Hydro shudder/chatter
 

Just changed out the whole rear end and hydro pump on my 1250. The reason for the change was my hydro pump was leaking from the hydro pump housing itself where the 2 halves go together. Thought it would be easier to change out the whole business. Don't have any experience since it came from my 1450 parts tractor that I have driven very little.
Everything went well in the change and even put on a new cub filter, new trunion springs and lubed up the hydro plates for hopefully a smooth drive. This one seems very strong in the drive department, it's not a lazy hydro pump. Used it today for the first time to mow an acre and a half and it seems to shudder or chatter a little bit going up the slight grade in the yard. Does go away if I change to a faster speed. Seems like it my be slipping a little. I find it hard to believe as robust as it seems to be. Noticed it more when it got warmed up. The hydro fluid I did not change, just topped off with generic brand fluid. The color of the fluid was kind of yellow/green not clear. What do I do to remedy this? Change the fluid? Switch over my valves? Or change to another pump?

I'd swap the relief valves. Good chance that's the issue.

That would be an easy fix. My valves are near new in the old pump. I'll give it a try. Any other input would be great

I'd also change the fluid. That may help also.

My humble 1/50th of $1.....

Change the relief valves and drain old fluid, put in new Hy-Tran.

Sorry for the delay in getting back to this thread. First time I have had to work on the tractor. Switched the relief valves over from my old pump to this one and mowed the grass again. My observations are that when it is cold for the first 5 to 10 minutes of mowing everything is fine then as it warms up, it starts to do the chatter thing. It only does it at one speed going up a slight incline. If I give it more or less ground speed it goes away. Next thing is changing the fluid I guess. Anymore thoughts?

Not until the fluid is changed. Make sure you use the correct filter. :beerchug:

I agree with everyone esle. change the relief valves, and change the fluid and Filter, using the correct hydraulic filter. Use Hytran..it works!

When you say the oil is a greenish color and that makes me think its quick lift hyd oil the oil that is made by the devil. We just had a sprayer come into the shop that would not maintain speed. And would be jumpy. We found it had quick lift oil in it. We flushed about 20 gals of oil through it and filled it with the proper oil and now it works fine. You can use what ever oil you want but I would not use quick lift oil.

Ahh. I hope that is it. I have some Farm & Fleet generic oil made for Case/IH that I have used before with success in the garage that I am thinking of using. The question is how thorough do I have to be in getting all that stuff out of there? I don't have another rear cover gasket on hand. Was thinking of taking the fill plug out and using a suction siphon to set the fluid out while lifting the front of the tractor up in the air. When the rear was installed last week, I did put a new Cub brand filter on it at the same time. Was not going to change it again yet. Do you think that would be adequate doing it this way? Thanks for all your help!! There is a lot of experience here on the forum to keep these alive

I would remove the rear cover. To be honest I stopped using gaskets on the cover. I not use ultra grey sealant on them. It is the same stuff cummins uses on there engines because they don't have gaskets on some parts. As long as the surface is clean and dry it works fine. The only problem I have had is sometimes it leaks when you put a tiller gearbox on. Check for metal when you drain the oil.

:Morning: You can buy gasket material at NAPA, and make your own. I too would pull the cover. After draining, raise the front of the tractor and flush out any residue with brake clean. Then refill with IHC Hi-tran, should be 7 qts. As far as the filter, I would change it too. :American Flag 1:

To answer the question, it's VERY important to get all of that garbage out of there. No sense doing 1/2 the job and wasting your money. Personally, I'd put another new filter on it too.

That's exactly what I do but I'm too lazy to lift the tractor in the air and just use my fluid gun to suck out as much as possible and then finish with a rag. I use the fluid gun to fill it too so it's already out and going to be dirty anyhow. :)

I'm also too lazy to make gaskets unless I have to so I buy them from Cub. There's nothing wrong with sealant as a gasket, I just personally don't like doing it (personal preference). The next one I do I'm going to do like a valve cover gasket (hi-tack one side of the gasket and glue it to the cover, then grease the other side before installing) and see if I can get away with reusing it a few times. :bigthink:

Go buy some permatex ultra black, it is without a doubt the best silicone on the market but don't use to much or you'll have to destroy the cover to get it off next time.

:Morning: I have a chain fall in my shop, so no problem lifting anything. Maxwelhse, what CC dealer do you use around the Fort? The old grease trick, learned that many moons ago from my Father and Grandfather. I also use red hi-tack on some gaskets. If I hi-jacked this thread I apologize. :American Flag 1:

:Morning: I have a Buddy that use the ultra black. He has the mind set that more is good, therefore he wastes most of it and usually has it over all his hands and what ever he is trying to seal. Its a wonder with all these new sealers in recent years, how we ever got by with number 1/2 permatex back in the day? :American Flag 1:

#2 permatex is still my favorite, thin film of it does the job.

That's why I don't like it.. Few people do it right and I've had to clean up too many messes made from it. When I see RTV on a part I immediately dread taking it off (which can be a nightmare) and then finding whats under it.

Myself and other know how to use it correctly, but it just makes me sad... So I don't do it. :)

I prefer to use bubble wrap. I like the sound it makes when you tighten the cover bolts up. it usually leaks but I still have fun every time I reseal one. and once in a while it works. so a good time is had by all

That's the best! LMAO. :biggrin2: Wonder if you could use bubble wrap instead of plastigage when you check a rod for clearance? The more pop's the tighter it is?

OMG!! LMAO! :ExtremeFunny::ExtremeFunny::High5:

gotta throw that stuff in their once in a while .

good one on the plastigage Sam.

LOL guys! :biggrin2:

finally got a chance to work on the Cub again. All went well this time. Took the back cover off the rear end and drained all the old fluid out and cleaned up the sludge on the top part of the housing with brake clean and heavy scott towels. This is the first rear that I have had that sludge in. Changed out the hydro filter with a new Cub one that is white not yellow. All the ones I have had have been yellow. Guess they made a change recently.
When I installed the back cover I have always had problems with the gasket seeping fluid on many occasions. This time, I put a thin layer of black RTV on it and let it set up for a week before I filled the rear with Hytran. Hopefully no leaks!! This was the moment of truth when I fired it up to mow. All is good-no chattering. I assume the new Hytran was the trick. Thanks for all your guys input. What a huge help. Surely thought I was replacing the pump with another one!!

Great news!:beerchug:

Glad to hear it!

Speaking of sludge, when I went thru my trans axle the axle housings were full of crap also. Bearings were good ,so new seals, gaskets , and hy-tran was all it needed.

Chris