What is TA

Jim Cox

I think you hear alot about it here because we are a buch of cheap skates. Always looking for that diamond in the rough.

Right now I cant tell you how hard it is or how much. I havent done one yet. Wait a few weeks I can let you know when I am done with mine.

The result of all this is many TA's packed up in the 1000 to 3000 hour range, long before they should have. Factor into this TA was also a pioneer attachment. Who was at fault is a hard call. I personally feel IH should have put a few more development dollars into TA and perfected it much sooner. Example freewheeling should have been history within 5 years.

We have absolute proof IH was on the right track with TA. Every major tractor manufacturer since has gone to 2, 3 and 4 speed power shifts. Deere and Ford both had complete power shifts for a number of years. That seems to have disappeared in favour of the gear drive transmission with 2 to 4 power shifts.

Having said all of this, I will declare that it was possible to take a new 300, 400, etc. and put 10,000 hours on TA without trouble, if proper care and maintainence was adhered to.

Another factor you are facing today is, as commercial farmers upgraded their tractor fleets, older Farmalls such as MTA, 300, 400, 350, 450, etc. became the tractor you parked at end of field with wagon and seed and fertilizer, or that spare tractor. The fact that when TA packed up the tractor would run for years in direct drive with no repairs, they were just left in that state of repair. No question in my mind Kelly, you could well be doing TA on a 400 that has been as it is for the past 25 years. To these farmers a 400 with low side out on TA was just as handy as a Super M

One of the hardest things on the TA was shutting down the tractor with the TA in the high side. If you ever had one apart you would see that if the engine turns backwards, such as dieseling when shutting down, with the TA in the high side everything locks up, sending a terrible shock through the TA with the overriding Clutch taking it the worst, causing flat spots on the ramps and rolling which lead to the clutch not locking up the go in the low side. If you shut in down with the TA in the low side everything with turn free to the transmission.

John In Iowa

Here is a post I made with I had to rebuild my TA on my 400 in 2001

Posted by John In Iowa on February 06, 2001 at 22:58:46 from (199.108.164.20):

After seeing a lot of posts about what causes a TA to go bad, I thought I would take the time to set things straight as I sit here tonight with my 400 sitting in a neighbor’s garage split in half and the TA case sitting on the bench with parts covered with clean rags waiting for Uncle Sam to return some of the money that he has borrowed from me (tax return). I got this 400 Farmall back in 1991 with the engine stuck. After rebuilding the engine and hearing it run, I was filled with joy only to discover that the over running clutch in the TA was weak. I did find out that after letting it warm up good that the TA would work most of the time. That was until this winter. I pull up to shed and got off to open the door to put it up for the night when the engine backfired, shuttled and came to a stop. The last time I heard an engine do that was when our family’s M broke the cam gear on the cam shaft (that’s another story). I pop off the disturber cap and found that I could turn the rotor any which way very easy and that my worst fears was coming to past. I got the other tractor out and push in the shed for the night and looked at it in the mourning. What I found was that the coupler from the hydraulic pump had come loose and the half moon key fell out. After putting everything back in order, I fired the old girl up and thought I would take it around the yard just to make sure everything was in order. I couldn’t move!!!! What I had found was about half the clutch face from the TA clutch laying in the bottom of the case and yes I had the TA in the high side. After taking it apart, looking at the TA and talking with some old IH hands I now understand what happen. The way the TA works is like this. You have an input shaft coming in from the engine that goes in to the planetary gear set. On this same shaft you have the TA clutch on it. On the gear set you have the pressure plate on the front side and the overrunning clutch assembly on the backside with the output shaft running through the overrunning clutch but not connected to it going to the output of the gear set. The outside part of the overrunning clutch assembly is bolted on the back bearing cage of the TA case. In this assembly you have 8 rollers that run up a ramp that lock the outside of the planetary gear cage to the back of the case, thus letting the input shaft turn the reduction gears in the gear set. On the high side with the clutch engaged the planetary assembly is lock with the input shaft, thus the output shaft is lock with the input shaft and turns the same as the input shaft. In the low side the clutch is released allowing the planetary cage to turn the opposed way until the overrunning clutch locks it to the back of the TA case stopping it and letting the reduction gears go to work. You would think that this would send a lot of shock through the TA but with everything moving it doesn’t. Were the real damage comes in is when the engine kicks backwards when you shut it off in the high side. With the planetary set locked to the input shaft with the TA clutch engaged, not letting any energy to go through the gear set and out the output shaft, it turn the opposed direction which engages the overrunning clutch which in turns brings everything to a halt. This is when you get a terrible shock through the whole TA assembly. One of the things that suffers the most is the rollers and the ramps in the overrunning clutch causing flat spots on the rollers and the ramps. With flat spots in the rollers and ramp its hard for the rollers to run up the ramps to engaged the overrunning clutch. In this case with me the overrunning clutch did hold this time tearing out the clutch in the TA. Coasting with the TA in the low side only lets the overriding clutch work like is suppose to, the same as if its in the high side. Hope this clears up some of the Myths out there.

John In Iowa