Cub Cadet Z Force 44 Briggs 20HP Loses drive power during use

I have a Cub Cadet Z Force 44 Briggs 20HP (53AA5A6L710) that I have resurrected and now use on a weekly basis. I have some steep (20 degree or so) hills that really stress the mower. I start with the front yard (flat) and head to the back. While mowing the back yard, I start to lose drive power on one side (left, I think). If I park and wait about 30-60 minutes, I can finish my mowing with no problem. I have tried splitting the load by doing part of the back first, then mowing the front, and finishing with the back. Same results.

Any ideas? PTO clutch? A drive belt getting hot?

Thoughts?

The left hydros tend to accumulate a lot more dirt than the right so overheat .
This causes the oil to thin & the hydro to loose power on the left side.
So clean the outside .
If the problem persists change the oil and go for a heavier oil.

If you go to the tranny factory web site you will see the parts break downs for your trans
You will see that the valve chest rotates on a plate with slots in it.
The slots allow the oil to enter & exit the pistons.
When the oil gets thin it get lazy and passes between the valve chest & the plate rather than going through the pistons.
So you loose power

bertsmobile1 said:

The left hydros tend to accumulate a lot more dirt than the right so overheat .
This causes the oil to thin & the hydro to loose power on the left side.
So clean the outside .
If the problem persists change the oil and go for a heavier oil.

If you go to the tranny factory web site you will see the parts break downs for your trans
You will see that the valve chest rotates on a plate with slots in it.
The slots allow the oil to enter & exit the pistons.
When the oil gets thin it get lazy and passes between the valve chest & the plate rather than going through the pistons.
So you loose power

Click to expand...

Thanks! I will try that. BTW, what is the tranny website addy?