Cold Weather - Sticks in 4wheel lock.

[clickclickboom]

Here's a weird one for you. It seems that whenever the temp is very cold (IE 15 or below) when I start the truck up in the morning, or coming home from work, the truck appears to be stuck in 4wheel lock. It binds/ pulls going around corners. After driving for a few minutes the problem seems to solve itself.

I've tried shifting between 4 high, and lock and that doesn't seem to make a difference. I also don't hear a clunk when switching between the two as i'd expect. I've also tried shifing it in 4 high lock and low lock, and driving forward and reverse a few feet, and that didnt' seem to have any effect either.

It acts like my XJ would when I'd shift out of 4wd, and it take a bit of driving before completing the shift. The forward/ reverse trick often worked there.

Only seems to do this in the cold, any ideas?

 

[4speedfunk]

Move somewhere warmer!

(I'm just south of you)

 

[clickclickboom]

Maybe your onto something. Time to head to the beach.

 

[RamRod]

I have been having the exact same problem, been going through a few things to try and figure it out, haven't nailed it down yet

So far I tried replacing the CV (boot was ripped anyway) & replaced the power steering fluid (it looked like coke and needed it!).


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[clickclickboom]

I replaced my tc fluid if that helps with mobile 1 atf. Made no difference, but it was black so needed changed anyways.

 

[alrock]

Wondering if it is stuck in 4 high lock, but perhaps with a worn shift fork or other components where it allows it to slip to unlock under warmer conditions. I'd recommend getting under the truck when it's cold and have someone try the three modes and look/listen for the mode changes.

 

[deserth3]

Early H3 came with a plastic shift fork. If you hanger one they is an upgrade to a metal one. Think mine cost about 600b to have the dealer do it. But that was a few years back

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[clickclickboom]

This is a 09 h3t alpha

 

[RamRod]

This is a 09 h3t alpha

Strange, mine too


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[clickclickboom]

Adventure? Wonder if it's a problem with the tcase? Any other vehicle use the same 4:1?

 

[4speedfunk]

My 2008 AP t-case died at only 40K miles. A couple times (always during start-up), it acted like it was stuck in 4HI-lock, even though it had been in street mode for weeks. It was very subtle and felt exactly like you described (a Jeep XJ)...binding when turning. This always occurred in 4HI-street mode, and the t-case never had any issues switching modes. I would cycle through the modes...it would magically fix itself...and I wouldn't have any problems for months.

Then one day it started making tremendously harsh banging and binding sounds below 10 mph...both accel and decel (in 4HI-street). I mean CATSTOPHIC sounds, and I thought something was going to lock-up and drag the tires. The first time it happened I seriously thought I had been rear ended! It was so harsh that I had zero doubts...something inside the driveline had broken. I drained both axles...perfect. I drained the t-case...black, metallic fluid came out. Toast. To avoid the downtime, I decided to replace the entire t-case. The broken case is still on my bench, and it has loose parts rolling around inside it. For the record, it still shifted through all three modes. One of these days, I'll tear it apart...I suspect a chain got loose, and some links got into the gears. One thing for sure...whatever gizmo controls the front-to-rear bias had failed, because it was binding all the time.

 

[clickclickboom]

Do these tcases use a chain, it viscious couple like a np 249?

What's a rebuild cost on one of these, diy friendly?

Don't want to blow this thing to pieces on the freeway like I did the np231 in my xj, not exactly a $100 junkyard swap to fix.

When I drained the fluid it was black, but no metal was stuck to the drain plug, so think nothing catastrophic happened yet.

 

[4speedfunk]

They use a chain.
$400 for a rebuild (walk-in)
$600 if they gotta pull it (not difficult)
Fairly DIY friendly...getting parts might be the most difficult task. Some sort of home-made jig to clamp it in a vice is handy...it likes to roll around while you work on it.
I don't think the drain plug is magnetic (a separate magnet is elsewhere in the case).

Do a search on this forum...I think there are several tear-down/rebuild threads (with photos). Shift forks seem to be a common issue and many DIY guys have upgraded to the metal fork. I also recall several guys doing a chain replacement with no other mods. Schwarttzy has all the rebuild diagrams downloadable from his website in the "sponsers" section.

There are at least six different part numbers for H3 transfer cases...both AP and non-AP. I think all of the AP cases have been super-ceeded by the one below. It has the high-fill plug location, steel fork, 4:1 ratio, and fits Alphas and 5-cylinders, both AT and stick-shift.

Latest version of the 3394 4:1 Adv. Pak t-case....GM#24247592 (comes with fluid and actuator)
You will also need the mating gasket.....GM#15642511
While searching the net for t-cases, use the term "F-case" and "3393/3394"...these are terms that GM and Borg-Warner use.
The option code NR4 is the standard 2.6:1 ratio, and the NR6 is the Adv. Pak 4:1 ratio. V8 & 5-cly. do interchange, although there is a slight difference for exhaust clearance on the V8 cases.
I'm not aware of any other vehicles that use the 3393/3394.

 

[clickclickboom]

Thanks for the info, i'll do some more net searching to see if I can find any ideas.

Didn't seem to notice a problem this morning with it, but hard to tell with snow on the ground. Took it out at lunch, and it seems to be fine at first but once I drove ~100 yards I could feel it in 4whl lock. Went to turn into a parking lot, and felt/heard a loud clunk, and then it was fine again. Not sure if that's bad/ good.

Do you know of any good driveline shops around here if it comes to a rebuild?

 

[RamRod]

They use a chain.
$400 for a rebuild (walk-in)
$600 if they gotta pull it (not difficult)
Fairly DIY friendly...getting parts might be the most difficult task. Some sort of home-made jig to clamp it in a vice is handy...it likes to roll around while you work on it.
I don't think the drain plug is magnetic (a separate magnet is elsewhere in the case).

Do a search on this forum...I think there are several tear-down/rebuild threads (with photos). Shift forks seem to be a common issue and many DIY guys have upgraded to the metal fork. I also recall several guys doing a chain replacement with no other mods. Schwarttzy has all the rebuild diagrams downloadable from his website in the "sponsers" section.

There are at least six different part numbers for H3 transfer cases...both AP and non-AP. I think all of the AP cases have been super-ceeded by the one below. It has the high-fill plug location, steel fork, 4:1 ratio, and fits Alphas and 5-cylinders, both AT and stick-shift.

Latest version of the 3394 4:1 Adv. Pak t-case....GM#24247592 (comes with fluid and actuator)
You will also need the mating gasket.....GM#15642511
While searching the net for t-cases, use the term "F-case" and "3393/3394"...these are terms that GM and Borg-Warner use.
The option code NR4 is the standard 2.6:1 ratio, and the NR6 is the Adv. Pak 4:1 ratio. V8 & 5-cly. do interchange, although there is a slight difference for exhaust clearance on the V8 cases.
I'm not aware of any other vehicles that use the 3393/3394.

So much great info there!!

Thanks for the write up!


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[alrock]

Then one day it started making tremendously harsh banging and binding sounds below 10 mph...both accel and decel (in 4HI-street). I mean CATSTOPHIC sounds, and I thought something was going to lock-up and drag the tires. The first time it happened I seriously thought I had been rear ended! It was so harsh that I had zero doubts...something inside the driveline had broken.

It took me nearly a year to figure mine out with similar sypmtoms as the 2-3 instance of this happening were months apart and I couldn't replicate it. I suspected front diff and that wasn't it. It would be advisable to pull the transfer case now while the problem is (probably) small and tear it down. The parts total could be minor at this point vs. mine which is going to be a complete replacement.

 

[4speedfunk]

I know a great t-case guy in Mooresville., Not sure if he does removals/installs....but for bench work, he's da man.

 

[RamRod]

Move somewhere warmer!

(I'm just south of you)

Funny part is, I'll be moving to a warmer place at the end if the month!


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[clickclickboom]

I know a great t-case guy in Mooresville., Not sure if he does removals/installs....but for bench work, he's da man.

I've got no problem pulling it, if it comes to that I'll get in touch. Thanks for all the help. You hang out with anyone from mojo offroad? sure we probably know some of the same people.

 

[4speedfunk]

Yes...I know the Mojo crowd. The guy I'm talking about occasionally works at their shop. He's an older, Hemmingway-looking dude that smokes cigars. He builds NV-4500s and NP-205's for the jeepers and diesel puller guys...does great work. The funny thing is, his work area is spotless while the rest of the Mojo shop looks like a crap hole. Its weird seeing a perfectionist surrounded by duct-tape & zip-tie guys! I'm a frequent visitor to Patterson Driveline (just down the road), and the same old dude built the tranny/t-case for a Cummins-powered TJ that the owner is building.

I actually want to take him my original t-case (still sitting on the bench), and see if he can convert the variable 4HI-Street mode to a fixed 2HI-locked mode. I've been thinking about this for quite some time, and I think it might be easier than trying to swap-out the entire case for some other 2WD case. The button on the dash would remain, and instead of full-time 4WD...it would activate a rear-only 2WD mode. Note this is a pretty extreme mod, and it does not really do much for stock H3's...but I'm running a solid front axle with lock-outs, and it sure would be nice to simply push the button, and un-lock the hubs for long-distance journeys.

 

[clickclickboom]

Too funny. I used to go down for jeep night every wed, but gas got expensive, bought a house, life got in the way. Haven't been down much. I've met him, think his name's jim? watched him tear apart a 205 one night.


On another note, after the bang yesterday everything seems to be fine, maybe whatever was hung up has fixed itself, i'll see what happens, and maybe drain the fluid and see how it looks. Wife's car is currently in the garage for some exhaust work, then I need to get the truck back in for the outfitter design steering reinforcement as well as a front diff fluid change.

Are you aware of anyone that makes a custom HD cover for the front? Put a solid cover on the rear, but haven't been able to find one for the front aam7. Figured the extra strength couldn't hurt.

Have to meet you at the mojo garage and take these things over the rock pile. They were less than enthusiastic about my choice of new ride

 

[4speedfunk]

Yeah. Wednesday nights used to be: "drink beer, tape our rigs together, and make fun of Hummers" night....not sure they do that anymore. Last time I stopped by there was a guy living in an RV in the driveway...cousin Eddie style.

That bang & release is the first sign that something ain't right...that's how mine started. I'm with Alrock on this...probably need to address it before it really does some damage.

Cover for the AAM-7? Nope. I sent a spare cover to Schwarttzy and he was going to make one...but I never heard anything more on the topic. IMO...it would be a big waste of effort...doubt if it would contribute to any strength improvement. However if you extended some steel off the cover toward the drivers-side and clamped on to that tube...that might help stiffen it up a bit. The bolt-on axle tube is a horrible idea, and there has never been an axle more in need of a truss. I got a cardboard one mocked-up...just sort of gave up on it (and anything to do with the IFS).

I won't be meeting you at Mojo. I have too many teeth to hang with those guys! But, you're more than welcome to hit my shop (12 minutes past Mojo on 37). The beer is always cold and we don't hate. Best of all...crescent wrenches are not allowed!

 

[clickclickboom]

They're a good group of guys with the occasional redneck hangers-on, and people looking for some free work. Some nice rigs, and certainly some just together enough to make it to the badlands. But, I get where your coming from.

Any interest in sharing your truss template? sounds like a good winter project.

I'm going to keep a close eye on the Tcase and look at the fluid this weekend, At least now I think we've identified the culprit. If I have any more trouble i'll pull it - just hurts as I've only had this thing 6 months, and I'm 99% sure the only wheeling it's ever seen was my 1 trip to land between the lakes last year.

Love to stop by sometime and gawk at your SFA setup. Looks like nice stuff.