GT-14 Hydro advice

[Herder 2,354]

So the excitement over the 69 GT-14 is short lived.  Well not really I am still excited over the purchase.  I have had it home for two days which I spent the time going over every thing and changing fluids as I always do prior to use especially in a case like this when the unit has sat for many years.  So let me get you up to speed on the hydro. No pun intended.  I drained and flushed it and installed a new filter, at that point it seemed great.  Forward, reverse and the lift work, and when tooling around I was surprised how fast it is on flat ground.  It did lose some speed going up hill but at the time was nothing of real concern.  Today was the test I had a buyer for the 520-H and needed to get it up to the driveway and that's when it all went bad.  I an attempt to make it up the hill towing the 520-H the GT came to a stop and the hydro unit was struggling to move.  Afterwards I went back to the drain pan that had the old fluid form the hydro and dumped it into a waste bucket to see if I could find anything.  Yup, I did find some metal shavings.  Someone may have towed it or something.  

 

So where should I start?  Are newer hydro pumps and drive units interchangeable?  I have C-series hydro's ranging from 1975 to 1979.  The 79 is in a C-141 and I have to say was most powerful hydro drive I have ever had.  Rebuilding is always an option provided things are not shredded.

 

Thanks in advance.  

[953 nut 55,777]

@daveoman1966 and @pfrederi can add a lot to this. I would start with the Acceleration valves and springs as a likely problem.

Rest assured the options are out there. I used the Hydrogear pump and gear from a Charger to make mine good again, @19richie66 put an Eaton hydro in his GT-14, others have put eight speeds in GT-14s.

[daveoman1966 3,762]

What you've described is typical of a worn-out hydro pump.  A rebuild is not difficult...the exercise of getting it out and bolting it back into the tractor is the bigger half of it.  This is is Sundstrand Hydrogear model 90-2062 and, usually, a very robust power unit.  However, when dirt / debris gets into the hydro pump, damage is caused to the soft brass internal components, resulting is loss of pressure with ensuing power loss. 

If you can turn a wrench and know the working end of a screwdriver, you can manage the rebuild.  There is a manual to download for the rebuild on RS.  There are also several members that have contributed to this rebuild service, including me.  Not sure where the moderators have posted these reference files...but they are here somewhere.   Meantime, here is a pic or two of what you will find inside the pump.  

[oldredrider 2,549]

To answer your original question,  the newer hydros are not interchangeable.

The Charger and Electro pumps are the same. The hydro motors are the same with one exception: the output gears are different but can be changed to make them work with the GT-14.

I believe @953nut did a tutorial on the swap.

[953 nut 55,777]

You will find a lot of good stuff in this section on Red Square. https://www.wheelhorseforum.com/forum/144-transmissions/

 

Start with the service manual and look at all the springs and valves first. It is rather unlikely that they have been serviced for several decades. There is a trouble shooting section and some pressure test procedures you should do before diving in head first. As Dave said, these are not too difficult to work on and we have good members like him that will help you through the job.

 

[Herder 2,354]

25 minutes ago, 953 nut said:

@daveoman1966 and @pfrederi can add a lot to this. I would start with the Acceleration valves and springs as a likely problem.

Rest assured the options are out there. I used the Hydrogear pump and gear from a Charger to make mine good again, @19richie66 put an Eaton hydro in his GT-14, others have put eight speeds in GT-14s.

Thank you.  Funny thing about it I just sold the Eaton.

[Herder 2,354]

2 minutes ago, 953 nut said:

You will find a lot of good stuff in this section on Red Square. https://www.wheelhorseforum.com/forum/144-transmissions/

 

Start with the service manual and look at all the springs and valves first. It is rather unlikely that they have been serviced for several decades. There is a trouble shooting section and some pressure test procedures you should do before diving in head first. As Dave said, these are not too difficult to work on and we have good members like him that will help you through the job.

 

A pressure test is where I would like to start.  I would guess the metal shavings may by from the pump(?) I am not sure.  Disassembly may not be avoidable. Thanks for the info.  

[19richie66 17,522]

1 hour ago, Herder said:

Thank you.  Funny thing about it I just sold the Eaton.

I was just getting ready to say that. My transmission came out of a 520-H. All the motion linkage was from a 418-A I parted. It can be done but is a little bit if work. You do get a working brake out of it and not just a parking brake that will break off in the transmission if you use it while moving. If you decide later to go this route, let me know if you have any questions.👍

[Herder 2,354]

On ‎4‎/‎28‎/‎2019 at 6:33 PM, oldredrider said:

To answer your original question,  the newer hydros are not interchangeable.

The Charger and Electro pumps are the same. The hydro motors are the same with one exception: the output gears are different but can be changed to make them work with the GT-14.

I believe @953nut did a tutorial on the swap.

Summoning 953nut.  If you could share your knowledge and experience in this topic I would greatly appreciate it.  I pick up a 1969-70 charger 12 for parts and it has a good hydro pump so I am looking to do the swap.  The plan is to remove the entire drive unit from the GT-14 and spilt the case for inspection, cleaning and seal replacement.  Thanks.

Adam.