TA trouble IH 3388

huib · May 18, 2015

I,m having trouble with the TA on my IH 3388, when in HI, and taking off ,it will start in low and directly shift to high, it should not do that, I have read that if low goes on the TA it should still operate in high,is that true, it is also slipping in low at times. Are there any adjustments on the TA that could be the problem?

pete 23 · May 18, 2015

You need to adjust the dump valve. That is the valve that opens when you press the clutch pedal down. Little quarter inch rod with threads on the end. Adjust it so your transmission oil red light goes out before your tractor begins to move. That will get you away from the double shift. Slipping in low has no adjustment as it a over running clutch (sprag) that drives in low TA. You may very well need to do the entire adjustment on the clutch, dump valve and transmission brake as too little or too much clutch free travel will aggravate the dump valve adjustment.

huib · May 18, 2015

Thanks Pete, I did the adjustment on the dump valve, what is the purpose of this valve? Is the TA suppost to have pressure in Hi and non in LOw?,can it be that it is getting some oil and make it slip?

pete 23 · May 18, 2015

The purpose of the dump valve is to dump all pressure to the TA direct drive clutch or anti free wheeling clutch pack in low TA when clutching so that the tractor gears can unwind, (roll back). If you were to unhook the dump valve and drive up an incline, when you depress clutch the tractor would not roll back. That keeps pressure on gears called gear windup and you will not be able to get it out of gear. Because the low side is a one way clutch that portion can never roll back (unless totally worn out and anti free wheeling clutch also not working) so therefore we have to release the direct drive clutch to allow gears to roll back. On mechanical TA's we released the direct drive clutch with a linkage or pulling TA lever for the same reason, allow unwind of gears. Wet clutch's always have some drag on them even when released until they spin a little. That is why even with dump valve releasing pressure you still have some resistance to rolling back. A good trick is to just apply the brake when pressing clutch and that will allow the gears to relax much quicker provided you are not coasting of course.

huib · May 18, 2015

So if dump valve would stick somewhat in open it would not go in low TA, or slip?So no pressure on TA is LOW

pete 23 · May 19, 2015

Low side TA does not require hydraulic pressure so if dump valve sticks out a good ta will still drive in low but not in Direct Drive (HIGH) side. Even a bad TA on low side may pull very light load because it has the anti free wheeling clutch discs locked up with pressure but they won't pull much. It is the mechanical sprag that pulls in the low side of TA.

TA trouble IH 3388

huib

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pete 23

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huib

New User

pete 23

Well-known Member

huib

New User

pete 23

Well-known Member

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