Topic: T-Case 4.7 install-RUST PITTING on Front Output Gear Question

[Yopar]

Hi. Working on a new Marlin 4.7 gears install, and doing the dual case adapter at the same time.

First, tackling the 4.7 into the rear case, everything is back together and the job came out great. The case is on the floor all closed up, and am ready to get to the crawl box build. Everything feels smooth, operates perfect. But now I am thinking about something. While doing the 4.7 install, I found some pitting on the original Front Output Gear. Here you can see some pics of it.







So, I took the Front Output Gear out of my donor case (the one I'm using the crawl box for) and used it instead, because the gear looked perfect.

Now I am second guessing something... My question is, should I have also swapped the Front Drive Idler gear and the Front Transfer Drive gear, so all the original teeth patterns matched?     I don't think I need any of those for the crawler case anyway.

I hate to tear the rear covers off again, since it's all sealed up, but I will if you guys think I should.

[79coyotefrg]

yea dont use that,  i'd really recommend putting the gears from your other case in there.

[Yopar [OP]]

Thanks. The gear shown in the pic isn't being used, I took the nicer one from my donor case.

My question is, should I have swapped the addtl. gears from the donor case, the ones that mesh w/ the front output gear (Front Drive Idler gear & Front Transfer Drive gear )? Or does this matter?

thanks

[elmo83]

I would put the doner case gears in, all of them plus really give the torrington bearing on the backside of the pitted output gear a real close look. If worse comes to worse change the back cover from the donor case also. The pitting looks like it came from water contamination and if so the bearings got the same treatment so do it now instead of on the trail...

[Yopar [OP]]

Yeah good point, I checked the bearing on the donor gear and it was in fine condition. You're right, there was probably moisture in there, and it looks like the 4wd wasn't used for a long time, so the front output gear sat in one spot, getting rusted.

I'm going to pull the case apart again, get new gaskets and install the 3 matched gears from the donor case. I don't like having doubts when running something.

[Yopar [OP]]

Ok here's what I got happening. Rust and gears, trying to figure out what to run. I pulled the fresh case apart to run the matched set of gears, instead of mixing them.

Here's the 3 gears I'm looking at in the fresh case I just took back apart:


The far right (front output gear) was the worst one, as seen in the original post. The screwdriver is pointing to the original gear. The one you see in the fresh case is the nice one from the donor case.


But now I see the other 2 gears from the donor case, have some rust pitting as well! As seen here in these pics:




So, the gears that are currently installed in the case right now are the nicest ones of them all. The only change made was swapping the Front Output Gear.

I don't have a matched set of gears where all 3 aren't pitted. Either run it as they are already installed with the different Front Output Gear, or put in the 2 other gears that have rust on them and make them match. I'm inclined to run like it is, but am just curious to what's more important; having nice clean gears as possible, or keeping them matched.

[zippo]

If it was me, I would polish it as best as possible. and use it as a spare? I don't think a little pitting would destroy the strengh of the gear, but might make it wear poorly as it is rough.

WD40 is your friend.

[Yopar [OP]]

If it was me, I would polish it as best as possible. and use it as a spare? I don't think a little pitting would destroy the strengh of the gear, but might make it wear poorly as it is rough.

WD40 is your friend.

Yes, good idea, thanks. 


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