4speedfunk
Well-Known Member
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I got another cool mod I wanted to share with fellow H4Or's.
Like many of you, I had a t-case failure (42,000 miles) and like so many other parts on the H3...I am starting to see a "pattern" of failures. There are certain parts on the H3 fail in a predictable and repeatable manner, and you don't really notice them individually...unless you work on a bunch of them. I work on a bunch of them!...and my latest discovery has to do with the H3 transfer case. Many of us complain about "chain slap", and we typically replace a stretched chain with a new one, and we're good for another (pray) 30,000 miles or so. But some of us have other issues, and I want to talk about a part inside the BW3393/3394 called the "snubber".
This part is a small rectangular aluminum platform with a nylon rub pad bonded to it. It is supposed to quench the chain slap that occurs when you get on & off the throttle. It gets bolted to the inside of the case via two horrendously under-sized bolts. I've noticed that when I disassemble a t-case...the snubber is loose inside the case and flopping around everywhere...destroying the internal parts. Here's the one out of mine (left) and the identical part out of 08H3's (right)...
The big question I have is: HOW ARE THESE GETTING LOOSE INSIDE THE T-CASE? Well, the answer has to do with the small M6 fasteners that thread into two bosses inside the housing. On both occasions, the screws had pulled out of the threaded holes which releases the snubber into the whirling chaos inside the t-case. There are two small towers that the snubber bolts to, and the holes are often stripped. Once the snubber is loose, it gets munched up by the other parts...its soft aluminum, so there is usually no other damage. The loose snubber often gets sucked into the sprocket/chain assembly, and this immediately stretches the chain in a split second. So...my theory is that sometimes, a loose snubber is what stretches the chain. To combat this, I drill & tap the towers and install much larger 1/4"-20 studs into them. Then I attach a new snubber with larger 1/4"-20 nylon lock-nuts.
I start by drilling the original holes with a .201" bit. Then I begin tapping with a standard tapered cut (makes a better cut). Once I hit the bottom, I switch to a bottoming tap and this cleans up the threads and makes them good & tight all the way down. Then I install some grade-8 1/4"-20 studs with high-temp loc-tite. Use set screws if you can find em. If not, just use standard bolts and run em in tight, then cut-off the excess after you're done...
Obviously, you want to protect the bearings while doing all this, and blow out all the metal shavings with compressed air when you get done. I'm limited to ten pics, so check part two for the continuation.
Like many of you, I had a t-case failure (42,000 miles) and like so many other parts on the H3...I am starting to see a "pattern" of failures. There are certain parts on the H3 fail in a predictable and repeatable manner, and you don't really notice them individually...unless you work on a bunch of them. I work on a bunch of them!...and my latest discovery has to do with the H3 transfer case. Many of us complain about "chain slap", and we typically replace a stretched chain with a new one, and we're good for another (pray) 30,000 miles or so. But some of us have other issues, and I want to talk about a part inside the BW3393/3394 called the "snubber".
This part is a small rectangular aluminum platform with a nylon rub pad bonded to it. It is supposed to quench the chain slap that occurs when you get on & off the throttle. It gets bolted to the inside of the case via two horrendously under-sized bolts. I've noticed that when I disassemble a t-case...the snubber is loose inside the case and flopping around everywhere...destroying the internal parts. Here's the one out of mine (left) and the identical part out of 08H3's (right)...
The big question I have is: HOW ARE THESE GETTING LOOSE INSIDE THE T-CASE? Well, the answer has to do with the small M6 fasteners that thread into two bosses inside the housing. On both occasions, the screws had pulled out of the threaded holes which releases the snubber into the whirling chaos inside the t-case. There are two small towers that the snubber bolts to, and the holes are often stripped. Once the snubber is loose, it gets munched up by the other parts...its soft aluminum, so there is usually no other damage. The loose snubber often gets sucked into the sprocket/chain assembly, and this immediately stretches the chain in a split second. So...my theory is that sometimes, a loose snubber is what stretches the chain. To combat this, I drill & tap the towers and install much larger 1/4"-20 studs into them. Then I attach a new snubber with larger 1/4"-20 nylon lock-nuts.
I start by drilling the original holes with a .201" bit. Then I begin tapping with a standard tapered cut (makes a better cut). Once I hit the bottom, I switch to a bottoming tap and this cleans up the threads and makes them good & tight all the way down. Then I install some grade-8 1/4"-20 studs with high-temp loc-tite. Use set screws if you can find em. If not, just use standard bolts and run em in tight, then cut-off the excess after you're done...
Obviously, you want to protect the bearings while doing all this, and blow out all the metal shavings with compressed air when you get done. I'm limited to ten pics, so check part two for the continuation.
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