Jrain 276 #1 Posted June 17, 2021 Need help Again on my new project c120 , I have read that around mid 1973 the hydro trans fluid was changed to use 10/30 motor oil , The fluid in it now is transmission fluid , I do not know the history of the tractor or the PO being I saved it from a scrap pile that was going to be cut up a few weeks ago , I believe the tractor to be around 1974 this is going by the Kohler engine ID plate (K301s ) 47421D ./ The ID plate on the tractor reads 512-10 / 939473 ,but with no real history I want to make sure it has the correct OIL/fluid in the trans and replace it along with a new filter. being I have it up and running now and I am slowly going over the entire tractor correcting ,fixing or replacing all parts that are worn before I start using it . 1 Share this post Link to post Share on other sites
Achto 27,751 #2 Posted June 17, 2021 12 minutes ago, Jrain said: The fluid in it now is transmission fluid Unless you are going to disassemble the transmission and completely clean it, I would suggest sticking with the ATF. Better option than mixing fluids. 3 Share this post Link to post Share on other sites
Jrain 276 #3 Posted June 17, 2021 I do understand that and would not have any reservations tearing it down to clean if the ATF that is in it now does not belong in it , So what you are saying is if this Transmission is not a ATF spec it is ok to have ATF in it with out having issues 1 Share this post Link to post Share on other sites
roadapples 6,983 #4 Posted June 17, 2021 Yes, either is fine. Stick to what's in it. 4 Share this post Link to post Share on other sites
kpinnc 12,426 #5 Posted June 17, 2021 So long as the tranny is strong, ATF is the best option. Keep regular maintenance up on it and always change the filter when you change fluid. ATF keeps these hydros cleaner than anything I have ever seen. I wouldn't change over to 30w unless the tranny is weaker when hot. Oil is a little thicker, so it might increase pressure in a weaker tranny for just a little while. 4 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,095 #6 Posted June 17, 2021 6 hours ago, Jrain said: Need help Again on my new project c120. I believe the tractor to be around 1974 this is going by the Kohler engine ID plate (K301s ) 47421D ./ The ID plate on the tractor reads 512-10 / 939473 ,but with no real history I want to make sure it has the correct OIL/fluid in the trans and replace it along with a new filter. being I have it up and running now and I am slowly going over the entire tractor correcting ,fixing or replacing all parts that are worn before I start using it . Do you have a 48" side discharge mower deck? 5-1210 is the model number for a 1973-74 deck. If the 5-1210 is followed by a -8 it is a 1973 model and by a -9 it is 1974. Garry 3 Share this post Link to post Share on other sites
Jrain 276 #7 Posted June 17, 2021 Thanks once again for the help and information , So ok will keep it ATF also have new Wix 51410 filter to replace ,No problems with the transmission seems to pull very strong ,The fluid looks very clean but I will be changing ATF and filter as I said I do not know the history of the tractor . Yes the ID on the tractor reads 512-10 and yes did not see the -8 and yes side discharge mower deck and I do think it is a 48 inch deck comparing it to my 38 inch deck on my 212-5 , So now I know for sure it is a 1973 . Again thanks you guys are great . 3 Share this post Link to post Share on other sites
gwest_ca-(File Mod) 11,095 #8 Posted June 18, 2021 2 Share this post Link to post Share on other sites
Lee1977 6,777 #9 Posted June 23, 2021 It could have been bought with a 1974 tractor and a 1973 48" deck. You bought the tractor and chose the size deck you wanted. The dealer could easily have had new 1973 decks on hand. 1 Share this post Link to post Share on other sites
kpinnc 12,426 #10 Posted June 23, 2021 1 hour ago, Lee1977 said: The dealer could easily have had new 1973 decks on hand. Good point Lee. Most people don't realize the majority of WH tractors came without any attachments from the factory. Decks were just the most common thing added at the dealerships. 1 Share this post Link to post Share on other sites
Jrain 276 #11 Posted June 26, 2021 On 6/23/2021 at 1:55 AM, kpinnc said: Good point Lee. Most people don't realize the majority of WH tractors came without any attachments from the factory. Decks were just the most common thing added at the dealerships. Yep Agree , like most people Don't realize that a car or truck rear view mirror, back in my day was a option that had to be ordered. and the windshield mounted mirror was the most common thing added , Share this post Link to post Share on other sites
