Opened Up the Transfer Case..

[Sy229]

that I got from Gary S. This one has an unknown history so we weren't sure what to expect inside. This was also the first time any of us have been inside a TC, so it was both a learning and a discovery expedition:

First up we counted up the number of spines (32) and figured that this was a Typhoon TC.

Other than a little surface rust from sitting around, most of the assemblies looked to be in good condition. The first thing we noticed was a loose pin on one of the planetary gears - it appears to have been sheared off and would likely be a driveability problem.

The second issue was the chain, which seemed to have a lot of play in it. None of the links looked damaged, so we're not sure if its in normal range or not.

George B., do you sell the planetaries? All: Any thoughts on what is an acceptable amount of travel for the chain? Is there any way to tell if the VC is working ok?

 

[Trapper]

Re: Opened Up the Transfer Case..

I hope someone has some insight on this. Im inerested on what you find out.

 

[George Blake]

Re: Opened Up the Transfer Case..

That planetary is toast.
$218 for a new planetary.
The chain is hard to tell. What happens is when you put the cover on, it pulls the chain tight.
If the unit has more than 60K on it, replace the chain.
$110 for the chain.
Check the bearings.
Hold the bearing inner race with your thumb and pointer finger. Spin the bearing outer race with the other hand. You should have a smooth "ssssssssssssss" with NO vibration. Any vibration or gravel sound, replace the bearings.
Bearing and seal kit with thrust washers and top hat front bushing: $120.
Bearing and seal kit without thrust washers or front bushing $80.
The viscous is expensive. If it doesn't look blued or burnt or hasn't leaked out(the little check balls blown out), then reuse it.
There is NO way to bench test it.
If you want a new viscous coupler: $379.00

Guys, I'm working with the machinist that did our input shafts and I'm trying to get him to do a planetary for us. 5 pinion 4340 housing with 9310 gears that run on needle bearings. The current setup has NO hardened bearings and just wears the pinion shaft out and they fall apart.

When you go through that case, make CERTAIN you clean out the hole in the output shaft that feeds fluid forward to the input shaft. See the ice cream scoop on the output shaft? If the fluid level gets low or the hole gets plugged, no lube to the planetary and it falls apart. Take the outer geared race that the planet rides in off of the output shaft and clean that sucker out. Every single groove will be full of powdered metal from the planet wearing out.

 

[Sy229]

Re: Opened Up the Transfer Case..

Excellent inputs George, thanks. I'll go back and check the bearings to see how they're rolling, and chase the lubricating shaft to make sure its clear. I don't know how many miles on this unit so I guess the chain is a crap shoot. Good news with the VC though - no evidence of it overheating so maybe its ok.

 

[SYO237]

Re: Opened Up the Transfer Case..

It was pretty cool taking that thing apart, first time I had ever done it. Amazing how simple it really is and not some voodoo like I thought. It was fully disassembled in minutes.

When we were pulling the planetary off, the pin and gear just slipped right out... took a closer look and saw where the pin was sheared. It is common to see this type of failure in these things?

 

[Trapper]

Re: Opened Up the Transfer Case..

It was pretty cool taking that thing apart, first time I had ever done it. Amazing how simple it really is and not some voodoo like I thought. It was fully disassembled in minutes.

When we were pulling the planetary off, the pin and gear just slipped right out... took a closer look and saw where the pin was sheared. It is common to see this type of failure in these things?

Like a mini PTO box but those require some heat to fully disasemble.

 

[George Blake]

Re: Opened Up the Transfer Case..

Yes. That's another reason why I want to redo the planetary altogether and improve the design. Unfortunately, I don't know how many I would be able to sell because most guys don't do what you did. They just have mysterious vibrations and never think to take the transfer case apart to find the planetary messed up. There are NO needle bearings on that arrangement like a traditional planetary would have and that is the result. Couple that with a "square" housing instead of a round housing and you end up with cracked planets. If you need any of those components please let me know.

 

[TYTILIDIE]

Re: Opened Up the Transfer Case..

They just have mysterious vibrations and never think to take the transfer case apart to find the planetary messed up.

X2, I had the whole wash board vibration in my truck for about a year but it was only on the highway where I did not go very often at the time. It wasn't until my chain started jumping that I decided to take the case apart. Found a very bad planet and the piece it sits in was CAKED with debris from it. When I went to buy a new planet I got the same price you just posted, about $200. At the time I didn't have the money for it so I got a used one for nothing at the junk yard. Had to replace a year later, so I would definitely get the planet. Its amazing what a difference that thing can make in the way the trucks feel on the highway.

 

[George Blake]

Re: Opened Up the Transfer Case..

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