312H Unidrive Case Temperature (Hot!)

[Mazdaprotege4 5]

Was mowing with the 312H last week and the mower felt slightly slower than usual.  When I got off the mower I checked the unidrive and it was really hot , couldn't touch it for more than two seconds.  Is this normal or does anyone have any insight as to why it would be hot ?  Thanks

[stevasaurus 22,883]

That is not normal.  No unusual noises??  Check the oil and see if it looks burnt...if it is that hot...it should show it. 

[elliot ness 1,916]

Not normal, should be worm, but not hot.

[Mazdaprotege4 5]

Checked the oil seems clean and not burnt (isn't that dark brown color).  As far noises I havent noticed anything out of the ordinary, but I will say that the ground was wet when I mowed (didn't have a choice as I wasn't going to be around for a week again to mow).  Would soggy ground cause that much more of a drag to heat things up?  Also I am probably due for a service on the transmission, what does everyone use for fluids? Thanks

[Ed Kennell 38,759]

Clean all the grass from the cooling fins and make sure the cooling fan is running.

[DougC 2,641]

   My '88 520H with dash hydro temp warning light would come on after about an hour of mowing this spring and temps were only in the mid 70's

I removed the seat and seat pan and just cleaned the dickens out of the hydro fins, body and everywhere for that matter and then washed it off with brake clean. There must have been five pounds of crud on the floor and now even with the temps in the 90's the temp light does not come on and the airflow coming out behind the hydro from the fan is 10 times what it was before the cleaning. I was lucky I had a warning light to tell me my hydro was in trouble.

[Mazdaprotege4 5]

Thanks guys, I am going to pull the seat pan as mentioned and give it a good clean and also change out the fluid since it has been a few years.  From what I have gathered, it just takes standard synthetic 10w-30 for the Eaton 11 trans/hydro assembly, correct?

[lynnmor 7,356]

I had the plastic fan come loose, on a 520H, and the trans got very hot.  With it just slipping, it still would spin of course but not reach full speed.  Unless the fan was checked by hand there was no evidence of a problem.  You may not have a plastic fan, but I wrote this to let everyone know the importance of the cooling fins and fan on these hydros.  I would never have believed that the temperature would climb as much as it did without having had that experience.

[roadapples 6,983]

  

[MalMac 1,331]

Yes, 10-30w synthetic is just fine.

[Mazdaprotege4 5]

Thanks everyone.  I think part of the problem was that it had the wrong filter (Napa 1307) so I put the Napa 1410 filter on.  Also the oil had seen better days so hopefully the synthetic 10w30 I have will make an improvement.  I was only able to use it for a few minutes but will get back out tonight and get some time on it to make sure the temps drop.  One weird thing that did happen when refilling it was that it only took 4qts of oil. I moved it back and forth in the garage for a second thinking it has to circulate but it was still full after that.  Is there really just that much oil in the system that's not in the case?  Thanks

[can whlvr 993]

yes some oil stays  in the system,its near impossible to get it all out

[shallowwatersailor 3,213]

6 hours ago, Mazdaprotege4 said:

Thanks everyone.  I think part of the problem was that it had the wrong filter (Napa 1307) so I put the Napa 1410 filter on.  Also the oil had seen better days so hopefully the synthetic 10w30 I have will make an improvement.  I was only able to use it for a few minutes but will get back out tonight and get some time on it to make sure the temps drop.  One weird thing that did happen when refilling it was that it only took 4qts of oil. I moved it back and forth in the garage for a second thinking it has to circulate but it was still full after that.  Is there really just that much oil in the system that's not in the case?  Thanks

 

Check it after driving it for more than just back and forth. Let it cool and you will find that it will be down probably at least 1/2 quart.

[Mazdaprotege4 5]

So I checked the level today and it was still full so that part is good.  But when I was mowing for the last 40 minutes or so the case was still hot.  I could maybe touch it for three seconds before I it got too hot to touch.  So far I have changed the fluid and filter and took the fender off and cleaning all of the cooling fins.  Is there anything else I should do or is this just something I shouldn't worry about.  Thanks again for everyone's help!

[can whlvr 993]

I geuss you just have to run her,mine gets pretty warm in the summer too,but she keeps on pullin

[Ed Kennell 38,759]

Still have not seen if you checked to see if the fan is running at speed.

[Mazdaprotege4 5]

Sorry, I forgot to add that, the fan seems to be putting out plenty of air, but I may replace the drive belt just to be safe.  Thanks for all the help everyone!