HOrnbrod Posted October 12, 2017 Share Posted October 12, 2017 Ever since changing the gear ratio on my Dana 44 rear diff a couple of years ago from 3.55 to 4.10, the gears whine when going around 35-55 MPH with just enough throttle to maintain that speed. Not a loud whine, just enough to be annoying. When accelerating or decelerating in this range the whine disappears. At speeds above or below 35-55 there was also no whine. After talking to experienced gearheads who change diff gears for a living, I attributed it to after market gears (Yukon) and the fact I was using "thick" gears so I could retain the old Trac-lok carrier. Recently I changed the diff cover, and when refilling the diff, I used non-synthetic HD Lucas 85W-140 diff oil with friction modifier for the Trac-lok instead of the el-cheapo break-in no-name 75W-90 oil with friction modifier that was in there before. The whine is now gone, nada, ancient history. I'm happy the whine is gone, but can't help wondering why. I guess because of the higher weight gear oil? Link to comment Share on other sites More sharing options...
Minuit Posted October 12, 2017 Share Posted October 12, 2017 Hm, this is very interesting. Both of my trucks have D35s that whine at those speeds, although I imagine that's because the bearings are all sloppy. I think I'll try this and report back. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 12, 2017 Author Share Posted October 12, 2017 1 hour ago, Minuit said: Hm, this is very interesting. Both of my trucks have D35s that whine at those speeds, although I imagine that's because the bearings are all sloppy. I think I'll try this and report back. Please do. Link to comment Share on other sites More sharing options...
DirtyComanche Posted October 12, 2017 Share Posted October 12, 2017 Yes, it's the thicker oil. Most likely at least. Being better oil probably doesn't hurt. I'm surprised you ran cheap oil. And then not switching to a synthetic? Even I run synthetic, and have you seen my garbage!? Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 12, 2017 Author Share Posted October 12, 2017 I don't use synthetic anything in anything Dirty, be it motorcycles, lawn mowers, chain saws, anything. It's not the cost; I just think a quality dino product does a better job. As long as it's changed when the mfg. recommends (or earlier) regularly. The cheap diff oil was just for break-in. Maybe I'm wrong, but I've never had a problem with dino lubrication ever. Link to comment Share on other sites More sharing options...
87MJTIM Posted October 12, 2017 Share Posted October 12, 2017 Would it work in a manual trans - AX15? Is it friendly to brass parts? The Lucas data sheet says "it exceeds all GL classifications." Whatever that means. Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 12, 2017 Share Posted October 12, 2017 I don't buy the thick gear as a cause for whine, not at all. In the next few weeks, or when I get around to it, I'll be pulling the rear axles for the brake swap, I'm anxious to see what my fluid looks like. As I have mentioned before I'm using a 50/50 of 40W and Lucas, ran it for two years, maybe better than 25K miles. Every time I mentioned Lucas I have gotten the slap down........hocus pokus snake oil and all that happy crap. So, I don't mention it anymore. Lucas is a good product. I expect my housing to be clean, fluids to be clear, odor free. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 12, 2017 Author Share Posted October 12, 2017 20 minutes ago, Jeep Driver said: I don't buy the thick gear as a cause for whine, not at all. That's not the topic of this post. The thick Lucas non-synthetic 85W-140 diff oil cured the diff whine. And yes, Lucas makes great products. I'd use their non-syn gear oil over any other, including the ridiculously expensive Royal Purple, Red Line, and the others. Been using Lucas products for fifty years. Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 12, 2017 Share Posted October 12, 2017 8 minutes ago, HOrnbrod said: That's not the topic of this post. The thick Lucas non-synthetic 85W-140 diff oil cured the diff whine. And yes, Lucas makes great products. Been using their stuff for fifty years. Ok, your topic, your post, you stated three possible reasons for the whine. Thick gear, Yukon gear, cheapo oil. I cannot speak to Yukon gears, never used them, however, you will find countless discussions of Yukon whine, across the board, regardless of make or model. Quote I'm happy the whine is gone, but can't help wondering why. I guess because of the higher weight gear oil? Sounds like you found the solution to Yukon whine. I don't think thick gears have anything to do with it. I thought I was on 'topic'. Link to comment Share on other sites More sharing options...
HOrnbrod Posted October 13, 2017 Author Share Posted October 13, 2017 One of the local gear guys who does regearing for most of the stock car racers in the area and has the best rep mentioned that thick gear sets have a tendency to whine. Same guy says if you can't get factory thick gear sets (Dana doesn't make them for a D44 in 4.10), Yukon gears are the next best option. Anyhow, the whine is gone since I changed the gear oil and I'm happy. Maybe any heavier 85W-140 or so gear oil might have done the same thing. Who knows? Link to comment Share on other sites More sharing options...
carnuck Posted October 13, 2017 Share Posted October 13, 2017 For the ax-15, go with Redline MTLSent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
DirtyComanche Posted October 13, 2017 Share Posted October 13, 2017 1 minute ago, 87MJTIM said: Would it work in a manual trans - AX15? Is it friendly to brass parts? The Lucas data sheet says "it exceeds all GL classifications." Whatever that means. I use the synthetic in my AX-15. It, like most modern GL-5 oils, do meet the GL-4 spec for sulfidation corrosion. Unfortunately the presence of high levels of phosphorous means it will eventually strip the synchros (I did not know this when I put it in). Should I be using it? Probably not. But I'm not a fan of putting motor oil in a tranny. I'll probably switch it to something else next time, I haven't decided what though (most of the better options aren't really available to me, and I'm not putting $$$ Amsoil in a transmission that's already mostly junk). Link to comment Share on other sites More sharing options...
gogmorgo Posted October 13, 2017 Share Posted October 13, 2017 I switched to royal purple's synchromax when I noticed my Lada's transmission wasn't shifting quite as nicely as I thought it should be. It worked a whole ton better than the air I drained out of it. Link to comment Share on other sites More sharing options...
carnuck Posted October 14, 2017 Share Posted October 14, 2017 I use the synthetic in my AX-15. It, like most modern GL-5 oils, do meet the GL-4 spec for sulfidation corrosion. Unfortunately the presence of high levels of phosphorous means it will eventually strip the synchros (I did not know this when I put it in). Should I be using it? Probably not. But I'm not a fan of putting motor oil in a tranny. I'll probably switch it to something else next time, I haven't decided what though (most of the better options aren't really available to me, and I'm not putting $$$ Amsoil in a transmission that's already mostly junk). Amsoil local to us isn’t much more expensive than any other synthetic unless you don’t account for it lasting twice as long as regular oils. Sent from my iPhone using Tapatalk Link to comment Share on other sites More sharing options...
DirtyComanche Posted October 14, 2017 Share Posted October 14, 2017 1 hour ago, carnuck said: Amsoil local to us isn’t much more expensive than any other synthetic unless you don’t account for it lasting twice as long as regular oils. Sent from my iPhone using Tapatalk The only dealer I know here is pricey, and I get a massive discount at one of the other parts houses, specifically including Lucas products. Link to comment Share on other sites More sharing options...
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