[Calvin Smith]

When the blade is up and I continue to pull back on the lever to try raise it more it make the tractor move fast for a little bit then it slows back down as if it puts more pressure on the pump that it has lost I don't know it has 3450 hours on it so that was my first guess

 

[stevev]

Is the hydro fluid level correct?

 

[Calvin Smith]

Yes and a question on that mine goes down really slow but in my 318 it sucks it right down

 

[michaelm]

When the blade is up and I continue to pull back on the lever to try raise it more it make the tractor move fast for a little bit then it slows back down

Is the tractor moving slow/sluggish in general, or you just noticed a slight speed change when you hold the lever? You don't say if you're actually having a problem with the transmission.
My 420 speeds up a little if I raise the rockshaft (mower deck or 3 point hitch) and hold the lever. Everything seems fine otherwise. It drives just fine and has good power. I don't worry about it.

 

[knottyrope]

seen this being normal over the years unless you are going too fast or lose steering from it

 

[Calvin Smith]

When I hold the lever it picks up a lot of speed and it will only do it when I'm on a flat or down hill surface not pushing snow otherwise when it's going slower it isn't even as fast as my 318 so somethings up

 

[dhager4692]

What year is this tractor? The early ones had four port steering and there were similar issues.

Another thing I would check is the hydro linkage as it can cause the issue of speeding up on a decline. That is a problem I need to fix on mine.

 

[tmac58star]

Time to pull the fender pan and eyeball the hydro linkage for slop/wear.

 

[Calvin Smith]

It's a 1985 I'd have the fender pan off but I don't want to take the cab off since its to cold to not have one

 

[michaelm]

I had one of the bushings in the hydro linkage wear so much that it would speed up going down hill and slow way down going up hill. Just replacing the one bushing made a huge difference. It's not perfect, but it holds it's speed now. You can check this without removing the fender pan just to see if the problem is there. From the rear, reach in and see if you can move the lever on the hydro. If you can move it much at all you have an issue somewhere in the linkage. At least you'd know what the issue was and could decide if you want to wait until spring to deal with it.

 

[Calvin Smith]

Thanks going to the garage to look right now

 

[Calvin Smith]

Ok that is the problem but I still want to know why the hydro fluid takes so long to fill and if it would bad to fill with hydraulic fluid it takes about 5 minutes for a small funul worth of fluid to go into the transmission

 

[TempletonJDguy]

Yes it will go faster if you remove the top end of the sight tube hose that goes into transmission. No you can’t use hydro fluid. JD low vis hy gaurd only or type f atf (if you see it’s red and think it’s atf). It will go faster if you pull the fender pan and add directly from top where fill tube hose goes in.

 

[charms]

In the picture posted earlier, the oil fill tube connects to the white plastic elbow in the left side of the picture. There is supposed to be a vent hole in this fitting, but it can get plugged. I think it is on one of the hex wrench flats.

 

[michaelm]

Could the fill hose be kinked somewhere on the way back to the transmission?

 

[charms]

Could the fill hose be kinked somewhere on the way back to the transmission?

I suppose that is possible, but I've never encountered that.

 

[TempletonJDguy]

Could the fill hose be kinked somewhere on the way back to the transmission?

There’s just so many bends in it it’s easy to get flattened in spots. Not ideal design but we’ve all dealt with it. For me pulling the fender is a 5 minute job and the easiest way to get to it.

 

[Calvin Smith]

I will look at the 90 on the trans where it gets filled first since that's easy but since there is a cab on there I will have to wait until summer to check out the fill hose

 

[neil]

I'll be doing this job in summer too Calvin because I also have the winter cab on. My hydro control linkage is worn too