JD Hydro Won't Reverse

Hand2ThePlow

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I have a JD STX46 with a hydrostat transmission that I bought new in 1994. When I bought it I was told by the dealer that the tranny was a sealed unit and no regular maintenance was needed. The owners manual seemed to confirm this as there was no maintenance schedule or items listed for the tranny.

Reverse only works when I first start the mower, once the tranny warms up it won't reverse. I got on JDParts and discovered that there is in fact an oil fill on top of the transmission but the tranny would have to be pulled to even access it. They also sell transmission filter and vent kits.

My question is: has anyone ever rebuilt one of these trannys, how difficult is it and is it even worth the time and money to do it.
 

44carbine

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I had a STX 38 and I had the same problem as you. Checked on parts to rebuilt and it was not worth the cost. Loaded it up and traded it in on a new deere. Gave me $400.00 for it.
 

FRISKY

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I had similar problems with a hydrostatic unit and found out it was low on fluid. The linkage was also out of adjustment.
 

Hand2ThePlow

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I had similar problems with a hydrostatic unit and found out it was low on fluid. The linkage was also out of adjustment.

That's my thinking right now. Forward speed is slow, maybe 1/2 what it used to be. We did adjust the linkage and I have reverse again when the tranny is cold. To add fluid though requires pulling the tranny which is no small matter. You can't even see the fill on top of the case because of the sheet metal.

Thanks Frisky.
 

GreenWannabe

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That's my thinking right now. Forward speed is slow, maybe 1/2 what it used to be. We did adjust the linkage and I have reverse again when the tranny is cold. To add fluid though requires pulling the tranny which is no small matter. You can't even see the fill on top of the case because of the sheet metal.

Thanks Frisky.

I had to replace the drive belt on my JD three years ago. It helped to pull the sheet metal pan, which was easy to do. I then had full access to the transmission. IIRC, I only had to remove the seat, take out a few screws (maybe 4) and disconnect the operator presence switch underneath the platform. Definitely one of the easier tasks I had with it!

Good luck

Fred
 

jammar

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I, too, have a JD mower #LA120 with a failed hydrostatic unit. I only have 200 hours on the machine and feel that it is a very bad product. Manufacturing a unit that provides no method to change the oil with accessible drain and fill ports is a rip-off. My previous mower was an JD STX 96 that lasted 17 years, part of which I used commercially. It still works. The new machine is a total failure and expensive. The dealer quoted a new hydrostatic unit at $600.00. I have not tried to repair the unit yet but will remove the drive unit and see if there is a possible repair. I think the repair is probably not going to be possible but I hope so.

I hope this thread brings in a lot of comments as the number of buyers for the series 100 mowers is very large with a high percentage of failures based on the internet web sites.
 
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PJ

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I had a STX 38 and I had the same problem as you. Checked on parts to rebuilt and it was not worth the cost. Loaded it up and traded it in on a new deere. Gave me $400.00 for it.

Hi
I was offered 2 STX 38,s that is for sale. Do you think rebuilding and reselling is a option. I have a X140 as my personal mower

PJ
 
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