welded rear breaks what first?

[rusmannx]

ok,
i'm 33's 4 inch lift.
planning a spring over this summer and want to go up to 36's or 38's.
if i weld the rear, what is the first thing likely to break.
or should i not have a problem?

 

[Jonx4x4]

Your biggest problem would be the welds coming loose and tearing up EVERYTHING. Ive seen it happen, it isnt pretty...

With the size tires youre aiming for, yeah, youre gona have breakage!

Thats just IMHO.

 

[moralien]

If you do a good job welding the 3rd I would think your axles would be the weak link.

If you plan on running 38's your best bet would be to run longfields. (Even though he may be a little flakey)

And you do know what happens when you snap an axle on a SF don't you. ???

 

[Jonx4x4]

But Ive seen very few people weld them correctly, though...

Breaking an axle on a SF gets interesting! Gets even more interesting when you do it going uphill. One of my friends lost his roof due to that... :-\

 

[hammerhead]

As a welder, doing the job isn't scary at all. As a finesse driver, breakage isn't much of a concern either. What I really question is driveability. How about asphault? Turning radius? Tire wear? Handling characteristics?

 

[rusmannx]

well,
i'm probably going to weld the rear end (front is open too) for the moab trip we're planning (august 15th).
i won't have the soa or 36's by then, but if even running 33's is going to be risky then i'll just do the trip open diffs.
my welder guy has welded countless rearends (demo derbies) and says he has never had on break.
i'm planning or using a light right foot in moab anyway, (it's in the mud i like to drive hard) so i don't suspect much damage (mechanical or body) even with the welded rear.

as far as street driving... it doesn't see much these days. living across the street from school and work, i only drive it a few miles to get to the mouth of the canyon. this is my first trip to moab (even though it's only a 7 hour drive from here) so i'm not to sure what to expect.

what would you guys do?

 

[geocrasher]

Well, I had to make this decision when I bought my Fj55 back. I could have had open, auburn limited slip, or welded. I chose welded. Its not back on the road yet, so I'll post how it goes. I live less than 2 miles from work, and will do very little driving on the road except around town here and there, and to/from work. I plan on running high pressure, around 35 lbs, in the rear, so the tires do not grab so bad around the corners. We'll see if it helps. I plan on carrying spare axle shafts if I can, and if I go on a hard core trail, I'll be carrying a spare carrier JUST IN CASE the third blows up. It did break when my friend first welded it, but just the welds broke. He had welded the spiders to the carrier, and that didn't work. But, he welded the spiders to each other, and has since had no problems.

Oh yeah the piggy is SOA on 35" BFG AT's, but will be some 36" MT's by next year

 

[rusmannx]

ever put magnets in your diff?
my friend does this to collect the debris if/when welds break.

 

[geocrasher]

Most vehicles come stock with one on the drain plug. If not I don't think it'd be a big deal to drop one in during 3rd member install. Maybe tack weld it so it can't move around?

 

[rusmannx]

i would think it would loose it's magnetism when heat is put to it like that... maybe some jb weld.
either way, now i'm thinking i won't weld it afterall so i don't have to worry about it.

 

[woody]

I've run a welded rear diff for 2 years with my 38.5 tires and have had no breakage. The welds have cracked tho, and I pop the rear cover ~2x per year to remove the bad chunks. It was done IN the truck tho, and I've got a MUCH better bench-welded center along for a spare that frankly I've been too lazy to install.

On road, air up the rear tires...lots. Tire wear suffers either way, may as well limit the scrub issues on corners and keep things in the center ribs.

The stock magnetic drain plug is great for little shavings and useless for chunks....lol

Run rear disc brakes and the busted axle issue is not as bad....bad, but at least you don't have it wandering out completely!

IMO, you won't have a problem...I'm HARD on my rig and I've experienced no breakage. (course, now I'm jinxed for BHCC....lol)

 

[rusmannx]

confidence restored.

 

[Eskimo]

I, too, am running a welded rear. did the 8 points where the spiders and side gears come together.

Now I'm on 38.5" SX like Woody, and I dont' even think about the diff back there.

Only difference is that I'm running a centered diff, with minitruck outers & disc brakes, but IIRC the axle shafts are similar in diameter.

 

[jm]

Well... I haven't had the same luck as woody... welded rear running 36s and took teeth off of both spiders (not pretty) and while the teeth were moving to the magnet and the low point of the diff one went between the ring gear and inspection cover resulting in a small hole. Yes, rear discs should control one of the potential problems.

That being said... I will be welding up another set of spiders for install shortly. Maybe I'll even post a pic of the damage to the last set.

jm

here's the pick of a bad spider...

 

[hammerhead]

Hey jm, How was that failed diff welded?

 

[hammerhead]

...I'm about to weld one and want all the input I can get.

 

[woody]

I just thrashed on my welded diff again this past weekend at BHCC...again, no breakage. And given the amount of rock rash I earned, this would have been the weekend it might've given out...

 

[hammerhead]

Is that the one you show on tech page? Welded to carrier? or welded eight points?
I have a carrier that has some chipped spiders and damaged cross pin holes. Also some gouges in the carrier itself. It can't be used as an open diff or as a lockright because of the unreliable cross pin holes. Everything else is OK. Would this be a good candidate for a lincoln locker?

 

[hammerhead]

*bump*

 

[woody]

8 points only, do not weld gears to case.

sounds like a perfect candidate!