RTV-X900: Transmission Slip or Normal?

mkruger21 · Jun 22, 2015

Hello everyone, new member here. I have read the miles of thread regarding slip/lack of power issues around the HST with the RTV 900 (which are quite dated, BTW).

I was going to take Matt's advice and adjust the servo valve adjustment but have found there must have been a signficant design change around the HST on the X-900 model since then. My unit does not resemble any of the pictures that were posted. I recall from the earlier discussion that Matt advised that if you are going up a hill, your engine should lose a little RPM, while you would lose several MPH. In my case, the engine is not losing any RPM and the speed drop is significant. I will engage the dealer on this but I am tight for time as I am preparing to go to Colorado. Is there an equivalent servo adjustment on the newer models that would help transfer a little more torque to the wheels? Or would this be a gunshot wound to the foot as we plan to be over 9000' most of the time? Please advise.

The machine in all other respects is fine, and I'm sure would pull out a stump if given the chance.

628pm · Jun 27, 2015

I have a x900, when going up a hill, it really drops down on mph, so I am in the same boat as you. One thing that does make an improvement is doing the spark arrestor maint on your muffler. Manual states to remove the bolt, have someone rev the engine a little while you are tapping on the muffler. I normally remove the bolt and drive it for about 10 miles, it seems to run better or I could just be imagining it running better. Keep us posted on what your dealer says.

JESSE1 · Jun 27, 2015

I love my RTVX-1100C except for the lack of power. The engine can be running full throttle and unless you back off on the throttle the speed is very slow to increase. Not a real problem unless you're trying to get somewhere in a hurry.

mkruger21 · Jun 27, 2015

I did talk to the dealer, and he did advise me that if the pressure relief valve (actuated by the brake to unload the transmission for easier shifting) is adjusted too tightly, that may make the slip excessive. It is a cable adjustment. I backed it off 2 turns and tested to make sure it would still unload the transmission. I took it out to my test hill, and it did make a difference. In low gear the speed change was slight. High gear lost about half the speed as before. The dealer did say that some loss of speed is normal, and the engine will not lose RPM unless the loading is severe. I would say that the major caution here is to make sure the unloader function still works to prevent future shifter fork damage.
I also drive a bit with the spark arrester plug out once in a while. That seemed to make more sense than beating on the muffler with a hammer.
Jesse, I've noticed that too, that stomping on the throttle is the fast way to go slow.

Thanks, Mike

kuboman · Jul 23, 2015

Have a RTV900 also that has excessive slip, but it is not consistent. I have adjusted the unloader valve but that had no effect. It seems if I back off on the throttle a few times it will become positive again. Any ideas? I'm not well versed on these trannys.

JESSE1 · Jul 25, 2015

When I changed my transmission and hydraulic tank oil a few weeks ago I used Kubota UDT2 synthetic fluid. At first I thought it was my imagination but it has really helped the performance of my RTVX 1100C. It has much better response and can actually hit top speed now whereas before I never could reach it. Kubota advertises that it helps performance and it really does.

mkruger21 · Jul 25, 2015

mkruger21 said:
... Is there an equivalent servo adjustment on the newer models that would help transfer a little more torque to the wheels? Or would this be a gunshot wound to the foot as we plan to be over 9000' most of the time? ...

Just got back from Colorado. The answer to the above question is that is a gunshot wound to the foot. The altitude is a BIG challenge to the engine, and so transferring more torque to the engine (for a given pedal position) does not help and in fact hurts overall performance. In fact, earlier threads have suggested using the optional hand throttle to rev up the engine and use the pedal to focus on gearing and I believe this would be the way to go...if you can't put on a turbocharger.

I visited with the shop manager at Southwest AG in Bayfield and he says there are no turbo kits planned or in the works for the X-900, due to space limitations on the vehicle. They were the shop that developed the turbo kits for the RTV900 and they currently provide them for the X-11xx as well.

All that being said, we had a great time in the San Juans, and among many other trails, I was able to coax the machine over California Pass (12,930 MSL) but it is probably not the best choice for this kind of riding. Because my wife is a rockhound, it did make a very good truck for carrying rocks.

mkruger21 · Jul 25, 2015

JESSE1 said:
When I changed my transmission and hydraulic tank oil a few weeks ago I used Kubota UDT2 synthetic fluid. At first I thought it was my imagination but it has really helped the performance of my RTVX 1100C. It has much better response and can actually hit top speed now whereas before I never could reach it. Kubota advertises that it helps performance and it really does.

I will be doing my 50 hr service soon and so I will try this.