Bleeding air out of hyro trans

[Danman 0]

I have 1973 automatic 14 with a sunstrand hydro trans.I was wondering if there is a way to make sure all the air is purged from the system.There is a lever on top of the pump for pushing and driving,was wondering if this was removed would that bleed any air trapped in the pump being on top at the highet point of the hydro system? Thanks in advanced for any info.

[TT-(Moderator) 1,162]

Are you experiencing problems or are you just concerned about air in the system after a fluid/filter change?

Since this is a "continuous loop" hydrostatic system supplied by a charge pump, all of the air should purge on its own. Removing the tow valve while the pump is turning will result in nothing more than a huge mess. :thumbs2:

[Danman 0]

The hydro system had auto trans fluid in it.I have no Idea when the guy I purchased it from last did maintenence.I have switched over to 10w30.I have also flushed the system 3 times with a total of almost 15 quarts of oil and 3 filters.Trans seems to whine a little bit more than it did before the change over.Thats why I asked.

[kpinnc 15,717]

The hydro system had auto trans fluid in it.I have no Idea when the guy I purchased it from last did maintenence.I have switched over to 10w30.I have also flushed the system 3 times with a total of almost 15 quarts of oil and 3 filters.Trans seems to whine a little bit more than it did before the change over.Thats why I asked.

They all whine a bit- some MUCH more than others. Short of being low in fluid, I can't think of a reason for more noise.

Was there a particular reason you had for changing it over to motor oil? It's not a requirement, though some folks have done it.