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06' VF3 Gear Box won't go into low gear

Tom3197

Hot Rolled
Joined
Dec 21, 2008
Location
Cincinnati
As stated in the title we have a 06' VF3. 7500 RPM machine with a gearbox and it won't go into low. It seems we had this issue last year and the quick "fix" was to just warm everything up in high, after it was warm it would then go into low. Then have our second shift guy put it in low before powering off, then it would power up and switch gears just fine. Haven't had an issue with it all summer and now the issue is back.

Ran some parts in high gear on it today for about 6 hours, and tried to get it to go to low and it just won't do it.

Has anyone else has this issue with the gear box machines?

If so, how did you get it resolved? Just looking to see if there is anything I can do besides calling in a Haas Tech.

Thanks,
Tom :cheers:
 
Sounds like the little air cylinder that shifts the trans needs some loving.

IIRC you can remove it without removing the trans. It is somewhat of a bugger to do but possible.

The cylinder sits low and to the left on the outside of the trans.

If the cylinder is fine then you might have a bent shaft internal of the trans. We bent one once. If it's bent it's going to mean you need to make your own.:confused:
 
Thanks for the heads up ARB. I'll check out that air cylinder. I doubt we have a bent shaft though, can't recall any big crashes or anything.... at least not recently lol.
 
The air inlet to the shift cylinder has a small orifice to slow the air charge to the cylinder. That hole is about .003" diam and has proven to be a problem. We ended up drilling ours out a few thou to fix the problem. That most likely is your problem. If you follow the air lines to the back of the trans, when you remove the lines, you will find the little "pills" in there. If you find something in them, you know where your problem is.


Also, pull up your I/O charts and discover the trans L and Trans H bits. If you hear that trans actually shift and can detect it by trying to turn the spindle by hand, then the micro switches on the trans are gummed up and not moving. I cannot remember if you can access them from the inspection cover on the bottom of the head casting or not. If you cannot fix them, you have to remove the trans to replace them. I think that is a HUGE miss by Haas. That makes a 1hr job into a 10 hr job. You can kind of rock the trans forward for access but still requires orient reset, belts, wiring, etc. Not exactly exciting.
 
trouble shooting it

You will need to check if the problem is in the shifter or solenoids. If you unplug the solenoids and manual shift them (by pressing the botton on the end of the solenoid) does it shift. If so the problem could be the I/O pcb. If it still does not shif then pull the brass air lines off and open up the restrictor a bit. Also put some air gun oil in the brass lines to lub up the orings.
 
Thanks for all the input fellas.

Viper you nailed it man, thank you. It seems that since it has gotten cold we have a bit more moisture in our air lines... even though we have a dryer in line. I guess this allowed dirt to clump up and clog these pills more easily.
 








 
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