97 Gran Voyager Transmission Issue

[d55dave]

Hey guys, if I can get help anywhere I know it is here.

Our old voyager daily driver has developed (no surprise right?) a transmission issue. A little history - the van is a 3.3 4 speed overdrive and has 340,000 km's. Aprox 100,000 km's ago a rocker pedestal fractured off one of the heads so I replaced the engine and transmission with wrecking yard ones - I got a smoking deal on the drivetrain from a write off 97 Voyager. The transmission had obviously been recently rebuilt and had a new torque converter. It has worked flawlessly until this week, and only ever had ATF+3 or +4.

I know these transmissions are prone to issues, and aside from the differential pin issue I would suspect that thousands of them have been rebuilt when they didn't require it, due to a misdiagnosed sensor or computer issue.

Currently I am out of town but am trying to diagnose this over long distance so I can fix it when I get home.

The fluid level and condition are good, here are the symptoms. Everything seems fine and normal until the transmission shifts into high gear, at which point the transmission seems to slip (or engine freewheels?), with the revs climbing. When this happens the tach drops to a very low reading.

It would seem to me that this is the transmission entering limp mode, and after some research on the net I am guessing the input speed sensor is bad - causing the erratic tach readings and slippage as the computer does not know what is going on.

When I get home I plan to drop the pan, inspect for obvious metal / clutch and band wear debris, and try a new input sensor.

Sadly, we will not be able to afford to replace this van for another 6 months so I need to try and keep it running for a few more miles.

Any thoughts or input from any transmission experts?

 

[mark49]

sounds like overdrive clutches are gone.

 

[d55dave]

Is it true that with a scanner you can read the amount of clutch wear? I have done a couple of 727's and 904's, and had the pump out of one of the voyager transaxles. Is it a big deal to re and re the clutches and bands?

Thanks

 

[Tech857]

Hi Dave I would start with reading the codes from the tranny controller. Speed sensors can be monitored to see if they are working. It is pretty common for the gear train to break. Usually loose 3rd or 4th gear. This is a very easy tranny to rebuild but you do need a few special tools.

 

[transman]

Could be a combination of the solenoid and/or the speed sensors. Also, make sure your electrical connectors and their contacts are clean. While your at it, check all the electrics on the trans, PRNDL switch, range sensor etc. When I worked in the industry, we also sold a fair number of repair kits for the electrical harness connectors at the speed sensor, PRNDL harness and the speed sensors. And yes, with the proper scanner you can determine clutch wear. I don't know if your common hand held scanner will do this but the Snap-on one will.

 

[d55dave]

Thanks for the feedback guys. It will be two weeks before I am home to troubleshoot it - and if I want my pick up back from my wife I will need to fix the van! I will let you know what I find.