450 TA

[FarmallLovinGuy]

I'm sure it's been asked 100 times here, so I apologize. How do I test the TA on a 450. Forward is disengaged and pulled back is engaged? If the TA is out, will the tractor not be able to move when the TA is engaged? Thanks

 

[the tractor vet]

The way i test them is getting the tractor warmed up a bit and then get it out and drive it on the mechanical T/A's i use forth gear full throttle and load the tractor with the brakes then pull the T/A once you have a good load on it and don't lolly gag pullen the handle back , it will eith make the shift or stop dead in it's tracks . Then ya know it is toast . Then ya rebuild or replace . Also look at the trans mission fluid as on them old girls it is neglected and not changed as it should be and is contaminated with water and age , some times it has the wrong fluid in it and if someone put 90 weight in it sure ain't helping T/A function.

 

[used red MN]

Tractor Vets post has some good suggestions in it but he tends to cut to the chase and hopes you are at a fairly high knowledge level towards your tractor. Not faulting him in any way just a different approach. First off your tractor that has what is referred to as a mechanical TA ..no clutches applied by hydraulic pressure... when the TA lever is forward the power flows through a smaller dry clutch behind the main clutch. In this position the power flow is direct through the TA and the input speed to the transmission is the same as the engine. When you pull back the TA lever back you release the small direct TA clutch and then the power flow is taken over by a one way clutch or sprague as it is referred to. This one way clutch is forced to over run while the TA is in direct due to different speeds the planetary carrier in the TA must turn due to the reduced gearing through the planetary gear set. The planetary gear set is always in mesh as well, that is the the reason for the one way clutch. Hopefully you know if a transmission is placed in two gears at the same time it will lock and not turn. So when the small dry clutch is released the main clutch now drives the sun gear of the TA planetary gear set. The planetary cage that had previously been turning faster slows and takes on the load of the power train which in turn tries to make it turn the opposite direction of power flow, but due to the one way clutch stopping it the power flows through the planetary gears driving the transmission through the outer ring or annulus gear which is also connected to the main transmission input shaft. Now the input to the transmission turns about 30 percent slower than engine speed. So TA lever back reduces tractor travel speed. Probably clear as mud. Back to testing the tractor. The tractor should start out and move with the TA in either position. And when in gear moving there should be a notable change in speed when the TA is shifted. If when the TA is pulled back when moving and the tractor stops especially under a load as the Vet describes the TA one way clutch has likely failed. One other thing you need to do if there is not a notable change in speed when moving the TA lever is to determine which range either direct or TA the tractor is operating in. To do this find an incline to stop the tractor on. Then shut the engine of and place the transmission in fourth gear and place the TA forward in direct. If when you let off the brakes and the tractor rolls forward ...without the engine turning.. the direct clutch in the TA has failed and the tractor is not changing speeds due to the fact that it is constantly operational in reduced TA speed. Sorry, this was long but I hope it helps.

 

[Janicholson]

This will also help. Jim
Video

 

[used red MN]

Thanks Jim, I actually was considering posting that video but I just didn?t feel it focused well enough on the section of the TA that changes speed during the shift. I think it would have been much clearer if the operator of the input crank would have kept a steady speed without starting and stopping.