Hydro-gear transmission for mower.

Turkeyfoot

Well-known Member
I don't have very much experience with these lawn mower transmissions. So I'm looking for help advice etc. I posted this in tractor tales but thought I'd try here too.

Looks like I messed up. A few months ago I posted about having a stick knock the drive belt off my Cub cadet mower and also break the cooling fan that sits on top of the transmission. Completely destroyed the plastic fan. At the time I didn't think too much about the ruined fan. That looks like my mistake. I got the belt back and all seemed normal. I used it to haul around firewood during the winter. Then on Saturday I fired it up to mow and after about 45 minutes the transmission started stalling and rattling. Now it sort of works but the transmission is loud and doesn't reach full speed of have full power and it bucks and stops when going in reverse. So I figured the transmission is shot since the belt and linkage seem fine. Looked around online to get a new transmission and it seems this part is no longer in stock. I checked the two main online vendors I could find they replied right away that this is no longer manufactured. Since it's the only mower I have that can get up under trees and stuff like that, I need to replace it. Or find a replacement or rebuild kit for this transmission. The transmission is hydro-gear 618-04270B. The mower only has about 550 hours on it and otherwise runs great. Any thoughts on rebuild or source for used transmission or substitute.
cvphoto124550.jpg
 
Yes. I called them but the person I talked with wasn't much help. I just tried an email maybe I'll get a better reply that way
 
I would think parts for your transmission are available for your transmission through Hydrogear.

from your description, it sounds to me like the thrust bearing has failed in your pump. I am not familiar with your particular transmission, but in the ones I have been into, when the thrust bearing comes apart the bearing balls beat up the piston group/rotor pretty badly too, and in some cases metal tries to go between the piston group/rotor and damages the 'center section' as well.

There are some videos on Youtube if you want to attempt repair. Parts are going to be probably half or more of the cost of another transmission if you can find it.

Another option is to find a working transmission. But there is some risk there, it may fail soon too.

P.S. I am thinking the fan is a Cub Cadet part, not a Hydrogear fan. At least the Cub Cadet I worked on last week was.
 
Any chance you can find a similar Cub Cadet with a blown engine cheap? If it was a Sundstrand hydro from ANY IH hydrostatic Cub Cadet built since 1966, they ALL interchange.
 
Thanks for the replies guys. I pulled it out yesterday and I'm going to take it to a place tomorrow to see if they have a match. It will be a used one. That's going to be my first try. If no luck there then I'll probably try to find one like Dr. Evil said. Or try to do a rebuild if I can get the parts.

cvphoto124668.jpg
 
In the photo I posted you can see the fan is missing. I think that's what damaged it. I also wonder if it's just out of fluid because there was some sign of leaking on one side. Not an active drip but just some oily build up. I wanted to check the fluid level but I couldn't even get the plug out of the filler hole. It has a hex type cap screw and I stripped the hex. Before I took the tranny out I did try to purge the system of air using the instructions from hydro gear. that didn't help. My thought was that it overheated and oil went in the reservoir and then some air was introduced when the oil got sucked back into the transmission.
 
Those plugs can be really tight. From experience, if you strip out the allen socket, you can (sometimes) grab the outside with vice grips and try to turn it while a helper taps on it with a hammer and punch.
You can also (sometimes) get them to turn if you can get a cold chisel to bite in the outer diameter and drive it in the 'off' direction.

I am thinking your oil level shoud be withing 1 of the top where the plug is. 20w50 motor oil will work.
 
I was able to get the plug out this morning. Oil level was right to the top but man it was blacker than coffee! Going this morning to see about buying a used one but I might try changing this oil and finding a replacement fan. Do you think it's possible that without the fan it just super overheated and turned the oil black and that is the problem, the oil broke down? When it went out it was the first time I'd run it for a prolonged period since the fan sheared off last winter.
 

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