TC33DA 4WD won't disengage

[adlertom]

TC33DA 4WD won\'t disengage

I have a TC33DA with HST, supersteer, and sensitrak. My two options for 4WD are either engaged full time, or automatically engaged/disengaged by the sensitrak.

Today I was using the tractor on some muddy slopes, so I moved the lever to the full time 4WD position. After I finished working I returned the lever to the auto position. I could tell the 4WD was still engaged because turning was difficult. The inside front tire was scuffing the pavement during the turn.

Keeping the 4WD lever in the auto position, I drove around, backed up, turned, and generally played with it for quite a while. It still seems to be engaged.

Am I doing something wrong?

 

[thcri]

Re: TC33DA 4WD won\'t disengage

No I don't think you are doing anything wrong. Look at the linkage all the way down and make sure something didn't come disconnected. The other thing you can do is release the loc holding your two brakes together and while driving tap one of the brakes or the other. This may take it out.

murph

 

[PineRidge]

Re: TC33DA 4WD won\'t disengage

Assuming that you have a FEL use the bucket to raise your front tires off the ground. If you have drive line wrap up that should cure the beast, or at least get it out of 4WD.

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

Thanks, I'll check the linkage, and try lifting the front with the FEL tomorrow.

I read some of the earlier posts on this problem, but what seems different about my situation is that the 2WD/4WD lever moves freely, yet the driveline remains in 4WD.

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

Still stuck in FWD.

I lifted the front end with the FEL. When I turn one tire by hand the other tire rotates in the opposite direction, so it does indeed seem to be in FWD mode.

I checked the linkage, which consists of a cable running from the lever to the front drivetrain area. The cable is attached to a spring, which in turn is connected to a rectangular plate.

When I move the FWD lever, the cable moves and tensions the spring, but the rectangular plate doesn't move. So, it looks like moving the FWD lever isn't "telling" the drivetrain to do anything.

I've attached photos of the linkage in both the auto FWD (spring relaxed) and full time FWD (spring tensioned). Can someone explain what's supposed to happen here?

Thanks,

Tom

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

Here's the second photo - full time FWD lever position, spring tensioned, no change in position of the rectangular plate attached to the drivetrain.

 

[PineRidge]

Re: TC33DA 4WD won\'t disengage

Since we have the SS option also I'll run out to the pole barn and see what I can find out about the position of the plate. I think I can count on one hand the number of times that I have manually moved my 4WD lever. I'll be back in a few.

 

[thcri]

Re: TC33DA 4WD won\'t disengage

Tom,

I just went out and check my TC29D for the same thing. And I get the same results as you do. The rectangular plate doesn't really move. I can only see a difference in the tension on the spring. But I can tell a difference whether or not if it is in 4 wheel. One would think the plate should move. Any NH techs around to comment.

murph

 

[thcri]

Re: TC33DA 4WD won\'t disengage

Went back out and lifted my front wheels off the ground. My wheels will spin opposite of each other whether it is in 4 wheel or not. I also drove my tractor a bit putting in 4 wheel and out. I can tell it is going in and out as I put it in and out. Also my rectangular plate does not move. So I am not sure if that plate just looks for tension on it to determine 4 wheel or not.

Interesting to see what Pine comes up with.

murph

 

[PineRidge]

Re: TC33DA 4WD won\'t disengage

Both of your pictures appear to give the same lever position on the sensitrak transmission. Which is locked in 4WD.

On our TC-40D when I place the 4WD lever in the locked position it places the lever on the sensitrak transmission in almost a dead vertical position (retracted). Just like your pictures.

When the 4WD lever is moved to the auto position the lever on the sensitrak transmission moves forward to about the 5 o'clock position. (extended)

Look to see if your cable is free and check the lever in the extended position to see if there is some binding there. It may just be dirt creating a problem. Get some WD-40 in there. We are assuming that you are checking the fluid level of the sensitrak transmission at recommended intervals.

I will also say that our cable doesn't have the large spring at the linkage like your pictures indicate on your model.

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

</font><font color="blue" class="small">(
On our TC-40D when I place the 4WD lever in the locked position it places the lever on the sensitrak transmission in almost a dead vertical position (retracted). Just like your pictures.

When the 4WD lever is moved to the auto position the lever on the sensitrak transmission moves forward to about the 5 o'clock position. (extended)
)</font>

When you say retracted and extended, do you mean that the rectangular lever moves in an out as well as forward and backward?

Using the FEL, I lifted the front wheels off the ground again. Then, with the wheels up in the air, I tried moving that lever by hand. I could move the bottom of it forward to about the 5:30 position, but not to 5:00. It also looks like it's supposed to move in an out, but I couldn't move it that way either.

I also tried rotating the front wheels by hand while trying to move the lever, that didn't help.

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

</font><font color="blue" class="small">( Went back out and lifted my front wheels off the ground. My wheels will spin opposite of each other whether it is in 4 wheel or not. )</font>

Thanks Murph. I may have been wrong about that being an indicator of being in FWD or not. I really don't know for sure.

Interesting that your rectangular lever doesn't move either. It will be interesting to finally find out how this system is supposed to work.

 

[PineRidge]

Re: TC33DA 4WD won\'t disengage

<font color="blue"> On our TC-40D when I place the 4WD lever in the locked position it places the lever on the sensitrak transmission in almost a dead vertical position (retracted). Just like your pictures.

When the 4WD lever is moved to the auto position the lever on the sensitrak transmission moves forward to about the 5 o'clock position. (extended)
</font>

Sorry could have explained that a little better. When I said retracted or extended I was referring to the cable itself. So with the cable retracted the lever on the sensitrak is at dead vertical. With the cable extended the lever moves forward to the 5 o'clock position. When the cable is extended I can reach under the tractor and easily move the transmission lever either way, it seems to be spring loaded to the disengage side. Hope this helps you some.

 

[adlertom]

Re: TC33DA 4WD won\'t disengage

This is an update post to my 4WD disengagement problem:

The dealer mechanic came out and looked at it. He'd never worked on a Sensitrak however. He adjusted the cable tension so that less tension would be present in the auto position.

He said to try it and call back if any further problems. It's been working OK so far. It seems like a pretty fussy mechanism however, if just that slight amount of tension is all it takes to cause a problem. There's hardly any difference in the cable tension pre vs. post adjustment.

The mechanic was kind enough to let me photocopy a page out of his service manual that explained and diagrammed the sensitrak mechanism. I still don't understand it (it's sometimes hard to understand a 3 dimensional mechanism from a 2 dimensional drawing). I think I'll just leave it in the auto position from now on!

Anyway, all seems good for now. Thanks to all for their info and advice!

Tom