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popping noise in 4lo

06 H3

a.k.a. "The Jackal"
Messages
9,506
Location
Meridian, ID
The other day when I went to rowher flats through the backside kyles H3 had a popping noise climbing steep hills.

I looked at the underbody as he climbed and noticed under heavy load the transfer case rotated and smacked against his skid making the popping noise. He doesnt not have the OEM skid, it is 1/4in plate bolted to the crossmembers so it does sit higher. Either way the case would rotate with the force.

Is this normal? Its almost like a bushing or mount is bad.
 

06 H3

a.k.a. "The Jackal"
Messages
9,506
Location
Meridian, ID
good point. if you think the diff bushing is bad, under load it will force the diff upwards and can affect the t case because they are connected...any other thoughts?
 

Zach

Mall Crawler
Messages
4,812
Location
So Cal
Most of the popping noises I've seen or heard have been the plastic shift fork. Bad crossmember bushing could be it. I know when my bolt fell out, the diff was moving up and down. Left it there till I could get one back in
 

SuperBuickGuy

Well-Known Member
Messages
3,403
Location
Woodinville, WA
only bad noises I've had required replacing the transfer case (2 links fell out of the chain, one got caught in the magnet, the other destroyed a couple gears). It was a popping sound too - especially under acceleration
 

alrock

El Diablo
Staff member
Messages
10,677
Location
Scottsdale
I haven't removed a transfer case, so pardon my newbie questions on this. But isn't the transfer case bolted directly to the transmission, which of course is bolted directly to the engine? If so, there should be a bit of play due to the give/take of the two engine mounts and the transmission mount. However, if any of those mounts have failed then the movement would increase.

Might be worthwhile to check engine movement by opening the hood, starting the truck, firmly holding the brakes and moving the transmission from P to R to D to see if the engine is rocking. Not sure how to necessarily check the transmission mount other than a visual check, but maybe a bottle jack and blocks of wood to raise it up and see if it moves?

Essentially, what I'm thinking is that a small amount of movement would occur but large amounts shouldn't. Transfer case shouldn't move solely due to a bad diff mount or propshaft, should it?
 

Zach

Mall Crawler
Messages
4,812
Location
So Cal
Also, might want to check the diff side brackets. They will cause okay in it too
 

06 H3

a.k.a. "The Jackal"
Messages
9,506
Location
Meridian, ID
ok guys, today Kyle came over and we put it in low. gas on and brake on and got the same popping noise. Then pulled the skid because it hit the skid when we did that and still got the noise. That cancelled the skid and case noise theory, I then pulled the front driveline to narrow it down between the t case and the diff and still got the pop so its from the tcase. Then I jacked up all 4 tires so none were touching the ground and put it in 4 lo and let the tires spin. if the t case is working properly you put the parking brake on and all tires should stop because the t case locks the front and rear wheels, his didnt. Which means his t case isnt locking it 50/50 from front to rear in 4hi locked and 4 lo locked and the pop is probably from a stretched t case chain or a chipped tooth on the gears.

Either way its time for a new t case. Not sure how it happened, I wonder if it was neglect from the previous owner or something else but we wheeled the same thing then I took all the optional lines and had no issues...Age or neglect?

So we called Zach and Oakland t case express and going with Zach seems to be a better deal due to warranty on the case and he can keep the old one vs. sending in his broken one as a core so he can fix it and have it ready for next time
 

SuperBuickGuy

Well-Known Member
Messages
3,403
Location
Woodinville, WA
ok guys, today Kyle came over and we put it in low. gas on and brake on and got the same popping noise. Then pulled the skid because it hit the skid when we did that and still got the noise. That cancelled the skid and case noise theory, I then pulled the front driveline to narrow it down between the t case and the diff and still got the pop so its from the tcase. Then I jacked up all 4 tires so none were touching the ground and put it in 4 lo and let the tires spin. if the t case is working properly you put the parking brake on and all tires should stop because the t case locks the front and rear wheels, his didnt. Which means his t case isnt locking it 50/50 from front to rear in 4hi locked and 4 lo locked and the pop is probably from a stretched t case chain or a chipped tooth on the gears.

Either way its time for a new t case. Not sure how it happened, I wonder if it was neglect from the previous owner or something else but we wheeled the same thing then I took all the optional lines and had no issues...Age or neglect?

So we called Zach and Oakland t case express and going with Zach seems to be a better deal due to warranty on the case and he can keep the old one vs. sending in his broken one as a core so he can fix it and have it ready for next time

I found my t-case on the web through an auto-wrecking listing. I paid $1100 for a low-mile, rebuilt out of S.Cal... it's not easy to find a 4:1 case...
with that said, you can buy parts for the transfer case... for me, it was 600 or so in parts plus labor - or the guaranteed one

I'll be interested to see who you use to fix you case. I'm sorely tempted to have my broken one fixed so I have a backup... really, just need 2 gears, the shift fork and a chain. My goal is to also have a transmission on my shelf as well for when (not if) it goes.
 
Last edited:

Zach

Mall Crawler
Messages
4,812
Location
So Cal
I found my t-case on the web through an auto-wrecking listing. I paid $1100 for a low-mile, rebuilt out of S.Cal... it's not easy to find a 4:1 case...
with that said, you can buy parts for the transfer case... for me, it was 600 or so in parts plus labor - or the guaranteed one

I'll be interested to see who you use to fix you case. I'm sorely tempted to have my broken one fixed so I have a backup... really, just need 2 gears, the shift fork and a chain. My goal is to also have a transmission on my shelf as well for when (not if) it goes.

You would really be surprised at what a new t case is
 

06 H3

a.k.a. "The Jackal"
Messages
9,506
Location
Meridian, ID
that is fine but someone else can help answer the question I have. Is it true that once a t case or diff is damaged the casing has taken some abuse and the likely hood of future repair is greater?

Or do you fix it and your good to go with no concerns of it breaking.
 

SuperBuickGuy

Well-Known Member
Messages
3,403
Location
Woodinville, WA
that is fine but someone else can help answer the question I have. Is it true that once a t case or diff is damaged the casing has taken some abuse and the likely hood of future repair is greater?

Or do you fix it and your good to go with no concerns of it breaking.

impossible to answer without seeing the case. If you take it to a shop to be repaired, they can answer that question.

with that said, if you play percentages; unless there's a big hole in the case, it should be repairable (even is reparable with the big hole, just not financially worth it).
 
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