. when something is lifted and the pinion isn't rotated up, people get vibrations, and that's what it's from

robselina
10-20-2004, 06:17 PM
that's why the pinion is supposed to point right at the transfer case. there "shouldn't" be any angle to that joint at normal ride height.

you are correct. when something is lifted and the pinion isn't rotated up, people get vibrations, and that's what it's from

DUH! Can't believe I didn't think of that....explains why a budy with a 249 has some issues though, since his pinion angle isn't exactly right (compromised to keep caster close to spec)+-

AnotherZJ
10-21-2004, 08:26 AM
because a ujoint has 2 axis of movement, when it's operated at an angle, the output rotation isn't constant.
a CV has more axis of movement and has a more constant output rotation (given the name, constant velocity)

So, then, you're saying I would still have binding with the 231, but only when I am in 4wd, correct?

Would manual hubs also be a solution?

MaineZJ
10-21-2004, 09:38 AM
the 249 creates some issues as it gets older. the VC doesn't slip enough to have the front and rear shafts turn at different enough speeds. on dry pavement this creates binding- wether you have CV's or ujoints.
a 231 allows 2wd, so there is no power sent to the front shaft, so there isn't any binding. pop it into 4, drive down the pavement, and you got binding.

locking hubs just makes it so the front tires don't turn the axle (or vise versa)

AnotherZJ
10-21-2004, 11:38 AM
the 249 creates some issues as it gets older. the VC doesn't slip enough to have the front and rear shafts turn at different enough speeds. on dry pavement this creates binding- wether you have CV's or ujoints.


I know of the VC problems with 249's, and this is something I tested before buying the jeep earlier this year. (Turned some tight circles on dry pavement). No issues.

I had no issues with my CV shafts. I pulled the CV's out, put the U-jointed shafts in and I immediately had the binding issues. Unless I didn't notice it before I put the shafts in (but it is very noticeable), or the CV's "masked" it more than the U-joints do.