H3 Transmission bit the dust!

[navaro1982]

I just bought 33s for my Hummer a few weeks ago and today my trans bit the dust(I think) I was cruising at 65 and all of the sudden my RPMs shot up and it was like my vehicle went into neutral. So I threw in in neutral and pulled to the side of the road. I waited a minute and cranked it back up. I then put iit in Drive but it just had high RPMs and when I put it back in Drive it was grinding through reverse. So it seems like I may be getting a news trans and I hope that’s all!


Sent from my iPhone using Tapatalk

 

[atvspeed4]

I just bought 33s for my Hummer a few weeks ago and today my trans bit the dust(I think) I was cruising at 65 and all of the sudden my RPMs shot up and it was like my vehicle went into neutral. So I threw in in neutral and pulled to the side of the road. I waited a minute and cranked it back up. I then put iit in Drive but it just had high RPMs and when I put it back in Drive it was grinding through reverse. So it seems like I may be getting a news trans and I hope that’s all!


Sent from my iPhone using Tapatalk

With the engine off but key on trying putting into 4 hi lock. Then once in 4 hi lock, start truck and put in gear. If it drives forwards fine you may have just blown the CV joint on driveshaft or a front CV. I've done both and had similar symptoms

 

[navaro1982]

With the engine off but key on trying putting into 4 hi lock. Then once in 4 hi lock, start truck and put in gear. If it drives forwards fine you may have just blown the CV joint on driveshaft or a front CV. I've done both and had similar symptoms

That worked! So I may have some hope! Thank you very much!


Sent from my iPhone using Tapatalk

 

[navaro1982]

Let me also add this when it happened going down the road I threw it in neutral to pull over and looked down to see it was actually in reverse! I put it in neutral and went to the side of the road. I did what was said above once I got it towed home and it will drive in 4 high. Would it go in Reverse going down the road and still be the CV joint on the drive axel?


Sent from my iPhone using Tapatalk

 

[atvspeed4]

Let me also add this when it happened going down the road I threw it in neutral to pull over and looked down to see it was actually in reverse! I put it in neutral and went to the side of the road. I did what was said above once I got it towed home and it will drive in 4 high. Would it go in Reverse going down the road and still be the CV joint on the drive axel?


Sent from my iPhone using Tapatalk

Yes

 

[navaro1982]

Yes

I just watched a YouTube video on how to replace it and it seems pretty simple. Let’s hope so!


Sent from my iPhone using Tapatalk

 

[650Hawk]

I was cruising at 65 and all of the sudden my RPMs shot up and it was like my vehicle went into neutral. So I threw in in neutral and pulled to the side of the road. I waited a minute and cranked it back up. I then put iit in Drive but it just had high RPMs and when I put it back in Drive it was grinding through reverse.

I had the same thing happen on my wife's Tahoe; turned out the transfer case was shifting into neutral, not the trans. Encoder motor was the culprit. Just another possibility if you don't find a CV joint bad.

 

[navaro1982]

I had the same thing happen on my wife's Tahoe; turned out the transfer case was shifting into neutral, not the trans. Encoder motor was the culprit. Just another possibility if you don't find a CV joint bad.

I just replaced the cv joint and it still does the same thing. The cv joint boot was thrown into the under care age of my H3 so it had to be replaced regardless. So I cranked it up and put it in Drive with no power to the wheels and when I put it back into park it makes a loud grinding noise. This sucks!


Sent from my iPhone using Tapatalk

 

[atvspeed4]

I just replaced the cv joint and it still does the same thing. The cv joint boot was thrown into the under care age of my H3 so it had to be replaced regardless. So I cranked it up and put it in Drive with no power to the wheels and when I put it back into park it makes a loud grinding noise. This sucks!


Sent from my iPhone using Tapatalk

You need to check both cv axle shafts AND the drive shaft cv that is closest to the transfercase. When you ruin the driveshaft cv it can spin inside the cup but not provide power to the front wheels. Post up after checking that out and we can keep moving forwards on things to check.

 

[alrock]

You need to check both cv axle shafts AND the drive shaft cv that is closest to the transfercase. When you ruin the driveshaft cv it can spin inside the cup but not provide power to the front wheels. Post up after checking that out and we can keep moving forwards on things to check.

And with the driveshaft spinning when you put it in park you'd get that grinding noise from the transmission.

 

[navaro1982]

And with the driveshaft spinning when you put it in park you'd get that grinding noise from the transmission.

From what I can tell the trans is fine. I can lock it in 4 High and drive around my driveway.


Sent from my iPhone using Tapatalk

 

[navaro1982]

You need to check both cv axle shafts AND the drive shaft cv that is closest to the transfercase. When you ruin the driveshaft cv it can spin inside the cup but not provide power to the front wheels. Post up after checking that out and we can keep moving forwards on things to check.

I have a guy coming to check it out tomorrow. He thinks my transfer case may need to be rebuilt.


Sent from my iPhone using Tapatalk

 

[atvspeed4]

I have a guy coming to check it out tomorrow. He thinks my transfer case may need to be rebuilt.


Sent from my iPhone using Tapatalk

That doesn't seem to make sense unless the slide collar was dropping into the neutral position which isnt a rebuild thing more of just a shifter fork or encoder motor but what makes that unlikely is that when you request 4hi lock it is changing range no problem and letting you drive. Have you gone offroading recently? When it's in all wheel drive and you say it's not moving is the front drive shaft spinning? That could mean you ruined the front diff

 

[navaro1982]

That doesn't seem to make sense unless the slide collar was dropping into the neutral position which isnt a rebuild thing more of just a shifter fork or encoder motor but what makes that unlikely is that when you request 4hi lock it is changing range no problem and letting you drive. Have you gone offroading recently? When it's in all wheel drive and you say it's not moving is the front drive shaft spinning? That could mean you ruined the front diff

I haven’t been. I just put 33” tires on it and the only thing I can guess is the bigger tires helped whatever was weak break.


Sent from my iPhone using Tapatalk

 

[4speedfunk]

Your front diff is smoked. That’s why it only moves in 4HI-Lock. The grinding you hear in 4HI-Street is the front driveshaft spinning the broken parts inside the front axle housing.
In 4HI-Street mode, the H3 t-case sends all the power to the axle that it thinks is spinning in the mud. With a blown front diff...the t-case thinks your front tires are spinning in the mud. It is doing exactly what it should and is sending all the power to the front axle. So the t-case is working perfectly. This function is 100% mechanical btw (not electronic).
Drain the front diff to see if chunks fall out. Front diffs fail quite often and your symptoms are very normal for this type of failure. Most likely it’s teeth off the ring gear or a broken stub shaft on the drivers side.
Half-shafts, driveshafts, and t-case are probably okay. These parts tend to outlast the front diff by quite a good margin.

 

[navaro1982]

Mechanics just left my house and said it’s my differential. With that I ask should I just replace it, rebuild, or rebuild with better parts?


Sent from my iPhone using Tapatalk

 

[atvspeed4]

Mechanics just left my house and said it’s my differential. With that I ask should I just replace it, rebuild, or rebuild with better parts?


Sent from my iPhone using Tapatalk

If its aluminum diff replace it. Usually when they go they can stress the housing or do other damage from metal chunks.

 

[4speedfunk]

You can rebuild or replace. But you can’t rebuild with better parts...because there are none. The only real upgrade is to replace the alum case with a cast iron version from an 09-10 model.
I rebuild these diffs daily and both the alum and cast iron versions are subject to the same sort of failures. They are undersized for a 6000 lb truck, and larger tires make things even worse. There is no golden cure. All you can do is rebuild it and try to keep a light foot on the throttle.
Many H3 off-roaders keep a spare front axle on hand all the time, and periodic swaps/rebuilds are just part of the game. It sucks but that’s the reality of owning & wheeling an H3.

 

[4speedfunk]

One nice thing is that parts are very available and they are easy to work on. A rebuild will run approx $200 to $600 in parts and bench labor should be in the $300 range.
I say “bench” labor because most of the time, my customers ship them to me, or walk-in with the diff already pulled from the truck. You can add another $200 or so to the labor if the axle has to be pulled from the truck.
It’s often faster (less downtime) and cheaper to simply swap in a good used diff.

 

[atvspeed4]

I am not sure on shipping cost but I think I have a few good aluminum front diffs with 4.56 gears somewhere let me know if you are interested. As soon as we buy a wheeling H3 we pull diff and put in our HD upgrade so we can have fun on 37s

 

[navaro1982]

I am not sure on shipping cost but I think I have a few good aluminum front diffs with 4.56 gears somewhere let me know if you are interested. As soon as we buy a wheeling H3 we pull diff and put in our HD upgrade so we can have fun on 37s

Yes sir please let me know!


Sent from my iPhone using Tapatalk

 

[SlcHummer]

As soon as we buy a wheeling H3 we pull diff and put in our HD upgrade so we can have fun on 37s

can I get a link to that HD upgrade or maybe sell you my H3 so you can pull the diff, install the HD upgrade, then buy back my H3? lol