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dramm

Hydro Output Shaft and Tranny Case Leak on 900/7100

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dramm

Hello,

Between family members we have some various models of the 900/7100 series tractors.  Each has does well at leaving it's mark with various small hydro oil leaks, and on one 912 in particular we've had the seals replaced on the axle shafts, brake shaft, hydro input shaft and opposite the charge pump.  Doing this seemed to fix up that one well.

A few years ago I bought a 7117, and other than running it a few times a year for exercise I didn't do much with it.  A few months ago I decided to clean it up and changed the hydro oil and filter.  I've used it a lot more since then, and it looks like to me there is a good amount of oil showing directly under where the hydro output shaft goes into the transmission case.  It could have been like this before, but it was so dirty that the oil might have been soaked up in all the crud, or I just hadn't run it hard enough yet to show.  If I clean that area up and let it sit while running at low engine speed for a while nothing shows, only seems to be when its at work.

A couple of questions:

1.  Does this area where the output shaft and transmission case meet tend to leak?  I was also wondering if it could be spatter from the nearby hose, but it doesn't look that way to me.  As I type this I don't remember now either if I did a really good job of making sure the relief valve vent moved freely, if that is sticking can it cause the system to over pressure?  Guess what I'm saying is what are the chances I self-induced this rather than it being from that spot not sealing up properly?

2.  Granted the output shaft/tranny case meeting point is leaking, I'm little confused on what gasket or seal might be there when I put it back together.  In reading the service manual I have (repair manual for 7000/7100 series book TP-973, similar to what is in the downloads section here, pg 257 in particular) it says to use gasket eliminator.  Does that mean there is no actual gasket there?  Or is the gasket eliminator only applied to those two cavities?  And then what are the cavities for? 

Sorry for the long winded post, wanted to give as much detail as I could.  I've always been afraid of doing things with the hydro, realizing now I need to get over that fear.

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Brettw

Welcome to the club!  There is a gasket between the two, pump and transaxle, but before you go through all of the work to tear it down and replace that, check the seal at the pintle shaft where it goes into the pump.  This is the input where the cam adjusts the forward and reverse motion of the pump, on the "front" of the pump (towards the front of the tractor).  I thought I had a leak at between the two parts too, but it is actually leaking out of the seal at the location I describe.  So I would give that a good look first.  The hard part about removing the pump to service or replace the gasket you speak of, is removing the driven pulley on the pump, without damaging it.  They can be a real bear to get off.

 

Good luck, and, welcome again!  

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dramm

Thanks!  I appreciate the welcome.

I went out and looked and I see where a leak from the spot you mentioned could find its way down there.  I'll give it another run and see what I can find.

Thanks Again!

 

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Bill725

FYI, the Sovereign IPL states the following in the footnotes of the Transmission Group page:

A) (Pointing to the gear case assy.) Mask hydrostatic mounting surface and cover hole prior to painting.

B) (Pointing to the gear case assy.) Use "GASKET ELIMINATOR" and place 1/8" bead all around. Make sure O-ring on pilot bearing stays in place until assy. is complete. After contactis made with gasket material, complete assy. without smearing gasket.

C) (Pointing to the Hydro unit.) Clean mating surface with LocQuic primer NF by spraying & wiping with a clean cloth to remove contamination. If part is assembled within 30 minutes no additional treatment is required. Otherwise spray thin film onto surface. Permit to visibly dry.

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