Farmall 666 Clutch Replacement

[dm2237]

Hello, I'm having clutch problems with my 666. It seems like I need to adjust it constantly to keep it shifting well, both the main clutch as well as the TA linkage. I know it's getting oil on the main clutch. Seems to be Hy Tran oil because I never seem to loose engine oil. So, I'm looking into splitting the tractor. If I split it, I'll put in a clutch kit, rear main seal and a TA clutch. What else should I look into replacing while it's open. I'm a firm believer doing the job once. Thanks, Dan

 

[caterpillar guy]

I think you will have a double split to do the TA as it is not in the same cavity as the main clutch. Some will be on here with better information on that part.

 

[BarnyardEngineering]

If you use genuine hy-tran it has a very distinctive smell that makes it easy to tell.

Oil on the clutch wouldn't cause you to be adjusting the linkages constantly. Are you adjusting back and forth, or in one direction only?

The TA clutch will come out without a double split but you do need to remove the PTO and IPTO shaft from the belly of the tractor. The IPTO driven gear partially blocks the TA clutch so it can't come out. It needs to be dropped out of the way to service the TA clutch.

 

[dm2237]

The engine clutch is slipping in high gear, when hot. It get hard to shift when it gets hot too. Same with the TA. I can adjust it so it's working, but it won't stay in adjustment. After using it, the TA doesn't work. You pull the handle back, but either it does nothing or it's like it's in neutral. Kinda hard to explain since I haven't driven it in a few months. It's put away for the winter. But it's like we need to adjust the clutch and TA almost daily to keep them working

 

[rustred]

Hello, I'm having clutch problems with my 666. It seems like I need to adjust it constantly to keep it shifting well, both the main clutch as well as the TA linkage. I know it's getting oil on the main clutch. Seems to be Hy Tran oil because I never seem to loose engine oil. So, I'm looking into splitting the tractor. If I split it, I'll put in a clutch kit, rear main seal and a TA clutch. What else should I look into replacing while it's open. I'm a firm believer doing the job once. Thanks, Dan

sounds to me like you need a mechanic to look at the tractor, since your asking what to look for.so it seems like you have never did a clutch job before. first u pull it apart then u make your need list. and this adjusting makes no sense, as we have absolutely no info on how u are going about doing this adjustment. pull it apart and do an inspection on everything, including flywheel as that may need resurfacing, p.p. my need replacing, check your clutch shaft spines for wear, throw out brg, seals and so on. make sure you know which way the clutch disc goes in. make sure you have absolutely no grease on the clutch flywheel or p.p. surfaces and wipe with brake clean. plus u will need a clutch aligning tool. use care bringing the halves of tractor together , and do the proper adjustment on the clutch free play the continue with the ta adjustment as per manual. and if getting into the ta thats another job. as you should be able to see the ta clutch then make a decision.

 

[BarnyardEngineering]

The engine clutch is slipping in high gear, when hot. It get hard to shift when it gets hot too. Same with the TA. I can adjust it so it's working, but it won't stay in adjustment. After using it, the TA doesn't work. You pull the handle back, but either it does nothing or it's like it's in neutral. Kinda hard to explain since I haven't driven it in a few months. It's put away for the winter. But it's like we need to adjust the clutch and TA almost daily to keep them working

"Acts like it's in neutral" means either your TA is shot or you're using heavy gear oil in the rear end instead of Hy-Tran. The TA doesn't have a neutral. If it's not in "high" it's in "low" because of the design.

This is why I asked about HOW you're adjusting it. First off what are you adjusting?

Does it seem like you're making an adjustment, and undoing that adjustment next time?
Does it seem like you keep adjusting it more and more and more in the same direction each time?

 

[dm2237]

I'm asking to see what else I need to look at. As for not doing a clutch job before, I work on tractor trailers for a living. I have replaced several transmissions and clutches, from full manuals to semi manuals that have clutch actuators and shift modulators and full automatics. I know I need to split it to see what exactly is going on inside. But it's not going back together, no matter what I find, without putting a clutch kit, rear main seal and TA clutch in it. I've done way too many of them half way because the customer didn't want to do the job right.

I run nothing in it buy Hy Tran. It's not going into neutral, just no difference when you pull the TA handle back. I adjust the linkage as per the shop book. Then it shifts great, and the TA works great. It just doesn't stay in adjustment. I wouldn't say that it's just back and forth with the adjustments, just constant adjustments to keep it working.

 

[used red MN]

If the TA sprague or one way clutch is functioning the tractor should drive through the TA in low just about no matter what except for complete failure of the TA planetary gear set. The TA direct clutch does exactly as its name implies, routes power directly through the TA and provides the Hi TA speeding. The direct clutch has to release to allow the sprag or one-way clutch to lock and power to flow through the TA planetary gears to provide a reduced drive speed. To avoid gear tension when stopping to shift and pressure is against the drive train trying to rotate it backwards the system has a way to release the TA clutch when the main clutch is released as in pedal down. Part 13 in the linked diagram which I will call the “TA clutch shaft release finger” is pushed by the main clutch shaft end lever bumper number 15 to accomplish this. If in TA Hi or Direct that TA shaft finger or the TA lever shift linkage cannot be holding the TA direct clutch partly disengaged. If it does the TA clutch can slip, this is the equivalent of not enough free play on the clutch. If the travel speed is not changing when the TA lever is shifted then it has to be determined if it is operating in TA Low of High. This can be done by driving the tractor down a relatively steep incline in 4th gear TA direct. If no engine braking then the TA is in low, if there is braking that is in hi which would mean the direct clutch is not releasing to allow low or reduction speed to engage.
Messicks IH 666 TA controls diag.

 

[Janicholson]

I'm asking to see what else I need to look at. As for not doing a clutch job before, I work on tractor trailers for a living. I have replaced several transmissions and clutches, from full manuals to semi manuals that have clutch actuators and shift modulators and full automatics. I know I need to split it to see what exactly is going on inside. But it's not going back together, no matter what I find, without putting a clutch kit, rear main seal and TA clutch in it. I've done way too many of them half way because the customer didn't want to do the job right.

I run nothing in it buy Hy Tran. It's not going into neutral, just no difference when you pull the TA handle back. I adjust the linkage as per the shop book. Then it shifts great, and the TA works great. It just doesn't stay in adjustment. I wouldn't say that it's just back and forth with the adjustments, just constant adjustments to keep it working.

If the TA position makes no difference there are two defining questions:
Does it free wheel in all gears in either position?
Does it stay in direct drive?
If direct drive, the TA front clutch is not being released. 7inch TA Throwout bearing pressure plate may be the issue.
If it slips (as indicated) in TA reduction, The TA sprag clutch (rear of TA unit) is toast. 2X split to change it. Jim

 

[dm2237]

When I adjust it, the TA works fine. When it's not working, it stays in direct drive all the time. It won't free wheel going down hills. That's why I was thinking the TA clutch was an issue. I know the main clutch is getting oil on it. That will make it slip, and can make it hard to shift and keep in adjustment. Not always, but it can. I have seen in on heavy trucks

 

[used red MN]

The TA throwout bearing may be the issue, as Jim said. If it’s wearing enough to change the adjustment that much other hard parts such as the release fingers may also be wearing to the point of needing replacing. You can look at the direct clutch and throwout bearing by removing the odd shaped cover held on by 4 bolts above the TA, the view is limited through.

 

[BarnyardEngineering]

When I adjust it, the TA works fine. When it's not working, it stays in direct drive all the time. It won't free wheel going down hills. That's why I was thinking the TA clutch was an issue. I know the main clutch is getting oil on it. That will make it slip, and can make it hard to shift and keep in adjustment. Not always, but it can. I have seen in on heavy trucks

There is an inspection cover over the TA clutch on top behind the bell housing. I can't remember if the console interferes with it on the 666, but I'm pretty sure it doesn't.

 

[dm2237]

I'll try to see in there when it warms up. It's only 17 degrees out today, and the wind is blowing. Way too cold to worry about it today. Thanks

 

[Janicholson]

I'll try to see in there when it warms up. It's only 17 degrees out today, and the wind is blowing. Way too cold to worry about it today. Thanks

If, at any lever position, the tractor stops, the sprag clutch is on the way out. Splitting at two points is necessary. a rebuilt TA is one possible solution (with a master clutch kit). The TA throwout bearing is also likely an issue. If you have experience with automatics, and manual transmissions, doing it yourself is reasonable. Jim

 

[dm2237]

Sorry for dragging this back up, but I finally got around to checking out the tractor. I removed the small plate directly over the TA clutch to inspect it. I found that 2 out of the 3 clutch fingers are missing. Would make sense since it has developed a terrible chattering sound in the TA clutch now. And it seems to be wet in there as well. I'll find out more when I split it apart I'm sure.

 

[used red MN]

Sorry for dragging this back up, but I finally got around to checking out the tractor. I removed the small plate directly over the TA clutch to inspect it. I found that 2 out of the 3 clutch fingers are missing. Would make sense since it has developed a terrible chattering sound in the TA clutch now. And it seems to be wet in there as well. I'll find out more when I split it apart I'm sure.

I am not sure why you would be sorry to update a thread on a problem with your tractor, that is the purpose of this forum. It would be good to determine if possible where the oil is leaking into the TA clutch cavity. Is it coming in more from the front or back. If you have to replace the two seals that seal oil from coming forward from the TA planetary section, that requires a double split and essentially the complete disassembly of the TA.

 

[dm2237]

Thanks for the info. It's wet inside the housing, but not soaked with oil. And the clutch doesn't appear to be wet at all. It will be interesting to see what happened inside there. None of the clutch parts look very old.

 

[560Dennis]

Have the flywheel inspection , surface cracks on 560 should not be longer than .50 inch. Then have flywheel resurfacing done correctly.
I had a tech at messicks send me the procedure for doing the resurfacing of flywheel for 560 correctly .
I don’t know what it is for that tractor . It’s not just take a cut off of surface and go .

 

[dm2237]

We get all our big truck flywheels surfaced at FleetPride. I'm not sure if anyone else around us cuts them or not.

 

[dm2237]

Ok, new problem. But related to the original problem. The tractor is stuck in 1st and 3rd gear. I was trying to get some things done with it before bringing it to the shop to split it. It was shifting very hard. Now won't move, and we can't get it out of any gear. We've tried rocking it and prying on the linkage, but nothing wants to work. What's the next step to do with it. It was scheduled to go to the shop this weekend to work on it next weekend. My fault, I should have left it alone until I got it fixed.