Transfer case shift fork question

[lowtrac]

I've been doing some reading and haven't really found a consensus on this. I've had my 2006 H3 for a few weeks now. The steering feels heavy to me if you turn the wheel much farther than you would if you were making a normal turn. It is especially noticeable making tight turns like a drive-through. Steer it sharp enough and it requires more throttle to continue moving. I've steered all the way to lock and got out to check and the tires aren't hitting anything. It's got a torsion bar crank and some XD Rockstars with 285/65R18 Nitto Trail Grapplers. I bought it that way. I know it's full-time 4wd, so I didn't initially think much about the steering feeling heavy, plus the weight and width of this wheel and tire package can't be helping; but it's starting to worry me.

After reading some about the 2006 model year and the plastic shift fork I started wondering if it may actually be stuck in 4-high lock although the light on the dash shows 4-high. With the transmission in neutral I can switch among all three 4wd settings. It definitely goes into 4-low as evidenced by a short drive test. No question on that one. I can't really hear anything going between 4-high and 4-high lock though. I tried backing up 100 feet or so for good measure (in 4-high) with no noticeable change. I read in a post somewhere about a guy saying that he always shifted his transfer case into neutral then back to 4-high when it got stuck in 4-high lock. I tried that. The TC for sure went into neutral, dash indicator N as well as no movement of the vehicle in drive or reverse. I pressed the 4-high button and after hearing the clunk it was back to normal. I do think I feel a difference in the steering at this point but it may be placebo. The main part of this post is to ask if the TC would go into 4-low or neutral if the fork was broken? Is there any other way to determine if it's actually in 4-high lock?

At a cruising speed from 70-75 MPH I'm running about 2500 RPM. Is this a normal range? I'm calculating MPG based on the trip odometer reading divided by gallons of fuel at fill up. It's averaging around 14.5. Does that seem about right based on the wheel and tire package?

 

[4speedfunk]

Cruising speed, RPM, and MPG all sound normal. I've had a similar binding feeling before, when my t-case was on the fritz. Mine was not a shift-fork issue, however. Instead it was another internal issue with the t-case (and lots of debris & loose parts inside it). It was more than just a scuffing feeling. It was actual binding and releasing. This was quite noticeable because, I had owned the truck since new and I did not do any changes to make it appear. It just started doing it one day.

 

[650Hawk]

If, on pavement, you can turn at (or near) full lock without the truck jumping, stopping, and skipping, then you are not locked. Trust me, you WILL know it if you are locked on pavement as soon as you turn tight; it literally WON'T go. Try putting it in 4HI-lock and then turning tightly on the pavement; you'll see the difference. If there is no difference, then you have a transfer case problem, and it's not going into lock mode.

 

[DJinCO]

All of this sound quite normal. The tires are rather large so there is more weight from that; mileage and RPMs is consistent.

 

[lowtrac]

If, on pavement, you can turn at (or near) full lock without the truck jumping, stopping, and skipping, then you are not locked. Trust me, you WILL know it if you are locked on pavement as soon as you turn tight; it literally WON'T go. Try putting it in 4HI-lock and then turning tightly on the pavement; you'll see the difference. If there is no difference, then you have a transfer case problem, and it's not going into lock mode.

I'll try to shift to 4-high lock and steer tomorrow. Just this afternoon I steered to full lock on pavement and drove in a circle. It was able to do so, but you could tell it really didn't want to. If I understand correctly, when in 4-high theres a differential in the transfer case distributing 60 percent power to the rear and 40 to the front, correct? If this is the case, if I were to raise the front tires off the ground and put it in drive would all the power transfer to the front since there's no resistance? My theory is that only the front tires would spin if the transfer case was unlocked. I may not fully understand how the 4WD system works though. Just a thought.

 

[lowtrac]

Cruising speed, RPM, and MPG all sound normal. I've had a similar binding feeling before, when my t-case was on the fritz. Mine was not a shift-fork issue, however. Instead it was another internal issue with the t-case (and lots of debris & loose parts inside it). It was more than just a scuffing feeling. It was actual binding and releasing. This was quite noticeable because, I had owned the truck since new and I did not do any changes to make it appear. It just started doing it one day.

Thank you for verifying this. I would describe what this is doing as binding, but it doesn't fully lock up. When it starts to bind, you can power through it by giving it more gas. There's no popping or anything. There was no maintenance records with it so I have no idea when or if the fluids have been changed. I'm planning to change the fluids in both diffs and transfer case over the next couple of weekends. I'm curious to see how nasty it is. Maybe if some metal shavings come out I'll know what's up.

 

[4speedfunk]

It could also be a bad CV-joint or a problem with the front diff. Check the boots for a rip...grease will be flung all over the surfaces surrounding it.

T-case fluid will be nasty for sure...most of us have adopted a 25k mile fluid change regardless of GM's recommendations. For some reason the H3 t-case fluid does not last very long. Lastly...on 06-07 models, the fill plug is too low, and you cannot get the required amount of fluid into the t-case thru this hole. Instead you must get what you can thru the fill hole and then pour the rest into the t-case via the VSS (Vehicle Speed Sensor) hole. This problem was addressed on 08-later models by relocating the fill hole up higher on the case.

 

[lowtrac]

Great information. Thanks to all. I'll update as I check stuff out.

 

[Reloader]

Had a 3 that we took on trade at the Toyota stealership I used to work at that bucked and jumped when turning in parking lot. Was stuck in 4 hi loc. Needed new shift fork and slider assembly as fork had jumped over slider and that kept it in loc? No telling how long they drove it like that. Was easy fix though and no other damage to TC. Did find a split suction hose on internal lube pump. Always check the hose and check the intake screen for debris and clean it. Fork was a plastic one since 3 was an 06 or 07. I've adopted changing the transfer case fluid every other engine oil change so that's every 8K miles or less. Always dirty it seems.

 

[Reloader]

If I remember the fork was around $15, the slider was a c-note and that dam hose was like $30 or something at dealer. These are jobber prices which are typically 25% off list? Don't forget new TC to trans gasket.

 

[4speedfunk]

Here's the culprit...

Anytime you go to the trouble of a tear down...replace this plastic piece with an aluminum one. Reloader is spot on...the fluid pump tube and pickup are often sucked shut and clogged with shavings.

 

[06PullUouT]

Had a 3 that we took on trade at the Toyota stealership I used to work at that bucked and jumped when turning in parking lot. Was stuck in 4 hi loc. Needed new shift fork and slider assembly as fork had jumped over slider and that kept it in loc? No telling how long they drove it like that. Was easy fix though and no other damage to TC. Did find a split suction hose on internal lube pump. Always check the hose and check the intake screen for debris and clean it. Fork was a plastic one since 3 was an 06 or 07. I've adopted changing the transfer case fluid every other engine oil change so that's every 8K miles or less. Always dirty it seems.

Whoa, with every oil change? That sounds crazy, but I might look into adopting this practice!


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[Reloader]

Every other oil change. So about 8K miles on transfer case lube. Is always dirty looking.
Dex 6 is cheap. Rebuilding a case isn't . Buy yourself a good quality suction gun off tool truck or Napa store. Makes refilling very easy.

 

[06PullUouT]

Every other oil change. So about 8K miles on transfer case lube. Is always dirty looking.
Dex 6 is cheap. Rebuilding a case isn't . Buy yourself a good quality suction gun off tool truck or Napa store. Makes refilling very easy.

Ha, misread that...


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[lowtrac]

So, a weird thing happened.

I changed the front diff oil this past weekend. It was darker than the new stuff but nothing alarming. There was a bit of metal shavings on the drain plug magnet but not big chunks. No difference in steering feel. Tonight I decided to pull the front drive shaft to see for sure if I'm in 4HL. I left the front wheels on the ground since it looked like I could get to all the bolts without turning anything. I started at the CV end of the shaft and when I pulled out the last bolt it sort of "sprung" like it was under some torsional stress. Don't know if that is normal or not. Moved on to the front end and pulled the bearing cap straps. Then I pulled one of the bearing caps off. Oops. A couple of minutes later and a trip to Ye Olde tub of grease and it was back on. Fired it up, lights indicating 4H, dropped it in drive, and it rolled forward. Now I'm thinking it's a done deal. I've got the broken shift fork.

I'd read some threads about people talking about driving without the front shaft but no one seems to ever really do it. I figure this is as good a time as any so I go for a test drive. I pulled out of the driveway and turned, stopped, tried to go again and nothing. No motion forward or reverse, engine freely revving like I was in neutral. I put the transmission in neutral, hit the 4HL button, nothing. Back to neutral, went to 4LL, nothing. Thankfully I was only about 50 feet from my driveway so I hooked a tow strap to it and pulled it back home. I reinstalled the front shaft and went for another test drive. Everything seemed back to normal until I turned around in the cul-de-sac. About halfway through the turn I started to feel the familiar binding in the front end then there was a pretty loud pop. The binding went away and I went back home with no problems.

I don't know much about 4WD vehicles, but logic leads me to think that there's for sure problems with the transfer case. Do you guys think it's only the shift fork or something worse?

 

[Broken Halo]

New to the forum here. Can anyone DEFINITIVELY say if/when there was a change-over from a plastic to an aluminum shift fork? I been a member of 2 other forums for several years and depending on who's posts/threads you read I've seen everything from 'changed-over in 2008' to 'never changed-over, only used as a service part', to 'only used in Alpha's'. Sure would be nice to know once and for all. Thanks, and looking forward to becoming an active member.

 

[USMC_TOP]

I had the same thing go on mine for the most part. I bought a new case from GM problems gone. By the time you pay someone to split that case and repair it you can buy a new one that is updated with the good forks for 1700


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[4speedfunk]

Your description is not real clear. But, you should be able to drive anywhere with the front driveshaft removed...but only in 4HI-Locked or 4LO-Locked. In 4HI-Street the H3 should just sit still and rev. Take a closer look and you'll see the front output flange on the t-case will free spin, when you give it gas. Always use the parking brake because you have no PARK gear without the front driveshaft.

That tension in the driveline that you felt when you pulled the front driveshaft...was essentially the PARK gear. You released it. Be very careful, as the truck can roll away as soon as you pop the shaft loose.

 

[lowtrac]

Your description is not real clear. But, you should be able to drive anywhere with the front driveshaft removed...but only in 4HI-Locked or 4LO-Locked. In 4HI-Street the H3 should just sit still and rev. Take a closer look and you'll see the front output flange on the t-case will free spin, when you give it gas. Always use the parking brake because you have no PARK gear without the front driveshaft.

That tension in the driveline that you felt when you pulled the front driveshaft...was essentially the PARK gear. You released it. Be very careful, as the truck can roll away as soon as you pop the shaft loose.

What you describe is what I expected, but I was only able to drive about 50-75 feet without the front shaft before it quit pulling. No matter which mode I set the 4WD in I got no forward or rearward motion. I could hear the transfer case click each time I pressed a button but it reacted as if it were in neutral.

I drove it around today, probably about 60 miles, and there were a couple of pops when turning left. Thanks for the heads up on park. Getting run over would definitely ruin your day.


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[Burtor]

So, a weird thing happened.

I changed the front diff oil this past weekend. It was darker than the new stuff but nothing alarming. There was a bit of metal shavings on the drain plug magnet but not big chunks. No difference in steering feel. Tonight I decided to pull the front drive shaft to see for sure if I'm in 4HL. I left the front wheels on the ground since it looked like I could get to all the bolts without turning anything. I started at the CV end of the shaft and when I pulled out the last bolt it sort of "sprung" like it was under some torsional stress. Don't know if that is normal or not. Moved on to the front end and pulled the bearing cap straps. Then I pulled one of the bearing caps off. Oops. A couple of minutes later and a trip to Ye Olde tub of grease and it was back on. Fired it up, lights indicating 4H, dropped it in drive, and it rolled forward. Now I'm thinking it's a done deal. I've got the broken shift fork.

I'd read some threads about people talking about driving without the front shaft but no one seems to ever really do it. I figure this is as good a time as any so I go for a test drive. I pulled out of the driveway and turned, stopped, tried to go again and nothing. No motion forward or reverse, engine freely revving like I was in neutral. I put the transmission in neutral, hit the 4HL button, nothing. Back to neutral, went to 4LL, nothing. Thankfully I was only about 50 feet from my driveway so I hooked a tow strap to it and pulled it back home. I reinstalled the front shaft and went for another test drive. Everything seemed back to normal until I turned around in the cul-de-sac. About halfway through the turn I started to feel the familiar binding in the front end then there was a pretty loud pop. The binding went away and I went back home with no problems.

I don't know much about 4WD vehicles, but logic leads me to think that there's for sure problems with the transfer case. Do you guys think it's only the shift fork or something worse?

To summarize, it sounds like you have up to two problems which are possibly related;
1) Your transfer case is not shifting between modes
2) Your entire drive train is binding somehow

Since you were able to get some power to the rear wheels when the vehicle believed it was in 4H "free" mode, indicating that your transfer case was in a locked mode.

However, you then suddenly lost all power to the rear wheels, implying that your transfer case shifted back into a neutral or free mode.

Then when you pushed the dash buttons to indicate 4HL and 4LL, your transfer case was still acting like it was in a neutral or free mode.

So, you reattached your front drive shaft and your vehicle drove normally, indicating the transfer case was in 4H "free" mode.

But, tragedy struck again, and a binding feeling and a loud pop occurred, suggesting that your transfer case was locking up again.

Then the issue seemed to clear its self up, and you are perhaps back into 4H "free" mode again, just like your dash is telling you.

So, it seems possible that *if* an issue with a shift fork can cause spontaneous shifting between modes, then yes, you have a shifting fork problem.
I don't know if automatic and inconvenient transfer case shifting is a symptom of a broken shift fork, but I would certainly start by thinking about opening or rebuilding your transfer case.

Will you be doing the work yourself, or taking it to a shop?

 

[lowtrac]

To summarize, it sounds like you have up to two problems which are possibly related;
1) Your transfer case is not shifting between modes
2) Your entire drive train is binding somehow

Since you were able to get some power to the rear wheels when the vehicle believed it was in 4H "free" mode, indicating that your transfer case was in a locked mode.

However, you then suddenly lost all power to the rear wheels, implying that your transfer case shifted back into a neutral or free mode.

Then when you pushed the dash buttons to indicate 4HL and 4LL, your transfer case was still acting like it was in a neutral or free mode.

So, you reattached your front drive shaft and your vehicle drove normally, indicating the transfer case was in 4H "free" mode.

But, tragedy struck again, and a binding feeling and a loud pop occurred, suggesting that your transfer case was locking up again.

Then the issue seemed to clear its self up, and you are perhaps back into 4H "free" mode again, just like your dash is telling you.

So, it seems possible that *if* an issue with a shift fork can cause spontaneous shifting between modes, then yes, you have a shifting fork problem.
I don't know if automatic and inconvenient transfer case shifting is a symptom of a broken shift fork, but I would certainly start by thinking about opening or rebuilding your transfer case.

Will you be doing the work yourself, or taking it to a shop?

Yes. This is what I'm experiencing. I still haven't decided about doing it myself or taking it somewhere. I'm no stranger to spinning a wrench, and have done some transmission work, but have never touched a transfer case. I'm confident I can replace the shift fork, but if its anything else I'd be concerned. I don't, however, want to be "that guy" and show up at a transmission shop with my transfer case in a box asking them to fix it. I'll call around to some places and get a quote on changing the fork and deal with any other issues as they arise. I've seen used transfer cases with warranties for under $1000 so I doubt a shop would do a rebuild for less.

 

[4speedfunk]

I don't, however, want to be "that guy" and show up at a transmission shop with my transfer case in a box asking them to fix it.

Don't sell yourself short. You'll never find a guy that will give a $hit as much as you do. If you want it done right...do it yourself. The BW-3393/94 is not complicated. You can pull it out, and tear it apart in an hour or two. Count on a chain replacement and shift fork for sure...possibly more. Pay particular attention to getting the planetary gears indexed properly with the sun gear when you put it back together. Also make sure the chain is on in the right direction. Lastly, flush the entire thing with Brake-Kleen and clean the internal magnet off...check the pump pick-up screen for signs of being clogged...be clean.

You can download the manual from Schwarttzy...huge help. I can get you parts if you need them.

 

[GoBlueHummer]

Don't sell yourself short. You'll never find a guy that will give a $hit as much as you do. If you want it done right...do it yourself. The BW-3393/94 is not complicated. You can pull it out, and tear it apart in an hour or two. Count on a chain replacement and shift fork for sure...possibly more. Pay particular attention to getting the planetary gears indexed properly with the sun gear when you put it back together. Also make sure the chain is on in the right direction. Lastly, flush the entire thing with Brake-Kleen and clean the internal magnet off...check the pump pick-up screen for signs of being clogged...be clean.

You can download the manual from Schwarttzy...huge help. I can get you parts if you need them.

Should be quoted in every post.

 

[lowtrac]

Sometime soon.