Another CVT issue

[CMF_Rich]

I have done searches, and found nothing like my issue, so here it goes.

'95 K11, CG13DE 102,000km

My wife called me the other day and reported the car was having an issue with "shifting". I test drove the car and found the same issue she is having. The car will accelerate normally but does not allow the car to go beyond 30km/h. When shifting into Ds, the car acts exactly the same. I checked the linkage on the trans case, and it is shifting from D to Ds normally. I have no fault codes on the CVT light, or the check engine light.

The car was acting normally the night before the problem was found.

Shy of the typical "change to a 5spd" are there any ideas? We will only need the car to run for the next 6 months till my wife and I leave Japan.

 

[CMF_JKL]

A line pressure test will confirm pump pressure. Usually in the side of the pump housing there is 2 or 3 10ml size blanking plugs or allen keys that allow for line and pump pressure testing. Its pretty easy if you have the tools and can access a workshop manual.
If pump pressue is down, this is more than likely to wear than failure. If there was mechanical failure its unlikely you would have "any" drive gears.
You may be able to do "temporary" fix be using an oil additive or "thickener", this can overcome pump wear and return normal shift patterns the oldest of transmissions and CVT systems. There are a few brands out there available from most spare parts shops.

 

[CMF_Rich]

I sadly don't have access to a manual, so I am going to have to go on the good graces of this forum to supply images. I have a workshop with lifts, and about 16 years of turning wrenches.

Would this wear be the source for the problem we have had for the longest time, where the trans would slip during acceleration intermittently?

 

[CMF_JKL]

Yes, the pump is driven by the engine and generates pressure for the solenoids and internals to operate and change gears. Spead sensors 1 or 2 and engine load then determines which gear you should be in.
I can get the name today of the additive if you like. It might be the "quick and easy" answer you need, for now.
Ill see if I can locate the line pressure specs and location of the plugs. A simple oil pressure guage will work, you will just have to make up an adaptor, to suit the transmission thread size. -Shouldn't be too hard.
The pressure tests are done usually at a specific COLD Temperature and at a couple of RPM stages. Eg: 35deg c, 1500RPM/ 35deg c 3000rpm etc.

 

[CMF_Geoff W]

Dont forget that the K11 CVT transmission has a kevlar belt inside that needs to be changed every 100 000km. It is after all a belt driven system as I understand.
The worst part by far will be the labour side of things.

 

[CMF_JKL]

The hydraulic tensioners should maintain tension even if the belt has stretched. I think Belt fairlue is the main concern regarding the service interval. The car does have drive so I'd be suprised if it was a faulty drive belt.

 

[CMF_Geoff W]

Fair enough.
I thought that it was a logical assumption seeing that they have experienced slipping in the past.

I have driven a CVT Micra with a belt slip problem and it's downright dangerous. Not to mention annoying.

 

[CMF_JKL]

AHH.. OK. I missed that! "slipping in the past"
Still, if pressure can be increased with lowering the oil viscosity it may increase tension and reduce slip.
CVT was going to be the "next big thing" but it just didnt fire did it.....

 

[CMF_Yom]

CVT is firing right now.

THE americans have caught onto it in a big way.

But the theory behind it has changed somewhat.. Its a bit more than belt on a cone at the moment.

 

[CMF_Rich]

Okay, the slippage I had in the past wasn't bad at all, it just happened when I would start needing more than normal torque. We just had a typhoon rip through so not much as been done. How can I get the viscosity of the oil to increase? I am assuming that it is standard ATF fluid, so I can just get a thicker variant of that?

We are going to get the car atleast running at normal speeds and dump it to the first person with 120,000 yen. So I only need a fix for.... 2 weeks.

 

[CMF_JKL]

Go to supercheap or autobarn and get a 750ml bottle of "transmission stop slip". Its as thick as sh%$ and will be an effort to get into the trans but it will increase pressure and hopefully reduce slip.It comes in a white bottle with red writing and also blue writing. Its usaually kept with all the engine flush and wynns additives.

 

[CMF_Rich]

That would be awesome if we had Supercheap or autobarn in Japan. I will see what I can find locally that does the same thing.

An idea my wife had this morning is...

The bottom corner of the windshield above the passenger's foot well, is leaking slightly, this is causing some issues with the blower motor for the heater/AC. Where is the CVT control module located. What is confusing me is that if the problem was slow in coming it would have given us warning. The problem we have of staying in the "Ds" range happened over night. The car was working perfectly when she drove home from work, parked it at the house, and the next morning BAM no drive

 

[CMF_Rich]

anybody...this car is about to go to the junker.

 

[CMF_Rich]

I found the maintenance paperwork from the previous owner, and the CVT fluid has not been changed in over 60,000km. I did the swap today, and the car seems to not slip at all. But the underlying problem is still there. There is no change in the car's performance or operation between D and Ds. I pulled the relay for the CVT controller and started the car. The red N-CVT light came on, replaced the relay and the light was gone.

Is there a way to run a diagnostic on the system using parts a shade-tree mechanic has around the house?