Cub Cadet RZT50 - Hydrogear

[kasedian]

Ive got a good one for you guys. I have a RZT50. Had it for about 5 years now, with 250 hours. After the first year I had it, the left side transmission went out. Had it replaced under warranty. Well, anyways, I got to looking at it a year later, and the hydrostat that they put in was a little different than the other one. The only thing I noticed, was that the replaced one had a vent tube coming out of the top, down the side oabout 6 inches. The original side hydro has a hose going up under the seat to a fluid resevoir. Well, I retrofitted the fitting, got rid of the vent tube, and ran it up to the resevoir.
I dont know about your machines, but do most of them have these fluid resevoirs? I see warnings not to power wash them, and was wondering if that only pertained to the ones with vents. Thanks

 

[JTKub]

I believe some of the Hydro-Gear EZT drive equipped machines have a common bottle, with both drives plumbed to it. Others are just vented like your 'new' drive. The main thing is the drive is vented properly so condensation can't build-up in it. If you bump-up a model to the ZT-2800 drives or above, they all share a common bottle. I know on mine, it looks empty when the machine is cold and fills up about a 1/4 of the way when hot.

Joel

 

[LeftTurn]

I had to replace both transmissions last year on a 3 year-old RZT50.

The dealer disconnected the oil reservoir (under the seat), telling me that the new transmissions "are sealed". I sure hope that he's right!

 

[kasedian]

Hmmmm. I took the breather tube fitting out of the top of the transmission, and replaced it with a fitting that attached to the hose that went to the resevoir. I dont know what it will hurt doing that, but so far it seems to be running fine. Ill take pictures later this week when it stops raining and post.
Anyone else see a problem with retro-fitting a "sealed" transmission with a breather, to one that connects to a resevoir?

 

[JTKub]

It will still "breathe". That's the main thing. I'm thinking they might have left it segregated so there could be no cross-contamination with the other drive. Just a guess.

I like the idea of having the breathers run to a bottle. That way you could atleast get sort of a visual idea if you've got moisture in the oil or whatnot. They say not to add oil to the bottle because it's only meant as an expansion tank, but a little 15w40 in there won't hurt. Like I say, it stays empty on my ZT-2800 equipped Z-Force, but fills up 1/4way when hot.

Joel

 

[LeftTurn]

My only concern is how long the things will last. I got just over 200 hours on the first set of transmissions. At a $1500 to replace both, I feel like I "rented" them for about $7 per hour!

 

[JTKub]

My only concern is how long the things will last. I got just over 200 hours on the first set of transmissions. At a $1500 to replace both, I feel like I "rented" them for about $7 per hour!

I feel for you. I don't know that we've ever come to a conclusion as to why the failures occur other than;

1) Some had severe condensation contamination of the oil. Suspected cause was water wicking it's way down the input shaft and into the case, in conjunction w/ poor case venting. Supposedly a better shaft seal was designed, but I'd do all I could to keep the mechanicals dry on these machines. Any sign of weakness from a drive and immediately pull it and do an oil change.

2) Something along the lines of internal thrust washer failure, or something rubbing/wearing into the case causing excessive heat and failure. I have read of 1-2x where owners tore into it and fixed this themselves.

Why it's the left drive that primarily fails is a mystery to me. Their both identical aside from layout.

Joel

 

[LeftTurn]

I've wondered about that deck wash system, where you are supposed to hook up a garden hose to the port on the deck. It seems like spraying that much water on the underside could cause some to get into the transmissions. I don't use that anymore, but I did a few times prior to the transmission failures.

 

[wdchyd]

I've seen these hydrogear hydrostats fail at the main bearing/swash plate assy on the rotating group internally.......IMHO these units are being pushed to their max limit as far as durability.......the oil reservoirs are way undersized and they run way too hot for my comfort......if you have a failure on one side then take off corresponding wheel motor, open up, clean, reseal to remove contaminates internally......if you don't rinse out the wheel motor you risk the likely chance of repeated failures on the same side....

The only thing I can suggest is double up on your oil/filter changes and if the oil looks dark, do double flushes and be proactive with oil cleanliness BEFORE they get damaged from heat and wear.....

 

[JTKub]

The only thing I can suggest is double up on your oil/filter changes and if the oil looks dark, do double flushes and be proactive with oil cleanliness BEFORE they get damaged from heat and wear.....

Problem is, on the Hydro-Gear EZT series, the only way to drain the units or even look at the oil is to remove them from the machine and invert them, plus there's no replaceable filter.