The first two two things that come to mind are:

1) Are all of the tensioning devices on the belt in proper order and is the belt routed correctly. Going uphill forwards at a faster speed would load the system more.
2) Are you maintaining traction? A wheel losing traction but not "spinning" could feel like something grabbing.


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Checked drive belt and all pulleys and tensioners. All looked goods. Plenty of tension on drive belt and it is routed properly according to instructions. Also I put new axle square keys for rear wheels. Wheels not slipping or spinning going up driveway. Traction good. Decided maybe I didn't purge enough.

I purged with tranny disengaged and tractor on jack stands, 8 to 10 seconds in forward and reverse about ten times. Then engaged, forward 8 to 10 seconds, then reverse for 8 to 10 seconds about ten times. Repeated the whole process, disengaged then engaged, all at a slow to moderate engine speed. Then removed jacks and tried outside. Again, on level ground, beautiful. Reverse up, hill, beautiful. Forward up hill, same problem. Something grabs and then releases. This time, I removed the disconnect linkage rod, to be sure the disconnect lever has no pressure on is in the relaxed position (engaged). Same exact results. The two things I wonder about are the Break Return Spring and the Hydro Link. Could either of these cause this problem ? Maybe the spring has lost some of it's tension or maybe something in the hydro linkage needs to be adjusted ? It only happens on an upgrade. On the Jack stands, it worked great. Should I add more oil to Pump and Motor Module? It calls for 1.25 to 2.00 inches of oil when measured from the inside bottom of the module. I had checked it when I received the transaxle, and it measured about 1.75 inches. Could the slope of the hill cause the oil to loose pumping for a second ? I'm grabbing at straws, but if I can back up the hill fast backwards with no problem and go forwards and backwards on level ground with no problems, and work perfect on the jack stands, what is happening in the transaxle, differently, going up a hill in forward?

Any thoughts? Thanks for any help you can give me. This replacement tranny (799031) seems great, very powerful, but something about going uphill in forward, just isn't right.

 

The first thing to comes to my mind is that a lawn tractor transmission has no business being on a slope as steep as 22°.

Methinks that you have found the straw. The slope causes the fluid to move to the back of the case, possibly uncovering the pickup for the hydro in the process. These little hydros aren't designed for steep slopes and may be built accordingly.

 

Thanks for your reply. I think I'm going to drop the tranny and check the oil level. It may be a bit low. If so I will add oil, purge and try again. That seems to be the only thing that makes sense. Possibly, going up hill backwards doesn't uncover the pickup tube, but going up hill forwards, maybe it does. Thanks, again

 

Low oil, not the answer. Same problem, but, just learned today, I am not the only one having this problem. Everything works on level ground and backing up a hill with out any problems. But, going forwards up a hill, you get a clicking sound and pulsing of the tractor. Well Tecumseh/peerless, just happens to have a non advertised repair kit for the LTH 2000 series Hydrostatic trans axle. it is part number 799032. Mind you the transaxle kit to go from a VST to a LTH is part 799031 ands repair kit 799032 !!!:tango_face_sad: This kit is a neutral lock out repair kit, part# 799032 and goes in the Differential section, not the pump/motor module. Well I got it from sears, where I got the trans axle from. No warrantee !!!! I had hoped I wouldn't have to pay for the kit, since I just bought the trans axle and immediately had problems. Oh well, it just costs $42.68 and with a discount coupon I got $6.36 off. So with tax and shipping I paid $47.63. If it solves the problem, I will be ecstatic. I will post how it works for me when I get the kit installed.