Fluctuating Trans fluid level on 4300

[tim_s]

I been having a weird problem with my 4300 trans fluid level. This is a 2wd, SST, 420 FEL. When I walk out to the machine (it has been sitting overnite say), there is no oil visible in the veiwing hole, or window. I know it has oil as I have put 7 gallons in it. There is no tell-tale evidence of leaking oil anywhere. I can start it and run the FEL up and down, no change. However, if I then drive it aroud some, the indicator shows to be overfull. What I mean is the level is supposed to be halfway up the window, and it is all the way to the top. It may be something I have done, but I'm not sure what. I changed the trans fluid, filter, and suction screen this spring. I put 6.3 gallons back into it, per the book. The level looked fine. I have since added the rest of the partial gallon, for a total of 7 gals, trying to get the at rest (and cooled down) level to halfway up the indicator. Everything is functioning fine, but this is really bugging me. If anyone has any ideas or experience with this please let me know.

Thanks
Tim S.

 

[WCarlson]

tim_s,
The operator's manual on my 4200 says to check the transmission fluid only after the tractor has been parked for at least one hour. If I let mine sit for that long, or over night, I get an accurate reading. If I run it and then check, it appears to be overfull. Suggest that you let it sit overnight, then fill it to the halfway point on the glass. Then check it again the next morning and each morning prior to starting. When I last changed mine, it took nearly a gallon more than the specified "approximately 6.8 gal" to get it halfway on the sight glass.
Bill

 

[jrlichina]

As the fluid heats up it expands, example: that's why for automatic transmissions or power steering pumps there is a cold fill line and a hot fill line. The Hot line is always higher on the stick(due to expansion). Your HST is just a big hydraulic pump and motor. Just check it at the proper temperature, sounds like you're Ok.

 

[Wildman1]

Also, make sure you relieve all hydraulic pressure to the system by dropping the FEL and 3ph. That returns fluid to the transmission.

 

[yellowsocks93]

I also thought the sight glass on my 4300 was weird. When I let mine sit overnight, the sight glass would be full of oil but when running the level would drop to low. But on my new 990 the level stays the same no matter what. 3pt up or down no difference in oil level. If the tractor has been running for a while the oil level is not that much higher only a couple of centimeters.