Farmall 400TA issue

[Dutrup]

Hello, the TA in my 400 row crop does not change/shift between low and DD. I can move the lever forward and backwards but there is no change in speed etc. I do not know which side, low or high it is seemingly stuck in.
Secondly there is no slipping of the drive components. It s rock solid.
Third if I am on an incline or have a loaded wagon or anything that exerts a, forwards/backwards, force on the tractor it becomes a monumental task to get it out of gear even with the clutch depressed and TA handle pulled back. The tranny is tightly bound. I have meticulously adjusted the clutch and TA linkages per the book to no avail. I have tried adjusting the linkage in other manners but no help.
The tranny is not stuck in two gears. I am familiar with that problem and it s remedy.
I opened the top of the TA housing and the TA clutch, pressure plate, fingers and throw out bearing all appear normal. When I fully depress the clutch pedal the TA clutch does open.
This all started, without warning, while we were moving implements around the barnyard and does it every time.
I have had 5 of these mechanical style TA tractors and I have never experienced this phenomenon.
I am looking forward to your knowledgeable responses.
Thanks

 

[tractorsam]

It sounds like its stuck in high T/A, if you can see the
clutch opening I wonder if something s keeping the disc
stuck.

 

[the tractor vet]

Well with having a problem with in and out of gear this is a T?A clutch problem of being out of adjustment . Now due to age and extensive field testing of said tractor Throw the book away on adjustment due to ware . Take a long look at how all the linkage is hooked up . You will see a rod and clevis coming off the bell crank and rod going into the bell housing pull the cotter pin and remove the pin going back the the other bell crank setting back from the bell housing , NOW do the main clutch free play adjustment and you will want and inch or so between the clutch pedal and the deck plate . once that is done also remove the one spring on the Linkage on the T/A rod . Next is to hold the T/A bell crank to the left so that it makes contact with the T/A clutch throw out bearing. ( you can remove the inspection cover of top of the T/A clutch and look down in to make sure . It is held on my four bolts under the gas tank . WHILE holding the T/A throw out bearing against the T/A clutch fingers now hold the linkage clevis up to the hole in the main clutch bell crank and install the headed pin and see if you have ABOUT 3/16th inch FREE play and then adjust to have that . when ya have that you are set . Now Ya check to see if the T/A handle moves when you push the main clutch down if it moves then ya adjust just enough so that is does not move when you depress the foot clutch but will still disengage the the T/A clutch when you pull the T/A lever back .With the lever back and locked this is when you are in LOW and when forward your in HIGH . On a side note here When your in the low side the tractor will free wheel down hill so never think your going to go down hill SLOWER IN THE LOW SIDE , it will be and EYE opener. One thing one should invvest in is and I T manual for his new toy , they are NOT the best manual but they are vary helpful the Other manuals some clam are better still leave out some of the important stuff due to copyrights . I am not a computer wizz so i don't post LINKS to parts pages that any one can access . I just know how to FIX what others Don't Now as to the rest of your T/A problems i need more info .

 

[the tractor vet]

Well if it IS a stuck T/A disc man that is a super easy fix with out splitting required just three longer bolts so not to have to fight the T/A pressure plate and pull one headed pin and get the throw out bearing away from the fingers and remove the other three short bolts after you installed the three longer bolt then one stiff bladed putty knife and a HAMMER . NOW there also could be other problems .

 

[BarnyardEngineering]

I would think you could just pull the TA lever and go at it with the putty knife.

You can also pull the cover off the planetary section of the TA unit, directly behind the TA clutch inspection cover. I was told by an old IH mechanic that if the TA is working properly you should be able to roll the planetary section over by hand in one direction but not the other.

Inspection under that cover may also reveal other issues, such as something in the planetary broken and jamming up the works.

 

[Dutrup]

Thanks for the input. I know the TA clutch is free from the pressure plate. I have seen it gap. I will check that it is not stuck to its flywheel. I will report
back .

Secondly could a badly worn TA throw out bearing cause this issue? When looking in there it seems sloppy but the way they are mounted it is hard for
me to tell.

 

[BarnyardEngineering]

Could a badly worn throwout bearing cause the issue? Sure but if the clutch is releasing from the pressure plate and there is a visible gap that is not the problem.

Either the clutch disk is stuck to the flywheel or something is lodged in the planetary.

 

[used red MN]

I believe barnyard may have the answer. It is possible something has failed in the reduction planetary gear set. If something locks the planetary gears from rotating what you are experiencing is how it would react. For the TA to release for easy shifting when back pressure is on the speed transmission gears (gearshift) it relies on the planetary gears to be able to rotate turning the released TA direct clutch free the binding. Also with locked planetary gearing when you release the direct TA clutch the planetary gears cannot transmit a rotation load back against the planetary carrier to engage the one way locking clutch. So essentially you have no reduction gearing either. This may make very little sense to you but I feel this is a fairly accurate description of what could be happening. If I am ever given the opportunity to have a torn down TA I would like to make a video that explains how the TA works, I feel it would be very helpful in these situations. Here I go with a link, not that it is extremely helpful because the assembly is pretty complex. I will link the manufacturers online parts catalog for your tractor. Go to section 12 Chassis, then subsection 264 for the Torque Amplifier. If you want an actual IH repair document for the TA email me and I will respond with a link. I do not feel it is right to post the manual link here due to the fact that are forum hosts sell repair manuals.
CNHI Farmall 400 online parts catalog

 

[Dutrup]

Gentlemen, I was carefully inspecting that the TA clutch disc was free of its flywheel. While depressing the clutch I was able to rotate it easily one
direction. While doing this I discovered an issue that I really do not believe was there a couple nights ago. One of the fingers for the TA pressure plate has a broken pivot point and does not return to the
relaxed, or flat, position. Will this, in itself, cause this my problem? Apparently the clutch is still releasing or it would not turn easily.??? True?
False? So obviously I need to split it. But the question remains is this the only problem or the result of me over adjusting the linkages to get it to work. Thanks again.

 

[the tractor vet]

Well now that is going to require a split to fix , and that looks like a new break . So this is a reason you ee3l no change in speed and also why your having hard shifting . No9w as to why , well something caught and caused the tear off of the stand and finger.

 

[used red MN]

I was going to ask about that but you seemed pretty confident that everything looked okay. The TA in my uncles 300 has that same issue now, his has two pin mounts broke. It has had the issue for probably over 8 years. The rest of the tractor really did not warrant repairing it. Now something has happened to the engine. He has a 350 that needs a motor and we swapped an entire rear end that seemed to have far less hours on it a one point. So if he was going to repair one the 350 would probably be the one.

 

[Dutrup]

Ok now, or when I split it, are there any tests I should perform on the TA to insure it is ok? Obviously I would prefer to split it only once. Thanks

 

[used red MN]

In direct when there is no tension against them they wiggle around and wear the holes in the pressure plate and they get thin and break out. But centrifugal force is holding some pressure against them as well. Also the bearing that holds the direct TA clutch gets some play and hangs down and when you pull the TA back it has to kind of center itself on the fingers, again adding wear on the finger pivots. Though the transition from direct to TA is pretty quick. Not sure if you realize this but in low or reduction the direct pressure plate is stopped and being held by the one way clutch. In the end it is not uncommon for them to break like this due to wear. The designer should have made them a little beefier to start with.

 

[the tractor vet]

It takes all three for things to work . Now from what i see that does not look that old , so something happened to cause this . One side to the release fork could have broken ?? and snagged the finger , might be incorrect adjustment that forced the fingers down to far???? . I am not the one standing over it to see the whole story and you probably not even close to me to come look . Now will replacing the pressure plate solve all your problems i can't say . Is this a tough job ?:? well not for me as i have been in a bunch over the years . Now also you may find that the T/A carrier nut has backed off once you dig down into it , this happens when some one did not have the correct tool to torque that nut down and set the lock tabs . This will also cause a direct drive problem . Me i would FIX but that is just me as i fix things right the first time .

 

[BarnyardEngineering]

(quoted from post at 19:24:59 04/06/23) Gentlemen, I was carefully inspecting that the TA clutch disc was free of its flywheel. While depressing the clutch I was able to rotate it easily one
direction. While doing this I discovered an issue that I really do not believe was there a couple nights ago. One of the fingers for the TA pressure plate has a broken pivot point and does not return to the
relaxed, or flat, position. Will this, in itself, cause this my problem? Apparently the clutch is still releasing or it would not turn easily.??? True?
False? So obviously I need to split it. But the question remains is this the only problem or the result of me over adjusting the linkages to get it to work. Thanks again.

<img src=https://www.yesterdaystractors.com/cvphotos/cvphoto151808.jpg>

In the immortal words of Mythbusters Adam Savage, "There's your problem!"

Yes, that would prevent the TA from shifting and cause your other shifting issues.

It will require a split to fix but only a single split. The TA clutch system can be removed through the bell housing.

 

[used red MN]

What you might find is some worn parts. Replacing those parts will require a double split, meaning the TA section has to be pulled off the rear transmission and final drive section. I recently helped another 14 year old that had posted here with some info about the TA in his 450. He sent this picture of the splines his TA clutch plate sat on. As you can see a lot of wear on the narrow part the plate sets and drives on. During that time I found the attached videos of a guy working on his 300. This guy is learning as he goes so not the best how to video but it shows the items I want to point out. Watch part 5 at 6:50 to 7 minutes he quickly shows a shaft he pulls out with a coupler sleeve on it. That is the shaft that the main clutch drives, the splined coupler he shows engages the less worn section of the splines shown in the picture. In part 6 in the 2nd link watch the entire first part mainly starting at 40 seconds and through 4:30. It also shows the same spline sections worn in his TA. He shows the splines that the rear section of the TA dry sets on being worn quite a bit as well. Also he shows the one way clutch and the problems with them. Replacement of these parts require a double split. If you have looked up rebuilt TAs which sell between $600 - $900 they include these worn shafts. So there are some items to ponder.

Video Part 5

Video Part 6

 

[Dutrup]

Thank you gentlemen for your continued support. Since planting season is rapidly approaching splitting this tractor will most likely get held off till our
crop is in the ground. I will post what I find.
I rounded up some of my tractors I thought you may enjoy seeing.
Take care.

 

[the tractor vet]

Ah no , the clutch and pressure plate come out the top , not the bell housing , you remove the input shaft out the ft after ya remove the thrown out bearing support just make sure you put the input back in the right way .