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345 trans slipping
- Thread starter cliffblue
- Start date
- Views: 6012
Flying MXZ
Bronze Member
New drive belt and idlers. I felt like the trans should still be ok at 1287 hours but I don't really know. You can fully press the reverse pedal and you can hear the hydraulic whine real good when it doesn't want to back up. Is there a rebuild kit or will I need to just open it up and start looking for bad parts? The manual does go into a lot of detail, but it will be time consuming. Thanks for the input. Cliff
Don't you let off these hydrostatic transmissions to go up steep grades?
I'm not sure I understand your question. If I nose down and need to reverse, it does not want to go. As the trans gets warmer, even less so. We're not talking serious grade here. Forward is better but still not strong. The manual does not consider any part except the pumps with this problem. In checking one site only, looks like a lot of unavailable parts involved. There are rebuilding or rebuilt swap sites out there. Anybody try this?
Flying MXZ
Bronze Member
Ok, sounds beyond what I know. I think to go up steep hills with a hydrostatic transmission you don't want to push the peddle down all the way. Let off to lose speed, but gain "power".
bruceatlam
Platinum Member
Cliff --- I know that you don't want to hear this and I'll own that I could be wrong, BUT, this sounds like a loose/worn/wrong/installed wrong drive belt problem to me. You said that you bought all JD parts so I assume that you have the right belt. When you start to write about lack of power going up/down any little hill, I think immediately about living through that same problem when my main drive belt is worn out. That's exactly how my hydro behaves ----------
Sorry ---- I won't mention it again.
Sorry ---- I won't mention it again.
Hey Bruce, no problem. I appreciate the interest. While the belt is the correct one and new, I did run into the differences of belts for the 345 under 70000 vs 70001 and up. The early models <70000 like mine, use a conventional v belt design. Later they used a double v type that used flat idlers for both sides of the belt.
One reason I lean toward trans hyd problems, is when I have to push the pedal down all the way to get motion due to a grade, the trans really whines that hyd whine. If I had belt slippage, I don't think it would really whine like that. I had one summer on it when I changed the in line filter after starting on the vac in the fall. Everything underneath still looked ok. Like you, I'm no guru. I'm just looking at options. Thanks again for taking the time.
One reason I lean toward trans hyd problems, is when I have to push the pedal down all the way to get motion due to a grade, the trans really whines that hyd whine. If I had belt slippage, I don't think it would really whine like that. I had one summer on it when I changed the in line filter after starting on the vac in the fall. Everything underneath still looked ok. Like you, I'm no guru. I'm just looking at options. Thanks again for taking the time.
bruceatlam
Platinum Member
Well if you're convinced that the problem is internal to the pump, then the reference to "whine" leads me to relief valves. See post #9. There are two in there -- they're both available --- one from JD at about $60 and from from an OEM parts seller for about $50. Both new at a total of $110. If I were you, I think that I would buy them and then set about to tear it down and clean it up well and replace those relief valves. If you find something else along the way --- so be it. There are other reasons to lose pressure but I don't think that they would produce the "whine".
What did you neighbor say?? Did he notice that behavior when he owned it??
What did you neighbor say?? Did he notice that behavior when he owned it??
oldnslo
Super Member
Cliffblue,
I would be a little surprised if it is a slipping belt since the operation of the transmission changes with temperature. HST transmission function getting worse with temperature points towards a failing component in the tranny itself. In looking at the parts break down on the JD site I could not see any system relief valves in the HST (trans-axle). This would indicate that the design of this machine was for the wheels to spin to limit system pressure. NOTE: JD may have an option for work port reliefs on the HST. This also appears to be a semi-sealed trans-axle assembly so there is limited heat rejection capabilities so running the HST at higher loads causes higher leakage which translates to higher heat dissipation required. Higher temperature means thinner oil which leaks more which causes even more heat...
I would be a little surprised if it is a slipping belt since the operation of the transmission changes with temperature. HST transmission function getting worse with temperature points towards a failing component in the tranny itself. In looking at the parts break down on the JD site I could not see any system relief valves in the HST (trans-axle). This would indicate that the design of this machine was for the wheels to spin to limit system pressure. NOTE: JD may have an option for work port reliefs on the HST. This also appears to be a semi-sealed trans-axle assembly so there is limited heat rejection capabilities so running the HST at higher loads causes higher leakage which translates to higher heat dissipation required. Higher temperature means thinner oil which leaks more which causes even more heat...