John Deere 770 Clutch Adjustment

[crashz]

Got the tractor out last weekend and did some mowing for my aunt and uncle. I cut down a field with grass/weeds about 4 ft tall with a 5 ft bushhog cutter. It ran very well, in fact it seemed to run better the longer and harder it was pushed. Its been a long time since I've used it so that may play into it.

I did notice that the clutch pedal is grabbing a little high, so I'm going to addust it per the owners manual. I'd had this machine for nearly 10 years and ~250 hours with 1024 hours on it total. Thsi machine has the dual stage clutch and has primarily been used as a little loader to plow snow and pick stuff up in the past. The owners manual shows a single adjustment for free play measured at the pedal by adjusting a threaded rod within the linkage. Seems simple enough. Is there anything else I'm missing?

 

[Tractor Pilot]

crashz,

That is the only adjustment for the clutch on the JD770.

I adjusted the dual-stage clutch on my 1997 JD770 last year around 550 hours. My Operator's Manual (OMM95326 Issue J0) for the 670/770 says if the free travel is 15mm (5/8") or less to then adjust the free travel to 35mm (1 3/8"). My Technical Manual (TM1470 15MAR99) for the 670/770/790 says to adjust the free travel to 18-22mm (3/4"-7/8").

Not sure why the difference in specs between the two manuals. I went with the TM spec since it was the most current manual.

Bruce

 

[crashz]

I measured my peddle free travel to be about 1", so per the manuals I should be OK. I didn't do anything to the cltuch thios weekend. Just ran it some more!

 

[PRIMEMEDIA]

I just purchased a JD 670, can you tell me where the clutch adjustment rod is located.

Dewayne

That is the only adjustment for the clutch on the JD770.

I adjusted the dual-stage clutch on my 1997 JD770 last year around 550 hours. My Operator's Manual (OMM95326 Issue J0) for the 670/770 says if the free travel is 15mm (5/8") or less to then adjust the free travel to 35mm (1 3/8"). My Technical Manual (TM1470 15MAR99) for the 670/770/790 says to adjust the free travel to 18-22mm (3/4"-7/8").

Not sure why the difference in specs between the two manuals. I went with the TM spec since it was the most current manual.

Bruce[/QUOTE]

 

[garygehrts]

the difference is between the single stage and two stage clutch specs

 

[Tractor Pilot]

the difference is between the single stage and two stage clutch specs

Thanks for the reply, Gary. But which measurement is the single and which is the two-stage clutch spec? My tractor has the two-stage clutch.

 

[garygehrts]

Thanks for the reply, Gary. But which measurement is the single and which is the two-stage clutch spec? My tractor has the two-stage clutch.

If you have 4wd then you have a two stage clutch. My 2007 790 4wd manual states 1 3/8" travel of pedal. Per dealer, there have been complaints on the abrupt engagement of the clutch so they have issued the change in the travel if you would like to try it. It is the same travel (3/4") setting for the single stage clutch. I purchased this machine a month ago and the first thing I did was change the setting back to 1 3/8" as it had been adjusted to the 3/4" travel play by previous owner. He stated he had the dealer do it as he did not like the way the clutch engaged but said it was even worse when he got it back. It still is a little jerky but way better than when adjusted to the 3/4"

 

[Tractor Pilot]

That you for the information, Gary.

So to summarize:

For the John Deere 770 Clutch Pedal Free Travel there are two specs:
1. Single-Stage Clutch: 3/4"-7/8"
2. Two-Stage Clutch: 1 3/8"

John Deere currently recommends that the two-stage clutch also be adjusted to 3/4"-7/8" for smoother operation. However, owners of the two-stage clutch may find that the original 1 3/8" adjustment is actually smoother. Try both and see how your particular JD770 responds.

 

[jscusmcvet]

Bringing this old thread back to life. Can someone describe how you measure the free play and then where to adjust it if needed?

 

[Tx Jim]

Pedal free travel is determined by how far pedal can be moved forward or down before contact can be felt when throw-out brg contacts pressure plate fingers or diaphragm which ever applies. Adjustment is made by turning turnbuckle the correct direction to gain correct clearance.