TH1860 Diesel Hydrostatic replacement?

[ScottQ]

Hello all,
New to this site but need some info if there is any! I recently purchased this machine, tried it out on flat ground and seemed fine. My land that I mow is pretty steep and after the oil in the hydro trans warms up it won’t pull hills in forward or reverse. I spent over $500 changing the Gerator, filter and several other items while I was in there, filled with new Castrol GTX 20w50 and it is no better. I was going to bite the bullet and purchase a new one and have found out that Hydro Gear no longer makes the complete units! I need to know if there is a replacement for this machine that will work or a shop that deals with these units for a proper rebuild? Looks like I can get one through Kubota but lists for almost $3900!!! If Hydro Gear still made it, I could get it for well under 1k???

 

[ScottQ]

I’m sorry! TG1860 diesel…. Fat fingers!

 

[Roadworthy]

I'll confess to knowing nothing about your machine but I can sympathize with your predicament. I ran into a similar issue with a Craftsman mower. Not wanting to pay $1600 for a new transaxle I replaced the fluid in the old one. If you slipping problem is a lack of fluid there may be a fix short of a rebuild. You could investigate that.

 

[ScottQ]

I'll confess to knowing nothing about your machine but I can sympathize with your predicament. I ran into a similar issue with a Craftsman mower. Not wanting to pay $1600 for a new transaxle I replaced the fluid in the old one. If you slipping problem is a lack of fluid there may be a fix short of a rebuild. You could investigate that.

I replaced with new fluid and filters…

 

[mikester]

Joys of buying used equipment...

 

[lugbolt]

is there any sign of leakage anywhere on the transaxle? If so, perhaps low fluid level causing your issue.

Yes you can change the fluid and they offer a filter, but it requires disassembly of the tranxaxle. There is no drain plug, so you have to remove it from the tractor and then take the lower cover plate off. It has IIRC 18(?) star head bolts that are harder than rocks, and almost always at least 2 break off during removal. Once the cover is off the filter stares you in the face. Use 20w50 engine oil to refill.

 

[ve9aa]

I have a TG1860 but am definitely no authority on them.

When you said ".... several other items while I was in there, filled with new Castrol GTX 20w50 and it is no better. ..."

Do you mean you filled the hydrostatic transmission with this oil?

IIRC <and I don't have the book in front of me>, I always top up the hydrostatic with a 90w oil. (I have a slow leak)

This could be your problem, if that's what you're saying. EDIT: I see various places online recommend 20w50 for the Hyrdrostatic, so I am not recommending you use 90w hydraulic fluid you understand....
It's just what I use in mine. I have 960 hrs on it and have owned it 15yrs.
I am not entirely sure where I came up with this oil spec.
Might've been the service manual, but I am not in front of it to consult.

This second idea isn't likely you're problem, but I also greatly improved the mobility and speed of mine going to a drive belt that was roughly 3/8" of an inch shorter than stock. I think I was getting slipping on the pulley's.

p.s.-your profile says you have a TG1869 (and looks like you noticed the typo in the subject line already ;-)

 

[ScottQ]

Right!?

Joys of buying used equipment...

 

[ScottQ]

I have a TG1860 but am definitely no authority on them.

When you said ".... several other items while I was in there, filled with new Castrol GTX 20w50 and it is no better. ..."

Do you mean you filled the hydrostatic transmission with this oil?

IIRC <and I don't have the book in front of me>, I always top up the hydrostatic with a 90w oil. (I have a slow leak)

This could be your problem, if that's what you're saying. EDIT: I see various places online recommend 20w50 for the Hyrdrostatic, so I am not recommending you use 90w hydraulic fluid you understand....
It's just what I use in mine. I have 960 hrs on it and have owned it 15yrs.
I am not entirely sure where I came up with this oil spec.
Might've been the service manual, but I am not in front of it to consult.

This second idea isn't likely you're problem, but I also greatly improved the mobility and speed of mine going to a drive belt that was roughly 3/8" of an inch shorter than stock. I think I was getting slipping on the pulley's.

p.s.-your profile says you have a TG1869 (and looks like you noticed the typo in the subject line already ;-)

The gearbox towards the front of the machine, in front of the transaxle takes 80/90w gear oil. Are you sure you are putting that in the rear transaxle?

 

[ScottQ]

is there any sign of leakage anywhere on the transaxle? If so, perhaps low fluid level causing your issue.

Yes you can change the fluid and they offer a filter, but it requires disassembly of the tranxaxle. There is no drain plug, so you have to remove it from the tractor and then take the lower cover plate off. It has IIRC 18(?) star head bolts that are harder than rocks, and almost always at least 2 break off during removal. Once the cover is off the filter stares you in the face. Use 20w50 engine oil to refill.

No leaks and it was full but the oil was dirty, removed bottom cover and changed filter put in new o rings and Gerator refilled through the vent port on top with new fluid and no better…

 

[ve9aa]

The gearbox towards the front of the machine, in front of the transaxle takes 80/90w gear oil. Are you sure you are putting that in the rear transaxle?

right or wrong, yes, I am 100% sure I am filling the rearmost box...where the axles come out. I believe this is the HST transaxle, not the gearbox....right between the wheels.

with 90W something.....took forever to get in via the vent tube. Thick like molasses.

As I said, it's what I did....maybe I read it wrong on the manual, but I went from almost no "go" to moderate "go" to really excellent "go" once I shortened up the belt. Now it pulls like a 4x4 with chains on the tires. The whole transaxle is not filled with it....I have a very slow leak (I notice little tiny dribbles on the ground in the shed where I park it and every 3-4 yrs, top it up) Maybe it's 100% wrong, but I've been doing it the last ~500 hours.

 

[ve9aa]

p.s.-you've used the word "Gerator" at least twice. What is that please?

 

[ScottQ]

right or wrong, yes, I am 100% sure I am filling the rearmost box...where the axles come out. I believe this is the HST transaxle, not the gearbox....right between the wheels.

with 90W something.....took forever to get in via the vent tube. Thick like molasses.

As I said, it's what I did....maybe I read it wrong on the manual, but I went from almost no "go" to moderate "go" to really excellent "go" once I shortened up the belt. Now it pulls like a 4x4 with chains on the tires. The whole transaxle is not filled with it....I have a very slow leak (I notice little tiny dribbles on the ground in the shed where I park it and every 3-4 yrs, top it up) Maybe it's 100% wrong, but I've been doing it the last ~500 hours.

What could it hurt? Mine is not working right anyways! I’ll give that a try, Thanks!

 

[ScottQ]

p.s.-you've used the word "Gerator" at least twice. What is that please?

That’s what the manual calls it, it’s a charge pump on the very bottom of the plate, supplies fluid to the main pump inside. I read it somewhere…

 

[ve9aa]

I stand corrected...I dug out my old paper workshop manual and you are correct. It says 20w50 for the HST.
Sorry about giving bad advice. Was not my intention.

I don't recall now some 12-13 yrs ago where I got the idea of adding a little 90w (proper for the bevel gear case,) to the HST, but probably someone on an internet forum told me to thicken up the oil and my leak would decrease and they were right. I have almost no leak today and drive is now strong.

When this all started, I had nearly no drive, (and at one point, no reverse !) so added (topped up) with 90 weight and then used a shorter belt and then finally the tire chains make it so I can drive up the side of my house (well, not quite, but you get the idea.)

Again, I am not saying you do this....it's just what this ol' goof did.

p.s.-My WSM (paper <c> Aug 2001) , HST chapter, makes no mention of a "Gerator." (whatever that is, LOL!)

Good luck.

 

[ScottQ]

I stand corrected...I dug out my old paper workshop manual and you are correct. It says 20w50 for the HST.
Sorry about giving bad advice. Was not my intention.

I don't recall now some 12-13 yrs ago where I got the idea of adding a little 90w (proper for the bevel gear case,) to the HST, but probably someone on an internet forum told me to thicken up the oil and my leak would decrease and they were right. I have almost no leak today and drive is now strong.

When this all started, I had nearly no drive, (and at one point, no reverse !) so added (topped up) with 90 weight and then used a shorter belt and then finally the tire chains make it so I can drive up the side of my house (well, not quite, but you get the idea.)

Again, I am not saying you do this....it's just what this ol' goof did.

p.s.-My WSM (paper <c> Aug 2001) , HST chapter, makes no mention of a "Gerator." (whatever that is, LOL!)

Good luck.

Thank you! I’m going to try it!

 

[ve9aa]

Thank you! I’m going to try it!

I used a clear hose for a filler tube instead of the black vent hose, so I could tell when I was close to "overfilling" (that makes a real mess and you risk getting "overspray" on your belt. 90W goes in pretty gosh darn slow, a dribble at a time and it was a total guess how much to add.

I don't think it was this thread but recently I mentioned that I found a drive belt at Princess Auto (like Harbor Freight) that was something like 3/8" shorter than stock and that also seemed to make a big difference in speed.

I think even the <expensive> stock belts from Kubota must have been slipping on the pulleys under stress.

Again , I am sure that I am just masking other problems doing what I did but this ol' beast just keeps on ticking even with my Mickey Mouse repairs. I only put on ~35-37hrs a year mowing 2 acres of grass. (iirc, 500hrs the last 15 yrs +/-)

 

[ve9aa]

and I feel I have to repeat that I am not a mechanic and have no basis for what I did other than someone, somewhere advised me of this the basically back where I was at where you were/are at now. I had nothing to lose as I was unwilling to invest many thousands into an old mower with 500hrs on it that I got for much less than the repair would be (that's another story).

I fiddle around with old cars, and know my way around electronics/electrical fairly well,. but if you blow up your HST, it's not on me, LOL!

Go easy---a little goes a long way. If you *think* you've overfilled, either suck some back out or cover over the vent cap with a rag or whatever so oil doesn't coming flying out all over your belt when the oil heats up. This happened to me one year when I got carried away---I believe the 2nd time I topped it up and I had to replace the belt. Now I watch very carefully my "oil spot" in the shed and "monitor" from year to year if I am losing speed. The more years go on, the better it is. (more 90w in there now I guess????)

YYMV and you're on your own ! (but good luck)

 

[ScottQ]

I used a clear hose for a filler tube instead of the black vent hose, so I could tell when I was close to "overfilling" (that makes a real mess and you risk getting "overspray" on your belt. 90W goes in pretty gosh darn slow, a dribble at a time and it was a total guess how much to add.

I don't think it was this thread but recently I mentioned that I found a drive belt at Princess Auto (like Harbor Freight) that was something like 3/8" shorter than stock and that also seemed to make a big difference in speed.

I think even the <expensive> stock belts from Kubota must have been slipping on the pulleys under stress.

Again , I am sure that I am just masking other problems doing what I did but this ol' beast just keeps on ticking even with my Mickey Mouse repairs. I only put on ~35-37hrs a year mowing 2 acres of grass. (iirc, 500hrs the last 15 yrs +/-)

I put new belts on from Kubota and it didn’t help, I will try this also! Thanks so much!

 

[ScottQ]

and I feel I have to repeat that I am not a mechanic and have no basis for what I did other than someone, somewhere advised me of this the basically back where I was at where you were/are at now. I had nothing to lose as I was unwilling to invest many thousands into an old mower with 500hrs on it that I got for much less than the repair would be (that's another story).

I fiddle around with old cars, and know my way around electronics/electrical fairly well,. but if you blow up your HST, it's not on me, LOL!

Go easy---a little goes a long way. If you *think* you've overfilled, either suck some back out or cover over the vent cap with a rag or whatever so oil doesn't coming flying out all over your belt when the oil heats up. This happened to me one year when I got carried away---I believe the 2nd time I topped it up and I had to replace the belt. Now I watch very carefully my "oil spot" in the shed and "monitor" from year to year if I am losing speed. The more years go on, the better it is. (more 90w in there now I guess????)

YYMV and you're on your own ! (but good luck)

Put on shorter belt ( tight now! ) and added at least a half quart and still no better…