Best option to keep a HP Dana 30 alive?

Best choice to keep a Dana 30 alive?

  • Open Diff

    Votes: 1 12.5%

  • True Trac LSD

    Votes: 1 12.5%

  • Selectable Locker

    Votes: 5 62.5%

  • Auto Locker

    Votes: 1 12.5%
  • Total voters
    8
G

GASnBRASS

TJ Enthusiast
Joined
Apr 6, 2017
Messages
688
Location
Minnesota
Currently have a HP Dana 30 with an open diff, chromoly shafts, 4.10 gears and 33's. I know if the wheels are turned and spinning and then suddenly gain traction it often blows up the shaft u joint ears, so would an LSD or locker actually minimize the risk of blowing up a shaft or the gears from excessive wheel speed? Are there times when a locker would actually over stress the shafts?

Poll for those who like to vote.
 
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It is very common to reliably run a Dana 30, locker and 35" tires with cromoly shafts, 5-760 u joints and proper gearing for the transmission. At that point, if the Dana 30 isn't surviving then the answer is likely a larger axle. This applies just as well to the marginally stronger HP30.
 
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A selectable locker would likely reduce the amount of scenarios in which you get into a wheel speed situation. An auto locker would be fine, but it could engage suddenly and quickly stress the system. If cost isn’t the biggest factor, I would always choose selectable, front and rear.

If you’re truly worried about blowing up the shafts, there are stronger options. There may be a 30 spline option for Dana 30 shafts that you can go with, which would give you larger inner shafts. You would need a new carrier for 30 spline axles.
Companies like RCV offer CV axle shafts in chromoly that are very difficult to destroy by torque alone. You can even get them made in 300M (stronger than chromoly) if you have the cash to blow.
 
The Dana 30 HP or LP is fine with a locker, auto or selectable, and 35" tires once you upgrade the shafts to a chromoly like 4340. I installed Warn's 27 spline 4340 shafts (no longer available) into my previous TJ's front LP Dana 30 and beat the snot out of them with 35's and auto locker and never had a problem.
 
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I just like polls, but I would think selectable gives you the best options. I like to crawl whenever possible and I used to try and use a lot of momentum when I had open diffs and no winch and typically it just got me more stuck. For you guys with traction, I would think if you used momentum and weren't just hopping that would snap axles fairly easy. Just my opinion though.
 
DieselJeep said:
... For you guys with traction, I would think if you used momentum and weren't just hopping that would snap axles fairly easy. Just my opinion though.
Click to expand...

What happens in Moab? If there was ever an environment where traction would reveal weaknesses in a locked up drivetrain, Moab is the place.
 
I re-read the post and I would think a locker could over stress poorly heat treated 4340 shafts, but that would also be my preference. I'm not sure that's your point, but the way it's worded and in general I would rather have a locker capable of overstressing a shaft than a shaft that can handle more stress than my expensive and hard to install selectable locker.
 
I was thinking more along the lines of rotational mass inertia (a large spinning tire stopping abrutly) is more likely to break an axle shaft than just brute torque while climbing over something. If that's the case, a locked front axle should be less apt to snap a shaft. I'm also wondering if there's a time when both tires have solid grip in a tight turn that the difference in turning radius binding would cause any damage, in which case a selectable would be preferred. Perhaps a LSD would be softer on the driveline in such instances.
 
GASnBRASS said:
I was thinking more along the lines of rotational mass inertia (a large spinning tire stopping abrutly) is more likely to break an axle shaft than just brute torque while climbing over something. If that's the case, a locked front axle should be less apt to snap a shaft. I'm also wondering if there's a time when both tires have solid grip in a tight turn that the difference in turning radius binding would cause any damage, in which case a selectable would be preferred. Perhaps a LSD would be softer on the driveline in such instances.
Click to expand...

Again, Moab.
 
jjvw said:
Again, Moab.
Click to expand...
Care to elaborate? I've never wheeled in Moab, so I have no idea if torque under traction (ie tight turns or climbs on hard rock) breaks stuff more often or if it's wheel spin inertia (spinning in mud and the tire grabs traction) that breaks stuff.
 
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GASnBRASS said:
Care to elaborate? I've never wheeled in Moab, so I have no idea if torque under traction (ie tight turns or climbs on hard rock) breaks stuff or if it's wheel spin inertia (spinning in mud and the tire grabs traction) that breaks stuff.
Click to expand...

Steep climbs, tight turns, lots of wheel travel. Slow and fast. Wheel spin, crawling finesse, inertia bumps. All of this is on 40 grit sandpaper that can sometimes make pavement seem like an ice rink. And many of us do it locked up the whole day.
 
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jjvw said:
Steep climbs, tight turns, lots of wheel travel. Slow and fast. Wheel spin, crawling finesse, inertia bumps. All of this is on 40 grit sandpaper that can sometimes make pavement seem like an ice rink. And many of us do it locked up the whole day.
Click to expand...
So under those conditions when are you most likely to see front axle shafts break? Under high torque stress where the wheel is stopped or barely moving but the engine is high throttle and T-case in low range? Or when a spinning wheel makes contact and stops abruptly (either straight or turned)?
 
GASnBRASS said:
So under those conditions when are you most likely to see front axle shafts break? Under high torque stress where the wheel is stopped or barely moving but the engine is high throttle and T-case in low range? Or when a spinning wheel makes contact and stops abruptly (either straight or turned)?
Click to expand...

That's an interesting question. In this high stress environment, how common is it to tear apart the drive train? ;)
 
Ultimately I'd like to know if it's multiplied torque that breaks front shafts, or wheel inertia. I've never wheeled in Moab and likely never will, so I don't have any personal knowledge of what goes on out there, but the description of the wheeling out there seems to imply that there is both high torque or high wheel speed situations. If inertia breaks 'em, then a locker would help mitigate that. If brute torque does, then an open diff may be better.

Maybe I'm just lousy at reading between the lines.
 
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It boils down to there being not nearly as much breakage in high traction situations as some are imagining there is. Install some chromoly front shafts and you're good to go with 35's and a locker.
 
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