TA question

I've seen a lot of Farmalls for sale with "TA weak" or "TA needs work". I'm wondering if not having the TA working properly or at all has any effect on normal tractor operation, or if you'd only notice it if you tried to use the TA while plowing or doing some heavy pulling. Would a tractor with a weak TA be fine as is for light duty, or would it have to be fixed before any use?

been runing a 3688 with a weak ta for about 6 yrs. only thing is the clutch can be real jumpy for some reason. when we finnaly get around to doing the ta should do clutch anyway .

It doesn't hurt a thing. Just make sure there are no other tranny issues.

The following is basically true. Exceptions can be found, and the blur at the transition to high HP, European, and CaseIH tractors is not included.

There are three clutches in a TA drive (and a PTO clutch)train in SMTA, X00, X50 and X60 tractors. They are the main tractor clutch controlled by the foot clutch pedal.
The TA Direct drive clutch (looks, and is like a smaller regular disk clutch with a pressure plate. It is controlled by both the TA lever, and by the master clutch pedal motion. The third "clutch" is a one way clutch. (think of a quiet ratchet that allows turning one way but locks the other) it is not controlled by the operator.
The main clutch is just that it operates just like a normal every day friction disk clutch. If worn, it slips, if greasy it slips/chatters, if good it holds well. it can be either composite friction material, or ceramic puck style (spider/puck).
The TA direct clutch is used when the TA lever is forward. It is composite, and when engaged, it locks the TA assembly together causing it to turn as a unit. this provides direct drive. The TA direct clutch can be smaller because the torque applied to it is much smaller than total drive line torque.
The one way (ramp and rollers, or sprag type)clutch operates when the TA direct clutch is disengaged. The TA planetary gears (like in an auto trans)are free to turn when they do the TA gear housing trys to turn backwards (in reaction to gear reduction inside)this retro turning is stopped b the one way clutch being attached to the frame casting of the tractors transmission. This causes the gears to turn the transmission input shaft at a reduced (~30%)speed.

If the master clutch is weak the tractor drive will slip when loaded, or starting in higher gears.

If the TA direct clutch is weak, it will slip in direct drive and seem like it goes into TA "automatically" because it will still pull like it is in TA low. (this will happen for a short time because the TA direct clutch will be toast, then it will seem like it is in TA low all the time.

If the one way clutch is getting bad, it will either sometimes work in TA low, or slip out of TA low into a neutral like don drive condition.
It can also just not move in TA low when the one way clutch is toast.

The higher HP newer tractors use a four clutch system also, but the TA direct and rear TA hold clutches are hydraulically operated. This change does not affect the concept of operation.

Always move the TA lever (all kinds) rapidly into and out of TA; prettymuch as fast as possible W/O letting go of the lever.

Never use any TA to try to ues engine braking to slow. The mechanical TA is only able to free wheel in TA low and will destroy itself if coasted down a hill in gear faster than direct speed in that gear (the TA housing will spin up faster than the engine and can come unglued with explosive deterioration!!) Further, the coasting is dangerous and un controlled.
The hydraulic TA will hold back on down hill coasting, and is OK to use that way!!---But-- only if you are at that speed in TA low already, never put it in TA low to try to slow down. It can slide the tires and wear out the clutches as well as break parts. Not good. This is all there is to it at a basic level.

They are 10,000 hour devices if used often and correctly. Their reputation (with good operators and proper adjustment/maintenance is golden and they are a great feature.

If ignored or used by slow lever motion or speeding down hills, they die. Then the owner blames the TA. It is exactly the same as using any sophisticated equipment. Do it well maintain it properly, and it will serve. I hope this works for you. Let me know, JimN

I've been using my 300U without the TA for ten years. I have the TA lever tied to the frame with plastic ties so noone can move it.

Dell

In my experience there really is no such thing as a weak TA. The term "weak TA" is only used by sellers that are unwilling to actually say the TA is out. My father always said...."TA's are like being pregneant, no middle ground." One could interpret a TA that will move an unloaded tractor but wont move a loaded one in low range as weak, but if it wont work in the situation it was actually designed for, is it really of any value? I've bought and sold (mostly IH) tractors as a part time job/hobby for going on 35 years now. Adjustment is CRITICAL, but I have yet to find the first one that adjustment will bring back to life and make dependable. I'm sure others may have different experiences there. That being said, and being winter, I have had tractors that the TA will slip in low in the cold and couldt find a way to make them slip when the weather warmed up. Usually a fluid change would them make them work in the cold as well.

We have a 350 and a 560 that both have TA issues. I just don't use it. Both tractors are used only for light work. If I used them for heavier work, I'd probably fix it. When I worked for an IH dealer, we had a few customers that took the TA out. I could never figure that out. There really wasn't much of a cost difference.

Thank you JimN for one of the better notes I've read on the operation and proper use of the SMTA-X50 TA's. Your post should have been used by IHC in their operators manual. It's a good explanation to help operators get best use out of a TA. I printed it and stuffed into my manual. Thanks again. ag

You are very welcome. The topis is a bit tough to make clear. Thanks JimN

I have several IHC tractors with TAs that seem to slip ---- more at a given time than the next time ---- which makes me think the fluid, whatever that maybe, is the PROBLEM. So I go to a IH , sorry CASEIH dealership, and ask where the drain plugs are located ? where is the fill port ? quantity to fill ? Obviously the questions didn't get answered so if there is one among you that can help , I am gratful. I do know the correct oil to use but have been told by other collectors of finding GL5 & similiar heavy oils in TAs. "that's what Dad put in the '40 M !" Thanks for your help.

Jim Kuntz, I hate to dash your hopes, but it is not the fluid.

If the TA is slipping, hopefully it is just out of adjustment, but more than likely something is wrong. As I understand:

1. Slips all the time: Main transmission clutch is shot.
2. Slips only in "high" TA: TA clutch is shot.
3. Slips only in "low" TA: Ramp and rollers are shot.

The TA shares the same oil with the transmission. It's not a separate reservoir. Whatever is the right oil for the transmission is the right oil for the TA.

I just checked my 400 and 450 manuals, and they call for 15 gallons of SAE10 engine oil with a "Torque Amplifier Additive." I believe HyTran is the modern equivalent.

Pretty much any tractor with a TA should have CaseIH Hytran or an equivalent oil in the transmission.