Cub cadet RZT 50 hydrostatic transmission

[Pegasus1]

I would also like a transmission manual for the RZT50 if anyone has one. It seems I am having simular problems as described here.


Thanks,

RP

I recently purchased a 2006 TroyBilt ZRT50 with 256 hours on it. I know it's not a Cub, but other than the paint and nameplate, it's exactly the same mower. I got it cheap because of the dreaded left hydro syndrome. It displayed all of the classic symptoms... would work for a little while and then lose power. I was prepared to disassemble the unit, or replace it if necessary. After hearing a chirping sound coming from the left side, I discovered that the idle pulley was contacting a bracket in front of the engine shaft. When the belt was cool, there was enough space for the idler to clear the bracket. Once the belt heated up and stretched, there wasn't. I replaced the belt with a new one, the pulley cleared the bracket... but not by much. Wasn't long before it was hitting it again. I figured a larger idler would take up more slack, so I put a 5" on it. After chewing up the belt, I put an old spare belt on (to get by). This lasted only a very short time. I got a new belt, and when I tried to install it, it wouldn't fit. I pulled the idler assembly off and reinstalled the OEM pulley. The belt fit, but I had to use quite a bit of force to seat the spring. Actually, a LOT more force than ever before. That's when I noticed the location of the idle pulley. No longer was it barely 1/4" from the bracket, waiting for the belt to stretch... but was nestled halfway between the engine pulley and hydro pulley. Obviously, all of the belts I had installed were too long, and there were several! I finished reassembly, and fired it up. I cut about an acre, mowed UP some pretty steep hills, and it handled like a brand new mower. No more slowing to a crawl, or stopping, when trying to get up hills. Control is crisp, smooth, and responsive.

This may not be the case for some people, but I definitely recommend that you check your idle pulley location before tearing apart, or replacing the hydro on your mower. If the idler hits something, or even if the idle arm is sticking, you'll lose power to the left side. You must have tension on the belt at all times, and it has to be applied in the proper location to prevent belt flop. I hope this helps!

 

[OldMachinist]

When the RZT first came out there was a grease fitting for the idler pulley pivot. Sometime later they removed it. several users have found that the arm is ether stuck in place or binds before tensioning the belt properly. If you have one that doesn't have a grease fitting you should remove and grease the pivot at least once or twice a season.

 

[Pegasus1]

The arm wasn't binding, but I went ahead and cleaned it up before giving it a good greasing when I replaced the first pulley a few months ago. I know the drive belt isn't installed in the picture above, but even so, the idle pulley on my mower rests in nearly the same position now... instead of almost directly behind the drive pulley. Good point on the grease.

 

[healey2011]

I've been following this thread because I also have the lack of power and noise problem with the left transmission on my 2005, RZT 50, I bought it used with 247 hours on the meter. I changed the oil (it definately had some water in it) and the problem still starts after about 45 minutes. Why is the problem on the left transmission only? Have there been any improvements made to the new replacement transmissions to correct this problem?

 

[TRWILL]

I've been following this thread because I also have the lack of power and noise problem with the left transmission on my 2005, RZT 50, I bought it used with 247 hours on the meter. I changed the oil (it definately had some water in it) and the problem still starts after about 45 minutes. Why is the problem on the left transmission only? Have there been any improvements made to the new replacement transmissions to correct this problem?

It sounds like to me that you need a new drive belt. I find that the original belts from CUB don't measure up. A better belt is by MTD. the number is 954-04043A. It takes a lot of power to run these hydraulic drives and the use of A belts won't take it if you stress them to hard. I think the reason that the left side gives problems first is the design of the tentioner arm. The bell crank has a ratio of at least 3 to 1 in favor of the pully. when the belt wears or if it starts slipping for any reason it don't take long to over heat and wear down quickly because of the power involved.
If your problem starts after about 45 minutes of use that indicates to me that you have a worn out drive belt. It's good that you got the water out but before you consider problems in the drive again put on a good drive belt and make sure the tentioner spring has plenty of pull. Replace it if you suspect it to be weak. Compare the drive belt tention with that of the deck belt. It may be a little less because of the bellcrank ratio I mentioned . I hope this helps. TRWILL

 

[healey2011]

I've just ordered a belt, idler pulley and tension spring, along with some other small parts that need replacing. I'll post an update after I install them.

 

[Pauli Gonzali]

I am getting the FITS from my cub zforce 50 as well. My left side was weak so I figured it was the transmission. Took it off and to my surprise the oil was actually in awesome condition. I stuck a straw in their to pull some out and it still looked like it had plenty of life. The mower only has 87 hours on it. This has really ticked me off. Put a new belt on today (cub dealer belt) and it didn't help at all. Now I got a noise from the left tranny.
Think I need to do idler pully & tensioner combo??

 

[rmarkw]

Pauli, noise from the left might be air trapped in the tranny. Have you tried the purge procedure? My left tranny went out and I got it going by changing the oil. The following year my right went out. A change of fluid and new belt didn't help, so I had to put on a new one.
I might crack the old one open one day. Has anyone opened up their transaxle to see what is tearing up inside them? I'd bet it's the filter on the bottom of the pump.

 

[mobigfoot]

I am trying to order a new left hydro and the vendor wanted me to pull the left hub to verify if it had a spine or double d axle. I can't get the left rear hub off to check I have tried beating, heating etc and it does not budge. Can anyone tell me how to remove the hub from the axle?

 

[Pauli Gonzali]

How did your mower turn out?