MF 70

Hello, this seems to be THE place to go for old tractor info, so I thought I would ask you guys. I am looking at buying a MF70, and everything on it operates fine, except high range. Are there any simple checks I can do before buying it to determine what is not working properly? Low range seems to work fine, but the seller says that when shifted to high range it won't move at all. I don't really need high range for around my place but it would be nice. Could this problem eventually lead to Low range not working as well? Thanks in advance.

Hi Greg,

I am not familiar with an MF 70, but am somewhat with the 65. My I &T service manual lists the 50, 65, 88 and 90, but not a 70, so anything I propose is possibly only conjecture, though because Massey seems to have tended to keep things fairly consistent between models of similar size...

I assume it is a 3 speed transmission, with a High/N/Low shifter on the right of the transmission cover, and that 'range' shifter isn't working in High, correct? Or does this model have a lever on the dash marked high and low? If so, it's a Multi-Power, and the issues with those have been well documented on the board here.

If it isn't a Multi-Power, it is possible that the splines of the transmission input shaft have gotten stripped, but more likely that the linkage from the range lever to the planetary pack at the transmission input has sheared a pin on the shift fork.

Either way, if there isn't a lot of metal debris circulating in the transmission, and if it currently works in 'low', it will probably keep working that way without further problems.

Before I were to tender an offer on it, I'd pull the drain plug on the transmission first (with a 5 gallon bucket in place and another right behind it) to check for metal. The drain plug should have a magnet on it, and anything more than a few fine flakes is likely a bigger problem waiting to happen. There would be no way to tell the full extent without pulling the transmission cover.

There are some folks here who probably have dealt with that exact problem, and who would know more than I can guess.

Let us know what you find.

Well Worn

Thank you for this info. The trans is only a two speed - H/L, Forward/Reverse, with the shifter on the dash. So I guess it's a Multi-Power. I will do some searching. Thanks again.

(quoted from post at 19:34:48 04/01/14) The trans is only a two speed - H/L, Forward/Reverse, with the shifter on the dash. So I guess it's a Multi-Power. I will do some searching. Thanks again.

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Greg,
Not so fast - I appears I was wrong and should have done some research before taking a guess - the 70 is an industrial tractor with a 2 speed automatic transmission, not a 3 speed manual (with a possible multi-power) as I assumed. The MF70 base specs are here: http://www.tractordata.com/backhoe-loader/000/1/1/113-massey-ferguson-70.html

That type of tranny is beyond my tractor experience (even though I've done some automotive automatics), and without a service manual to see how it's put together and is supposed to function, I'd be hesitant to offer a guess as to how reliable it would be, probably depending on the reason(s) the high range isn't working - anything from a cooked or shreaded clutch pack, to a stuck check valve. I suppose it depends on how dependable you need it to be, and whether the probable cost of rebuilding the transmission is factored into the price you are willing to pay.

Sorry to have set you down the wrong path.

Well Worn

An MF70 is a large industrial backhoe loader
weighing about 18,500 lbs. with a cab. They were a
very good heavy duty machine in their day. They
used a 2 speed torque converter transmission. MF
made an even bigger version in the MF80. Maybe the
torque converter is gone or leaks? An older MF
dealer may have some information on the
transmission or check with a heavy equipment repair
shop. Good possibility of finding manuals for it on
the internet.

The transmission is a Clark HR28000. The shop manuel doesn't have a trouble shooting section for the trans. I would check to make sure the shift valve is moving all the way.

Thanks for the info. I went ahead with the purchase, for the price I couldn't pass it up. It needs a few small things done, but seems to run great, and has nearly new rear tires. I will start looking for info/parts for this trans.

Well after getting it home and checking a few things on it, it turns out the pressure to the trans clutches is fine, but the pressure to the converter is low. The manual states that it should be 80-100psi warmed up @ 2K RPM. I only see 80 when cold, and as it warms up the pressure starts dropping. It doesn't have the power to push much dirt with the bucket even in low. And I did get it to shift into high coming back down my driveway, so the clutches seem to be fine, just not getting much through the converter. I will pull the charge pump when I have some time and disassemble and check the pressure regulator and relief valves.

So, I took the charge pump off, and found that the spring in the pressure regulator block had worn through the wall of the casting separating it from the bore for the pump shaft to pass through. I decided to make a sleeve to press into the pump shaft bore, since there was ample room, to seal off the spring pocket. This brought the clutch pressure up a bit, but did not help the converter pressure. So the next thing that the manual says to check is the converter for leaking seals. But to order seals I need the model number off the data tag that is missing from my trans. Does anyone here have a '70s MF70 that has the transmission data tag on it? And could I get that number? I am told it should be something like " XX HR28XXX". Thanks.