Lagersolut 661 #1 Posted May 6, 2023 I have 5 cast iron transmissions here -4 horse and one Troy built horse. I came across this issue between GL4 and GL5 oil, some are saying the GL5 has additives that are bad and break down soft yellow metals like brass or copper ( bushings/gears ). I just changed the oil in my Troy built horse noticed the original recommendation was GL4 . This older non additive GL4 oil is hard to find and not cheap . I just changed the tiller with Lucas 85/140 says exceeds GL5 specs. What are you opinions on GL5 breaking down soft metals in transmissions? To be honest I've never heard of this issue until this year and I'd bet all of mine have GL5 for 30 years ... Share this post Link to post Share on other sites
Sailman 1,291 #2 Posted May 6, 2023 I would be interested in the answer to your question too. I have a Troy Bilt Horse that needs transmission gear oil changed and had heard the same issue of newer gear oil being bad for the brass parts in the gear box. 1 Share this post Link to post Share on other sites
squonk 41,135 #3 Posted May 6, 2023 (edited) You won't find GL4 anymore unless you get it from some specialty co. $$$$ . Most WH transmissions have very little bronze/brass soft metal with the exception being the 3 piece 5003/5010's. You will be gone well before you will ever have to worry about it. Keep your oil clean and keep out the water and you'll be fine. Edited May 6, 2023 by squonk 3 Share this post Link to post Share on other sites
stevasaurus 22,758 #4 Posted May 6, 2023 The only bronze in any of the Wheel Horse manual 2 piece transmissions is the two bushings in the cluster gear. Like Squonk said...No worries, use the GL5. 2 Share this post Link to post Share on other sites
Lagersolut 661 #5 Posted May 6, 2023 1 minute ago, stevasaurus said: The only bronze in any of the Wheel Horse manual 2 piece transmissions is the two bushings in the cluster gear. Like Squonk said...No worries, use the GL5. This was more of a generalized question not really specific to WH - was reading some old literature and various places on the net seems some places it’s a real rabbit hole of debate . Like I said - never heard a thing about it until this year - 100% sure all my stuff has had GL5 for 30 years - including the Troy Horse with a brass gear . Like @squonk posted above I looked for it - 22-25 quart $$$$ 1 Share this post Link to post Share on other sites
rmaynard 15,498 #6 Posted May 6, 2023 When you consider that many transmissions on Wheel Horse tractors are running a mixture of 50/50 oil/water, it's safe to say that a good clean GL5 oil is going to do no more harm to yellow metals than the water is doing. Keep clean oil in the transmissions. Nothing in there is running at high speeds. Share this post Link to post Share on other sites
oliver2-44 9,756 #7 Posted May 7, 2023 We went through this question at the dams on some large gear boxes. Talked with Philips Lube Engineer/Chemist and he said the additives (sulfur) in GL5 would only be a problem in heavily loaded HIGH heat applications. While our WH transmissions might get warm, they are fine with GL5 1 Share this post Link to post Share on other sites
