1968 IH 656 Diesel Hydro - 400 hours. Advice...

I am brand new to the forum and looking forward to participating when I can. I have read a lot of the opinions about the 656 tractors. I just bought a 1968 IH 656D Hydro with front end loader. Everything seems to work ok except for a few normal leaks. Hasn't been driven much over the past 7 years. Cranked and operated a couple times a year and that's it. I changed all the fluids and filters and seems to be running fine. Curious how to make sure the Hydro is strong as I know they are costly to replace. This is my first Hydro tractor. When it's in High range and going down hill it coasts and I must use the brakes to slow down. Is this normal? Works fine in L range though. Also curious to what you all think the value is, as it is in great shape. Look forward to hearing from the community! Thx!

When you say Hydro I think you mean TA which stands for Torque Amplifier. If so yes this is normal for it to coast downhill when the TA is in low range but not high range.

NO! it should not coaast in High range. The Hydro will hold back/stop the tractor on a hill.Leave at full throttle and just pull the lever back just as you would normally slow down.Easy test:While stopped (In high range) step hard on the brakes.At full throttle,push the lever completely foreward. That should stall or severely overload the engine.As fair as "expencive" to overhaul the transmission....no,not really. No more costly than any other transmission on any other gear drive tractor.Especially a JD powershift. And nobody ever seems to complain/badmouth those.Contrary to popular belief,you can 'farm' with em. However,they tend to use more fuel than a gear drive. That is because you set the throttle at pto/rated speed and use the lever to speed up/slow down.The hydro 'unit' is basicly nothing more than a hydralic pump and hydralic motor. they need good/adequet oil flow to work properly.Just put in Low range and rated or pto speed and plow. if hard pulling,wide open..I've been sitting on my 826Hydro the last several days 'stirring dirt'.I've owned 3 hydros(826.1026,Hydro 100).And I've been around/driven numerous hydros all my life.Plowed/worked ground all day long for days......Love those Hydros!

Everything DeltaRed said about the IHC Hydros AND one admonition: DO NOT pull start one! Without the engine running the 'charge pump' is not supplying oil to the bronze 'slipper feet' on the hydraulic motor 'swash plate' and they will be wiped out. The IHC mechanics used to check for bronze filings in the bottom of the case when a guy came in for warranty work on a non-operating drive and denied it if any were found as this told the tale: The tractor's operator hadn't read the owner's manual and had attempted to pull start it.

Thanks for all the advice! Well that worries me a little about the coasting issue..... It doesn't slow down when you pull back on the speed lever in H range. It does in the Low range, but high range pulls fine but when going down hill starts coasting.... Kinda caught me off guard the first time! Felt like I was on a runaway train! I will be doing most of my work in Low range, pulling a 22ft finish mower with it, but just wasn't sure if that was a bad sign about the Hydro or not. Will try the High/brake test today and report back.

The brothers who used to milk cows next door to me used to regularly destroy anvils with rubber hammers. They had a good yard of broken equipment but the Hydro 86 that they had didn't seem to have problems, and they traded it in on a smaller tractor after getting a bigger one that took the place of the 86. It had to have been a good tractor!

my suggestion for checking the hydro is a little different than delta red's.

With the tractor in low range, step on the foot-n-inch pedal (where the clutch would be if it was a gear drive), move the hydro lever into the blue area of quadrant, half throttle or so, hold the brakes, and let out the f-n-I pedal. A good hydro will overpower the brakes. In high range, same procedure, it should stall the engine. If the hydro starts whining instead of moving, the hydro has a problem.

as noted before, yours shouldn't coast in high range. may be adjustment?
also, as noted, you can't start it by towing. if you need to tow a hydro, put the hi/lo lever in neutral or you will hurt the hydro.
they are a very useful transmission if maintained correctly. you will love it for harvesting work. i put a lot of hours on an 826 hydro, pulling a 5 bottom plow. it was still going strong when dad traded it off on a new 1086.

Freewheeling is usually caused by the snap ring coming off the end of the shuttle valve

Is this something I can easily fix myself, or does it need to go to the dealer? Where is location of the snap ring? Again, thanks to everyone for
you help and advice!

Disregard my previous message. I was thinking of our old 560 we had at home 35 years ago.

So the Hydro passed the test. Pulled strong in low with the brakes on, and really bogged down when in High range. So I am still left to wonder why the High range goes to freewheeling when I go down a hill. You can't pull back on the speed controls like I do in Low range, have to apply brakes to slow down going down a hill. High range will pull you right up a steep hill. Otherwise the tractor seems to operate just fine. Open to suggestions.... Thx!

The shuttle valve is not too difficult to service. It is accessed through a hole in the Hydro housing that has a large pipe plug in it. when the snap ring comes off the usual symptom is that the tractor will not move forward from the neutral position until you first put it in reverse.

Another possibility it the drive control valve either is out of adjustment or has a spring problem. That is the valve that is activated when you move the speed control lever to either side before going forward or backwards. Try holding the speed control lever more to the side when slowing down and see if that changes things.

(quoted from post at 04:31:15 03/28/15) The shuttle valve is not too difficult to service. It is accessed through a hole in the Hydro housing that has a large pipe plug in it. when the snap ring comes off the usual symptom is that the tractor will not move forward from the neutral position until you first put it in reverse.

Another possibility it the drive control valve either is out of adjustment or has a spring problem. That is the valve that is activated when you move the speed control lever to either side before going forward or backwards. Try holding the speed control lever more to the side when slowing down and see if that changes things.

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Seems like I went out on a service call about 40+ years ago to a ranch in Gunnison county that had a fairly new, at the time, Hydro 100 with the same problem - wouldn't hold back downhill with a Chuckwagon on behind - IF I remember right the guy had never greased the drive control and that was the fix - the zerk is accessed by popping out the round plug-cap on the left side of the console. It seemed too simple at the time but that was all it took :roll: