Hill climbing question

I have a 2011 Husqvarna YTH 2348 with a bit over 1,000 hours on it. I've done a few mods to it; new Briggs 27hp engine @ ~ 350 hours, ag tires on the rear, bearings in the steering, beefed up rear axle mounts and more.

My current problem occurs when climbing hills. There's a 6' to 8' high hill that I mow. It's kind of steep, steep enough that I don't feel comfortable mowing along the hill. Instead I drive up, then back down, move over and repeat. I start at the less steep end and work my way towards the steeper portion. At a certain point, if I have the direction control pedal all the way in the forward position the mower will stop moving before it reaches the top of the hill. If I back off slightly on the pedal, the mower will start moving again and continue climbing the hill. As I move along the hill, it'll eventually get to where the hill's too steep to climb - the mower will climb a ways up the hill, then just stop moving, no tire spin, just no movement, no matter what (forward) position the pedal is in.

Neither the ambient temperature or the rear axle temp seem to have anything to do with this problem. It'll happen whether it's 50 degrees or 100 degrees outside and it doesn't matter if I've been mowing all day or just pulled out of the storage area. There's a new drive belt and front pulley on it. The rear axle oil was changed at ~750 hours.

Have you checked the position of the forward/reverse lever on the transaxle?

Dont know your mower however the lever can be adjusted on my mowers, so that the transaxle works correctly in Forward Neutral Revers ie the foot peddle action/movement delivers the expected response from the transaxle.

This may help you

Looks like that mower uses the Tuff-torq K46 tranny which is not known to be the strongest unit But keep in mind that with a hydrostat less pedal is more torque, which would explain the mower starting to move when the petal is slightly released. But also the mower stops moving when the pressure rises above what the pump can product which basically goes into relief mode.

ILENGINE said:

Looks like that mower uses the Tuff-torq K46 tranny which is not known to be the strongest unit But keep in mind that with a hydrostat less pedal is more torque, which would explain the mower starting to move when the petal is slightly released. But also the mower stops moving when the pressure rises above what the pump can product which basically goes into relief mode.

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K46 is not a hill climber. You are slowly killing the transaxle. Not made to consistently be pushing it to do this over and over, week after week.

ILENGINE said:

But keep in mind that with a hydrostat less pedal is more torque, which would explain the mower starting to move when the petal is slightly released. But also the mower stops moving when the pressure rises above what the pump can product which basically goes into relief mode.

Click to expand...

This. The hydrostat pedal is basically a variable gear ratio. Pushing it harder doesn't produce more power. If on flat ground, it will result in more speed, but less torque. Climbing steep hills with a K46, I wouldn't push that pedal more than half way. That will result in less stress on that transmission, and less stress is good when it comes to K46's. The fact that you have 1000 hrs on a K46 is already amazing. You (or someone) has been changing the fluid.

I think you are pushing the design limitations of the transmission and possibly the drive belt is also slipping a little from a weak tension spring.

Yep, this mower's had a hard life. I use it to pull a 6' x 10' flat trailer (loaded with brush & cut trees), pulling a small dump trailer with the same load-out, dump trailer with 15 gallon sprayer, and, of course, mowing. The mowing is done up and downhill and on flat areas. Most of the hard to get to places are done with this mower, the easy areas are done with the Kubota zero turn. There are more elevation changes on this place than it looks like. Nothing more than 10' high, most I don't want to mow lengthwise 'cause of the angle. So it's up and down or diagonal.

I've changed the transmission oil once. Had to pull it at ~750 hours to remove a broken front mounting bolt, figured that was a good time to do the oil change.

BTW, what are y'all using for oil in a K46?

I know it's the weakest trans available, but until it breaks there's work to be done. Might look into swapping in a stronger unit if/when this one buys the farm. I've also got a couple smaller, broken mowers here that I might look to for a trans swap.

I'll take a look at the tension spring - probably end up putting in a new one sooner or later. And I'll try using less forward on the pedal next time.

I use regular Castrol 20W50 engine oil for the hydrostatic transmissions most of the time. Synthetic is overkill for any machine with high hours.

The Hydro Gear manual for my ZT-3400 calls for 20W-50, and an oil change interval of 400 hrs. For a K46, I wouldn't go more than 200 hrs between changes.

You might try Lucas Hydraulic Oil Booster and Stop Leak. It thickens up the oil in the hydro and Lucas recommends a 20% mix. I have use it at 30% with no problems.