CAT 426 Transmission

[aschumann28]

Hello Forum I am new here.

I have a CAT 426 Backhoe with trans#F7-2017.Serial # 7BC-0**** The backhoe is 1992 ish. It wont move forward or backwards.
I checked the fluid and now I am worried, the fluid looks milky which usally when I see that I think water in the mix!! I looked up in the manual and it says the fluid is just SAE 30. So I interpret that as just as 30 weight oil???

as far as not moving I was gonna trouble shoot the neutralizer solenoids but I first wanted to confirm or deny my suspicion of water in the fluid?? and if confirmed can I flush the system or what would be my next step.

Thanks

 

[Diesel_doc89]

we had the same thing with a bobcat we were working on. what happened before it wouldnt move? was it jerking? on the bobcat it was a diode in the reverse solenoid causing it not to go forward or backward. on the hydrostatic oil/ trans fluid. i would use the CAT hydrostat trans. oil. on the bobcat the fluid looked like a milkshake and smelled like diesel. we think someone confused the tanks because they were identical. but we drained the tank and put in the 25 gal. of fluid.there was still a good bit of fluid in the lines so it still had a somewhat milkey look but after the nexs flush im sure it will look better

 

[Mobiltech]

First check electrical . There should be a neutralizer switch on the trans gear shift knob it can cause it to stay in neutral

 

[aschumann28]

It was working during the day then in the afternoon it stopped working. I had to use the buckets to get it back to my shop. The next morning went out to trouble shoot and it was working again. Then later after working for an hour or so it stopped and thats it it hasnt driven since.. I check the fluid levels which were within normal operating range, but that was when I noticed it was cloudy or milky, I didnt know if an additive was added and made it look that way or what... I am gonna check the nuetralizer solenoid this week and go from there.

 

[aschumann28]

Water in the tranny. Flushed and filter change, no progress.
Lots of shimmer in the filter.

Took to a heavy equip mechanic, 6000 to install reman tranny..... Comes with 6 month warranty.

I can't really gauge if that's is high or not....spent 2500 on tranny in one of my trucks and that was from a shop I trust.

What are y'all thoughts?

Thanks

 

[Curbster]

Not sure if you have checked out these links here on the forum or not, but you may be able to get some decent information from some of these owners about parts and such. I will post them here and there may very well be more on site that I have not seen. Good Luck and let us know how you make out.
https://www.heavyequipmentforums.com/showthread.php?22956-Help-426-cat-tranny-problem
https://www.heavyequipmentforums.com/showthread.php?33033-Cat-426-backhoe-transmission-problems
https://www.heavyequipmentforums.com/showthread.php?15951-cat-426-drive-electric-solenoid
https://www.heavyequipmentforums.com/showthread.php?16698-426-cat-trans-rebuild-advice