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H3 Cv joint or differential

Randy Tolbert

Probationary Member
Messages
3
Hey everyone
My wifes h3 wont drive unless it is in 4 high lock. Got under it and found cv joint boot torn on passenger side. The differential seal is severely damaged as well. It looks like the cv joint has slipped out of diff. Is this possibe or is the diff toast. I drained fluid from diff and found some fine silver debri but nothing big like pieces or chunks
 

alrock

El Diablo
Staff member
Messages
10,442
Location
Scottsdale
If the CV joint is out of the diff, then you definitely start with the CV. It won't move forward without that CV intact, so Happy Hummer is right on target.
 

4speedfunk

Well-Known Member
Messages
4,212
Location
Tardville
When H3's break something in the driveline...they will not move without 4HI-Lock. Probably just sits still and grinds, right?

Half-shafts can come "unplugged" from the diff. Grab a new pair of shafts. Grab a pair of axle seals. Grab some diff oil. Saturday afternoon project...not too tough.

Do both sides. Sure as $hit, the other side will probably fail within 5k miles...so while you got it apart, do em both. Also check the ball joints, UCA & LCA bushings, hubs, outboard diff bushings, and center crossmember bushing. These are often toast by 80k miles, and now is a perfect time to install some aftermarket replacements (Outfitter Design). Such is life with an H3...very high-maint vehicle. Plan on a total front suspension rebuild every 80k. Longer if babied. Shorter if abused.
 

4speedfunk

Well-Known Member
Messages
4,212
Location
Tardville
And longer if SAS'd??
No...probably about the same. The difference is the parts are very cheap, universal, and easy to source and work on. There are very few bushings to deal with (which IMO causes many of the IFS issues). With the SAS, you don't have CV boots, A-arms, or a steering rack. But, you still got u-joints. You still got tie-rods. You still got hub bearings. These things will always need periodic service and/or replacement. At least on the solid axle all of this stuff has grease fittings, and you can disassemble it and re-lube the hubs, rather than simply waiting for them to fail.

A common problem with the stock IFS is...when it fails, you're done! The truck will often be "un-driveable"...leaking, binding, or simply grinding big chunks into small chunks on the drive home. A side benefit of the SAS is what I call "LIMP-HOME-ABILITY". If something internal does break...you can un-lock the hubs, pull the driveshaft, and drive forever with the front axle completely shut off. This gives you the option to get home without a tow-truck, and it limits the grinding action that occurs with the full-time IFS. When these little mishaps occur, it often means dropping a grand or more to fix it (with either an IFS or an SAS truck). The difference is, you can still drive the SAS to/from work until you can get around to fixing it. The stock IFS rig on the other hand, is a lawn ornament until you fix it.
 
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