GM IFS: What actually breaks?

WrenchMonkey · 05-18-2013, 10:13 PM

New-to-me tow rig is an 02 Suburban 2500 with the big 8.1.

I've developed an incredible itch to crank up the torsion bars and stuff a set of 35s under it. Combination tow rig and light-offroad puppy-bus.

I know the IFS isn't exactly the hot ticket on the trails, but I assume the 2500 stuff is stronger than the half-ton, and this would only be rutted-dirt-road type of wheeling.

The worry is, this IS the tow rig. If/when it breaks, it has to be fixed to get it home.

So, what breaks, and how field-repairable is it? I assumed it was mostly CV half-shafts. Carry spares, swap em out, not so bad. Or, since they flange-mount to the diff, can't you just unbolt em and drive on in 2wd?

Doing a little research, I guess the streering linkage is fragile too. I can change out the steering on my XJ in about 15 minutes flat. Is the Burban stuff as easy?

Anything else? Any experiences?

Thanks all!

Robert

Jonesy · 05-19-2013, 09:42 AM

I know the biggest issue from being around the local diesel pulling trucks, is the tie rod ends and associated components. Under a hard load in 4wd the wheels will toe in several inches. There are several companies that offer upgraded components specifically for this issue. Other than that the only other upgrade the pullers do is a locker in the front. Not sure how that abuse correlates to the abuse we put on them off road.

93 Krawler · 05-19-2013, 10:20 AM

I don't know the differences between a 1993 and 2002, but I put my 93 IFS through hell. I never broke a shaft. I did bend the tie rod, so I welded a small angle iron on it. If I can make it through rail bed in Harlan, I'd say you should be ok doing light off-road.

I had to put a 6" lift on mine to run 35's. I would assume your 3/4 ton sits higher than my 1/2 ton did.

I would upgrade the steering components and put the biggest tire you can fit under it without raising the torsion bars. My .02...

biggin69 · 05-19-2013, 10:56 AM

X2 on the torsion bars. It will ride like hell if you crank them up.

underpowered · 05-19-2013, 10:56 AM

most bend/break Tie rod ends. CV shafts can break, especially on cranked TB's.

If one breaks you can swap it out, or carry a spare stub shaft to get home in 2wd. just like your XJ, they use unit bearings and rely on the hub nut to hold it all together. if you pull the shaft, good chance your unit bearing will fail on the drive home.

otherwise, not many real trail breaks i have heard of with the IFS.

however, if you decide to crank it, be prepared to replace ball joints on a regular basis.

you can fit 33's with only a little crank, that is the route i would go, 35's won't much it much better off road than the 33's will.

WrenchMonkey · 05-19-2013, 01:18 PM

Quote:

Originally Posted by 93 Krawler

I don't know the differences between a 1993 and 2002, but I put my 93 IFS through hell. I never broke a shaft. I did bend the tie rod, so I welded a small angle iron on it. If I can make it through rail bed in Harlan, I'd say you should be ok doing light off-road...

That makes me feel better. I won't be doing anything like that.

Quote:

Originally Posted by 93 Krawler

I had to put a 6" lift on mine to run 35's. I would assume your 3/4 ton sits higher than my 1/2 ton did.

I would upgrade the steering components and put the biggest tire you can fit under it without raising the torsion bars.

I think I can fit a 33 as-is, with just a little rubbing. I know if you crank the bars all the way (like 3" lift) the ride goes to schidt. But I've read that an inch or two isn't too bad, and that might be all I need.

The upside is that if I crank it and hate it, I can always turn em back down.

I can fiddle with the lift, clearance and ride compromise. I just want to be ready for whatever trail breaks I might see.

Thanks for the insight guys!

Hope Springs Hauler · 05-19-2013, 01:46 PM

Speaking from the "I have a 2500HD on 33s" viewpoint, there is some tuck n trim to the bumpers and wheel well liners.

The weak stuff is:
Pitman and Idler arms
Tie rods
Unit bearings wear prematurely

I've avoided popping halfshafts, but I don't do boosted launches or offroad it, just pulling trailers back to remote lots

hotrod · 05-20-2013, 09:44 AM

I drag race my lb7 and I have tie rod sleeves and straight center link to keep from the "duramax wave" when leaving the line under boost. Same concept as before. If I were to offroad it, I'd want at least tie rod sleeves. You can get them anywhere, but I suggest merchant-automotive.com they are good people.
I also lowered mine 2/3 to get the cv shafts straight in the front

hate on...

Not my truck, but an example.

05-18-2013, 10:13 PM	#1
WrenchMonkey Mechanical Animal - CORE Member - - Moderator - Join Date: Feb 2008 Location: Beechmont Posts: 1,883	GM IFS: What actually breaks? New-to-me tow rig is an 02 Suburban 2500 with the big 8.1. I've developed an incredible itch to crank up the torsion bars and stuff a set of 35s under it. Combination tow rig and light-offroad puppy-bus. I know the IFS isn't exactly the hot ticket on the trails, but I assume the 2500 stuff is stronger than the half-ton, and this would only be rutted-dirt-road type of wheeling. The worry is, this IS the tow rig. If/when it breaks, it has to be fixed to get it home. So, what breaks, and how field-repairable is it? I assumed it was mostly CV half-shafts. Carry spares, swap em out, not so bad. Or, since they flange-mount to the diff, can't you just unbolt em and drive on in 2wd? Doing a little research, I guess the streering linkage is fragile too. I can change out the steering on my XJ in about 15 minutes flat. Is the Burban stuff as easy? Anything else? Any experiences? Thanks all! Robert __________________ DIRTY DEEDS, DONE DIRT CHEAP Whatever doesn't kill you makes you stranger

05-19-2013, 09:42 AM	#2
Jonesy Join Date: Dec 2010 Location: Piner, KY Posts: 141	I know the biggest issue from being around the local diesel pulling trucks, is the tie rod ends and associated components. Under a hard load in 4wd the wheels will toe in several inches. There are several companies that offer upgraded components specifically for this issue. Other than that the only other upgrade the pullers do is a locker in the front. Not sure how that abuse correlates to the abuse we put on them off road. __________________ JT Jones 83 Toyota - beater 87 Toyota Truggy

05-19-2013, 10:56 AM	#4
biggin69 Really??? Join Date: Sep 2009 Location: Cincy Posts: 678	X2 on the torsion bars. It will ride like hell if you crank them up. __________________ One Country, One Flag, One Language... LIKE IT OR LEAVE IT!!!

05-19-2013, 10:56 AM	#5
underpowered They call me......Scuba Join Date: Sep 2010 Location: Burlington, KY Posts: 292	most bend/break Tie rod ends. CV shafts can break, especially on cranked TB's. If one breaks you can swap it out, or carry a spare stub shaft to get home in 2wd. just like your XJ, they use unit bearings and rely on the hub nut to hold it all together. if you pull the shaft, good chance your unit bearing will fail on the drive home. otherwise, not many real trail breaks i have heard of with the IFS. however, if you decide to crank it, be prepared to replace ball joints on a regular basis. you can fit 33's with only a little crank, that is the route i would go, 35's won't much it much better off road than the 33's will. __________________ beat up rusted out k5

05-19-2013, 01:46 PM	#7
Hope Springs Hauler Join Date: Jul 2008 Location: Hamilton, OH Posts: 431 Images: 16	Speaking from the "I have a 2500HD on 33s" viewpoint, there is some tuck n trim to the bumpers and wheel well liners. The weak stuff is: Pitman and Idler arms Tie rods Unit bearings wear prematurely I've avoided popping halfshafts, but I don't do boosted launches or offroad it, just pulling trailers back to remote lots __________________ 1988 Suzuki Samurai on propane FJ 40 axles (4.10) 5.14 tcase 36" TSL SX

05-19-2013, 10:20 AM	#3
93 Krawler >>>PMC<<< - CORE Member - - Administrator - Join Date: Sep 2010 Location: Ross, OH Posts: 2,069 Images: 1268	I don't know the differences between a 1993 and 2002, but I put my 93 IFS through hell. I never broke a shaft. I did bend the tie rod, so I welded a small angle iron on it. If I can make it through rail bed in Harlan, I'd say you should be ok doing light off-road. I had to put a 6" lift on mine to run 35's. I would assume your 3/4 ton sits higher than my 1/2 ton did. I would upgrade the steering components and put the biggest tire you can fit under it without raising the torsion bars. My .02...

05-20-2013, 09:44 AM	#8
hotrod Diesel guy Join Date: Jul 2009 Location: Bridgetown Posts: 241	I drag race my lb7 and I have tie rod sleeves and straight center link to keep from the "duramax wave" when leaving the line under boost. Same concept as before. If I were to offroad it, I'd want at least tie rod sleeves. You can get them anywhere, but I suggest merchant-automotive.com they are good people. I also lowered mine 2/3 to get the cv shafts straight in the front hate on... Not my truck, but an example. __________________ 2013 RZR S