Tc 40 D keeps slipping out of 4wd!!!

[Rick1397]

Hi Guys!!!

I was hoping that you could again help me out with a problem I'M having with my 2002 TC 40D. I have posted several questions in the past about problems I had been having and as usual you guys are right on the money... I really appreciate the resource that Tractor by net provides, It allows us (not very mechically inclined) to consult with the opposite and hopefully resolve the issues that we encounter with our machines!!! and for that I thank you!!!:thumbsup:

As far as the current problem that I'm encountering in over the past several months it has been increasingly harder to switch between 2wd and 4wd-> I have noticed and read multiple posting related to this-> during operation occasionally the the manual selector would slip out of 4wd during this situation a loud claking would be heard during movement, I would stop and pull the selector into 2wd and it would operate as normal and then placing it back into 4wd it would operate as normal again Cont.

 

[Rick1397]

#2 I though that maybe the Linkage was either out of adjustment, or possibly dirt or corosion may be the culprit. So I took the wheel off so that I could disconnect, clean and lubricate all of the linkage connections ( it was a little slack so I tightned it up also) the actual component that goes into the transmission or transfer case??? (not sure what it is) it was undamaged and moved freely. So after everything was reassembled I took it for a test run and it did it again, still only occasionally and only under load (mud and going up extreme grades). So that is the current problem I am experiencing explained to the best of my knowledge. The tractor operates normally in 2wd. If you guys would be so kind to offer any suggestions related to what could be the problem, how to trouble shoot this problem and possibly a way to fix this it would be much appreciated!!!! I will be checking this post as much as time allows so if you can think of any questions that I didnt answer please feel free to ask. thanks again for your help!!!!!!

Rick

 

[jinman]

Rick, I think your problem may have started from the 4wd lever being bent and leading to 4wd not being fully engaged when the lever is all the way forward in the slot. To test this, I'd shift into 4wd without the tractor running and mark where the shifter goes to as it enters the shifter on the bottom of the transmission. Disconnect the linkage so you can rotate into 4wd without the linkage attached and see if the shifter shaft doesn't rotate a bit more. With the 4wd in this position (with the shift lever disconnected) drive your tractor to see if it will stay in 4wd without jumping out.

There's a chance that you have worn/damaged the gears so that they are now beveled and want to jump out of 4wd. I don't mean to say that this is your fault, it's just something that MAY have happened. If you are lucky, only your shifter linkage is bent and you may be able to manipulate it so that 4wd is more fully engaged.

I've attached NH's illustration of the 4WD driveline shifter box. In the illustration, item 50 is the rotating shaft inside the transmission. This shaft drives an idler gear, item 12. Item 39, is a gear that drives the splined output shaft, item 38, of the shifter box. It slides back and forth as you shift into and out of 4WD as a function of the shifter fork and shifter shaft (items 43 and 46) moving against the bearing, item 40, that pushes the sliding gear into position. I would disconnect the lever (item 48) from the handle linkage and try to engage 4wd using just this lever to see if could rotate the shifter enough to make 4wd stay engaged. That will tell you if your problem is internal or just bent shifter linkage.

 

[Rick1397]

Jinman,

Thanks again!!!! I'll see if I try that tomorrow.....if the problem is internal(hopefully not!!!!) are the gears something that I could replace myself for would that be a "dealer' only type repair??? thank you for the diagram it really helps to see what things look like...I'll let you how I make out....

Rick

 

[jinman]

Jinman,

Thanks again!!!! I'll see if I try that tomorrow.....if the problem is internal(hopefully not!!!!) are the gears something that I could replace myself for would that be a "dealer' only type repair??? thank you for the diagram it really helps to see what things look like...I'll let you how I make out....

Rick

Rick, I don't know how mechanically inclined you are, but disassembly/reassembly of the gearbox requires careful attention to the orientation of gears and thrust washers as well as needle bearing assemblies and sealing o-rings that need to be renewed when the gears are removed. You also have to drain the hydraulic fluid (probably about 7.5 gallons) and drive out rollpins with a drift-punch to remove the driveline going to the front wheels and also a shaft inside the gearbox has a rollpin retainer.

One nice thing about the gearbox is that you can remove it and inspect it without having to take it apart. If you see something wrong or a gear that needs replacing due to wear, you could probably take the whole gearbox to a dealer and get them to replace the worn part. That would save your having to take your tractor to the dealer. Once you have the driveline removed to the front axle, all you have to do is drain the hydraulic fluid and unbolt the gearbox to remove it. If you decide to go this route, be sure and write down the serial number of your tractor to take with you. In some instances, parts have changed slightly with different models of tractors. I don't know that it's needed, but having the serial number is just a good thing to do.

BTW: The idler gear and the sliding gear that mates to it are about $88 and $125 respectively. The illustration I posted is from Messicks. If you go there, click on the New Holland emblem/logo and then enter "TC40" into the block and look up your part under the Transmission head as "FWD Drop Box and Drive Shaft" heading. A complete list of parts and prices are listed by reference number callouts.

 

[Rick1397]

Jinman,

As usual you are amazing.....I wish that I could tell you that I am mechanically inclined but Im not really.... I can spin the wrenches however I cant trouble shoot and have no real knowledge of why certain things happen and how to rule out things based of symptoms (wish it could) I appreciate the tips you offer on how to do some things myself... I really enjoy doing the mechanical work but i think I will try to rule out the bent linkage (tomorrow) and maybe get lucky....if not I would leave the the really complicated stuff to the pro's!!!!.... I'll let you know how i make out.....

thanks again

Rick

 

[Rick1397]

Jinman,

Well, I have disconected the linkage and the same problem continued to happen!!!! I guess the problem is internally in the gear box (crap!!!!) about two years ago my local dealer closed and the next closest one is quite a distance away....so it looks like im going to try to remove the gear box and see if someone locally can rebuild it.... Do you know if there is any place that I can find information on the correct proceedure to dismantle or remove the gear box....hopefully then I can get someone to fix the internal components to get me back in business!!!!! I know that NH produces a shop manual however I was not really looking to speed that much at this time....any help would be appreciated!!!!

Thank again

Rick

 

[jinman]

Dang! Rick, I had high hopes it was just bent linkage.

Here is what I'll do for you. If you'll PM me with your regular email address, I'll email the pages out of the Repair Manual that apply to removing the 4WD driveline and dropbox. I want you to realize that I've never done this removal and disassembly. I have no expertise or experience beyond what I can read in the Repair Man'l. What you will have is written instructions for removal, disassembly, and re-installation. With that and the parts, an experienced mechanic should be able to do the job. You may even decide that you are confident enough to do it yourself. Just please realize the limits of my ability to help. After sending you the pages, I'll just be a cheerleader.

 

[farmacist]

Rick1397 I have been following your dialog with Jim and feel your pain. Before you start removing parts I just wanted to be sure that you followed Jim's instructions and did not just "try it with linkage disconnected". Review his first paragraph of his entry dated 3-19-10 at 10:11AM. Were you able to disconnect linkage and shift back and forth from in gear to out of gear? Did the shifter move further without the linkage than with linkage? Did you still get the problem when shifter was rotated all the way? I am just asking these questions to save you a lot of unnecessary work if it is not needed. These linkages do bend easily and impede the length of travel. Lets hope you have not damaged the gears. Best of luck, Frank

 

[paccorti]

I've just been looking in the repair manual section 23-4. This might not be that bad. It looks like the 4wd engagement is a small gearbox hanging off the differential. It does not appear that you need to split the tractor; the gearbox can be removed directly. I guess that makes sense when you consider that some tractors are not 4wd (and this gearbox adds that capability). From a manufacturing standpoint you'd like that to be easy to do. Notice detent ball #13 and spring #14 in the 3rd attachment. I think that holds the shifting fork (#12) into position. Part #12 shifts sliding gear (#21) into engagement for 4wd. Attachement #1 explains the overall operation.

Good luck,

Peter