454 TA, how does it work

peter123

Member
Hi
How does the TA work on the 454 series tractors?
I know there are 2 clutches, a plate clutch and a sprag clutch and an oil pump to provide operating pressure but that's about it.
Does the plate clutch engaged give high drive and when disengaged allows the sprag clutch to give low drive?
Does the oil pressure applied via the operating valve and pump engage the plate clutch - if so what holds the transmission with the engine off?

Or have I got it wrong? If so how does it give high drive

Reason for asking - occasional slipping in high speed.

Are there available repair instructions I have the 454 manual but there is nothing about the TA. Down load would be useful as I would rather not buy another manual just to repair the TA.
 
You sure need the master clutch but you can get all
that out of there without doing a double split and
you got to change the PTO gear and some other
stuff it can be done
 
I cannot find a diagram or information on a TA used in a 454. There was an 8 forward 4 reverse manual tran, and a hydrostatic
drive train. Neither had a TA. If yours does have a conventional TA, with a lever used to control a mechanical direct clutch, it
would have a handle with latching rear position for Low range.
If not it could have some other system I have not seen. The shifting is synchronized in the manual trans. Jim
 
(quoted from post at 17:32:52 08/16/17) I cannot find a diagram or information on a TA used in a 454. There was an 8 forward 4 reverse manual tran, and a hydrostatic
drive train. Neither had a TA. If yours does have a conventional TA, with a lever used to control a mechanical direct clutch, it
would have a handle with latching rear position for Low range.
If not it could have some other system I have not seen. The shifting is synchronized in the manual trans. Jim
The TA on the 454 was a option and is the same as all of the tractors that used the same transmission (454,464,484, 574,584,674) My manual covers all these types and the transmission would appear to be the same for all of these.

The tractor has 4 a speed transmission behind which is a 2 speed and reverse range transmission all of which need the main clutch to be depressed to shift. This gives 8 forward and 4 reverse manual shift gears. The TA is operated by a lever on the left of the steering wheel and that lever operates a valve located on the front end of the speed transmission section. The valve controls the oil feed from the oil pump that is located on a plate on the underside of the front end of the speed transmission section. The selection of the TA (in or out) does not need the operation of the main clutch.

I would still like to know what clutch does what and if the plate clutch is engaged for high speed, as per my original question
Also are there any repair instructions for the TA that are available online
 
Thanks for continuing this thread. My mistake was to assume you were operating a US version of the tractor. The European version
sure does have a TA on top of the synchro 8 speed. The TA is similar to the units found in the big frame tractors in the US. It
has two hydraulic clutches, and one sprag clutch. The front hydraulic clutch is stout and locks the TA assembly as a direct drive
to the transmission. It is not as strong as the dry clutch (main foot operated) because the torque applied to it is Less than full
engine torque (the effect of gears in the TA).
The rear hydraulic clutch is designed to prevent free wheeling down hills with the TA in reduction. It can handle engine braking
forces, but not as it would be used to slow from the higher gears (road speeds). It would rapidly wear out if used that way.
The sprag clutch absorbs all the counter rotating force applied to the TA carrier in reduction under load. It is also not
subjected to full engine torque due to the TA gearing. I hope this explains the clutches. Jim
Parts Diagram
 
Hi Peter123, I looked at caseih.com parts and the T/A is missing but go to 784 and Hydraulics in left pane and then 10-27 on
right pane will show you the hydraulic pump for T/A.
T/A is under Drive Train in left pane and 07-17 in right pane.

It is difficult to tell in HI T/A if it is the T/A clutch pack slipping or the main transmission clutch slipping. My brother & I
went through the same thing with his 684. We replaced the main clutch and that fixed the problem. Several years later, if the
684 was shut off on a slope in gear and without the parking brake on it would roll down the slope if it was in HI T/A. I
suspected that the T/A pump was weak or the check valve was leaking. He eventually had a retired IH mechanic install a T/A
eliminator kit in it.

JimB
 
Analysis: If the tractor is slipping under load (any gear) there are two aspects to consider.
Does the tractor slow down when slipping to less than the speed of the tractor when the TA is engaged? If so, the master clutch is probably slipping (foot operated, not TA). This would happen in either direct, or reduction.
If the tractor, in reduction, pulls as hard as ever and has no slipping evident, the issue is likely either worn TA front clutch, or low TA pressure. In direct, it would act like a 2 speed automatic shift. Starting out cleanly and then "shifting" to direct with slippage, a soft shift.
TA pump and control valving might also be responsible for the failure to lock up quickly.
This information is from information based on large frame IH tractors, and subject to interpretation related to the differences between them. Jim
 
(quoted from post at 21:40:12 08/16/17) Thanks for continuing this thread. My mistake was to assume you were operating a US version of the tractor. The European version
sure does have a TA on top of the synchro 8 speed. The TA is similar to the units found in the big frame tractors in the US. It
has two hydraulic clutches, and one sprag clutch. The front is stout and locks the TA assembly as a direct drive
to the transmission. It is not as strong as the dry clutch (main foot operated) because the torque applied to it is Less than full
engine torque (the effect of gears in the TA).
The rear hydraulic clutch is designed to prevent free wheeling down hills with the TA in reduction. It can handle engine braking
forces, but not as it would be used to slow from the higher gears (road speeds). It would rapidly wear out if used that way.
The sprag clutch absorbs all the counter rotating force applied to the TA carrier in reduction under load. It is also not
subjected to full engine torque due to the TA gearing. I hope this explains the clutches. Jim
Parts Diagram
Thanks for this, Sorry perhaps I should have said it a European tractor but I did not realise the difference.

So the front hydraulic clutch when engaged provides straight through high range speed and the TA gearing does nothing.
When the front clutch is disengaged the sprag clutch takes over and gives reduced speed via the TA gearing.
The rear hydraulic clutch prevents runaway down hill then the TA is in low.

Therefore when the front clutch is engaged the rear clutch is disengaged and the opposite would also apply - Correct ??
If there is slip in high and runaway down hill then either both clutches are worn or there is low oil pressure -Correct ??

What stops runaway if the tractor is left in gear with the handbrake off and the engine off so no oil pressure for either hydraulic clutch?
 
Correct on all points. I think it would roll down hill forward if left in a forward gear, or reverse if left in reverse. but nor
roll down if going forward and left in reverse or backward if left in a forward gear. The sprag clutch would lock it from turning
counter to engine rotation. Jim
 
(quoted from post at 16:42:25 08/17/17) Correct on all points. I think it would roll down hill forward if left in a forward gear, or reverse if left in reverse. but nor
roll down if going forward and left in reverse or backward if left in a forward gear. The sprag clutch would lock it from turning
counter to engine rotation. Jim
Thanks for all this info. I now understand what happens with the TA operation.
Is there any where to get rebuild / repair instructions as my 454 manual does not reference anything about the TA
 
Hi Peter, re what stops a runaway with engine off and no handbrake on, I believe there is a check valve in the hydraulic circuit
for the T/A and as long as the T/A clutches have no hydraulic leaks the T/A clutch will remain engaged with the engine off.
My brother's 684 would hold a tractor and load of silage on a hill with engine off until the T/A became worn out.
He also has a 3230 (newer model of 584) and it has the same T/A but is activated by an electric switch on the left of the dash.
The switch activates an electric solenoid on top of the torque tube that switches the T/A hydraulic valve. The T/A switch is
also in series with the clutch safety switch and everytime the clutch pedal is pushed the T/A drops into LO. This function is
supposed to make gear shifting easier.

T/A removal and repair is described in my I&T Shop Manual for IH 684.

JimB
 
(quoted from post at 21:37:31 08/17/17) Repair manual. Jim
This site has them.
Thanks for the site.
I have a manual covering 454 464 484 574 584 674 plus 766-1066 and 786 - 1086 and given the number of tractors with TA it is a disappointment that repair of the TA is not covered.

I was hoping to find something online to avoid buying another manual just to fix the TA.

Thanks for all your help.

Peter
 

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