Hydro with Hydraulic Lift Flush

[71_Bronco 1,072]

Right now, Im working on the engine for my Bronco 14, and sometime in the near future will be the trans. I have the stock hydro trans, with hydraulic lift cylinder / lever.

 

I want to flush the trans out and put in new fluid. I've read about using diesel fuel / kerosene to flush transmissions before.

 

My question though, is will this type of flush hurt the lift cylinder at all? Or will it not even flush the lines? Should I remove the lift cylinder assembly and plug the holes while I do the flush so the hydraulics aren't affected?

 

Thanks

[daveoman1966 3,762]

I own...since 1973...the same Bronco 14.  It uses ATF and I always use top-end ATF to keep it full as it drips a bit at the hyd cylinder.  You can change the fluid, but there is ...IMHO...no need to do a diesel flush or, at least I've never found the need.  All I'd do is change the oil and NEW FILTER.  Do NOT run the trans to "Make sure I get it All".. That causes lots of parts to run with dry contact, potentially damaging internal brass parts.  Just drain the fluid and change just as if it was you car / truck oil change.   

[pfrederi 17,885]

If your hydro fluid is so dirty  you think it needs flushing you have big problems. i doubt it would work very well at all.  Like Dave says just drain it and refill it with what ever was in there  (Red is ATF most likely)  some were changed to motor oil tan..unlikely... and a new filter.

[71_Bronco 1,072]

I don't know if my trans NEEDS a flush, just figured it would be a good idea since it was off the tractor and I could do it.

[daveoman1966 3,762]

An added comment:  ANYTIME and EVERY TIME you refill or 'top off' the fluid level, be CERTAIN to wipe off the filler tube BEFORE pouring in new fluid.  Wipe off the tube, wipe the funnel clean, as well as the pour spout of the oil container.  These Sundstrand Hydro-gear units are extremely susceptible to the slightest little bit of debris that will scar damage the relatively soft BRASS internal parts.  When that happens, you'll get to rebuild the hydro pump.  With proper care, they'll last for decades....mine is a 1972 model and never had an issue with it, except for the drippy cylinder.

 

Edited October 5, 2018 by daveoman1966