PTO Shaft Adapter 1 3/8 21 female to 1 3/4 20 male

[mchildress]

I have a JD MX6 rotary cutter I use behind a JD 5320 tractor. I got tired of breaking the yokes on the pto shaft that came with the mower and am working on putting in a larger pto shaft. The new pto shaft has the 1 3/8 6 spline on the tractor end and 1 3/4 female 20 spline on the clutch or implement end. The MX 6 has a 1 3/8 21 spline male. I have been searching adapters and only finding adapters to step down and not up. Just curious if anyone else might have run into this and found a solution?

 

[Andrewnewy]

Yes you have the wrong shaft, the 20 spline is for 1000rpm gearbox's
If you take it to your dealer they should be able to order you another coupling to go onto the yoke you have

 

[mchildress]

Yes sir I figured that out after ordering this one.Didn't realize there is a 21 1 3/8 and 20 1 3/4 spine. This is the 4th time I have broke a yoke on this mower and the dealer keeps selling me new yokes even though I insisted this drive line is not heavy enough. You would think the u-joints would be the weak link not the yokes. I have an older Rhino TW72 we mow the same ground with that has never given me a problem. So I am working on fitting a heavier drive line to the JD MX6 . I'm going to pull apart the clutch packs apart and see if I can swap out couplers.

 

[Tx Jim]

mchildress
I'll bet the slip clutch is rusted tight(won't slip). If you free it up and adjust clutch as per spec's the drive line problems will probably cease.

 

[mchildress]

Jim I agree that would be a problem. I just took the slip clutch apart a little dusty but not rusted. I don't think it could rust up as often as I have had to take it apart.The equipment stays in an inclosed barn and looks almost new. I rebuilt the clutch pack almost 2 years ago and threw the large tension washers away and replaced with coil spring tensioners. The clutch pack was slipping in heavy grass and I got tired of replacing the slip disk. I set the coil springs in the field were they would just not slip in the heavy grass. I know most are going to say slow down but this was happening as slow as I could go in low 1 and my son would pass me on the other tractor like whats up with my gear box blowing smoke from the slip clutch slipping. This mower came with a series 4 drive line rated at 40 hp. The tractor at 55 hp has torn up the slip clutch and broke the drive line at the yokes 4 times. Like I said above I have a Rhino TW 72 that we mow the same terrain,usually have both mowers going at the same time and not a problem. I believe most are running these mowers with 40 to 45 hp tractors and not a problem. Well any how I have swapped out the couplers and ready to see how the series 6 drive line holds up.

 

[Tx Jim]

JDparts.com only shows 1 drive line for MX5/MX6 and it has a cat lll u-joint. Plus JD's website lists the drive line under product spec's. for a MX6 as ASAE Category 3 with a 75 hp (56 kW) continuous / 90 hp (67 kW) peak. Series 6 drive line will probably take out the gearbox. I still think the original slip clutch/drive line has an adjustment problem.
Part Number: AE22753
Part Price: 16.50 USD
Description: CENTER CROSS CAT NO.3
Specification
Weight 0.95 LBS 0.43 Kg
Type Code 02
Diameter 1.126 IN
Diameter 1.126 IN
Height 2.626 IN
Length 2.626 IN
Series L14R

 

[mchildress]

I agree the slip clutch that came with it is self adjusting and was history at 1000 hrs. but had already taken 2 yokes out. That is when I modified it to the coil springs where it could be adjusted. I set it up to just not slip when in heavy grass going slow and still took out 2 more yokes. Never have had any problems with the u-joints and would think that would be the weak link not the yokes. It hasn't been just one yoke it has been on the front and back. It might of been cast problem I don't know. I can say out of the 5 tractors I have had this is the only drive line that has given me a problem. It is in the scrap pile now. I did pull two of the clutch disk on this new one to be on the safe side.

 

[Tx Jim]

I agree the slip clutch that came with it is self adjusting and was history at 1000 hrs. but had already taken 2 yokes out.

In all my 45+ yrs being associated with farm equip I don't remember seeing a self adjusting slip clutch. Looking at parts schematic I can't see how it could be self adjusting. Does operators manual state the SC is self adjusting? Have you ever contacted the JD dealer or home office about your drive line problems?

 

[greg_g]

x2. PTO drive line clutches are either adjustable (coil springs) or non-adjustable (Belleville springs), but not "self-adjusting". Some designs use both coils and Bellevilles. All require periodic maintenance - regardless of storage conditions - to keep from locking up during extended periods of non-use.

Evidence presented so far suggests that the OP slip clutch was in fact frozen when the 1st yoke broke. Subsequent tinkering with the clutch design is the likely reason for what followed. Those "large tension washers" by the way, were the Belleville springs; a key component in non-adjustable slip clutch design. And if the new drive line clutch has been been subjected to similar tinkering - even before first use - I anticipate further issues.

//greg//

 

[mchildress]

Here you go off JD spec sheet for MX6 cutter what they call a self adjusting slip clutch. Went through x3 sets of pads before up grading to the coil spring type clutch.
MANUFACTURER
MODEL John Deere
MX6
Capacity
Cutting Width, in. (mm) 72 (1830)

Cutting Height, in. (mm) 1 - 9.5 (25 - 241)

Cutting Capacity (diameter), in. (mm) 2 (50)

Cutting Chamber Depth, in. (mm) 8.5 (216)

Tractor Compatibility
Tractor PTO HP Range Minimum 30

Tractor PTO 540

Hitch
Type Lift-Type

Category 1; or convert to 2

Dimensions
Transport Width, in. (mm) 75 (1910)

Overall Width, in. (mm) 75 (1910)

Overall Length, in. (mm) 114 (2882)

Deck Shape Domed

Deck Type Double Decker

Deck Thickness, in. (gauge) (mm) ---

Upper .138 (10) (3.5)

Lower .138 (10) (3.5)

Side Skirt Thickness, in. (gauge) (mm) .25 (3) (6)

Approx. Weight, lb. (kg) 1041 (472)

Drivelines
Size ---

Main ASAE Category 3

Connecting ---

Protection ---

Main Self-adjusting slip clutch

Connecting ---
We have mow contracts through out the year and they really don't get a chance to freeze up. But over the years when I do suspect one of being froze I'll back off the tension springs and spin them then reset to spec.
I have 40 plus years operating and working on tractors also. Just the first time I have run into this many problems with this type clutch and drive line. Have repaired and set up many over the years with no problems.

Have spoke with JD and asked about upgrading to the shaft used on the MX7 and they kept throwing new yokes at me to put on it.They usually take a week or so to get the part in while the tractor sits idle costing me money. Yall take care and thanks for your input.