If you have a temp gun it's pretty obvious, I think over 200 for extended times is to be avoided at any point during break-in. Yukon just says something like an hour or so to cool, I just stopped on the trip home and got lunch. It was plenty of time to cool down enough. I don't think you need a heat gun but it is helpful if you can't let it sit overnight between runs. The front diff doesn't see much load at all so it doesn't really matter in my opinion. My front ran slightly warm the first 30 miles but nothing that I'd need to let it cool for like the rear. What I've read is anytime you start loading the gears in a new way like towing it shifts the pattern slightly and you should allow it to cool off after a bit of use. Off road for the first time in 4wd I'll probably stop after a bit just to make sure everything is okay and running at a reasonable temperature.
75-140 Synthetic
- Thread starter notnsuv
- Start date
An IR temperature gun aimed at the cover or housing will only read the actual temperature of the gears if the gear lube is a conventional. Synthetic gear lube has a surprising trait of insulating the gears so the actual temperature of the gears will be significantly hotter than what the temp of the cover shows. That's why gears lubed with a synthetic run hotter during the break-in, it doesn't extract the heat out as well as a conventional gear lube does.
Just do the break-in per the instructions at https://www.revolutiongear.com/ring_and_pinion_break_procedure
Just do the break-in per the instructions at https://www.revolutiongear.com/ring_and_pinion_break_procedure
If you insist, but I personally don't see the benefits of a synthetic gear lube in an axle. There are some good reasons why well-known axle builders like Currie and Dynatrac changed their requirements to insist on the use of conventional gear lubes to keep their warranties in effect.
Did you record the temps of your housing during break-in? It would be interesting to have numbers for a set that didn't survive.
Nope, and I probably should have. For those wondering, I installed a set of new gears several years ago and against my better judgement I went along with a strong push/recommendation/insistance to use a synthetic since my axles were Rubicon Dana 44 and it was insisted there was some special gear lube flow reason for it. The rear gears didn't survive, they started howling during the first trip after the break-in process.
When the regearing guru (recommended by Revolution Gear) I went to got the rear gears out, he was pretty pissed and accused me of having used a synthetic during the break-in. He was right of course. He showed me the gears and said while the pattern was good they indicated having been overheated during the break-in. He installed the replacement gears and filled it with a conventional gear lube and sent me on my way for another break-in. I immediately switched my front axle to a conventional too. No more problems after that.
Although the situation sucked I'm glad you originally posted about it. Before I really thought it was just a typical synthetic/conventional discussion which it isn't and that really drove it home, at least for me.
I like them. I didn't mention it to my installer and he threw them away. I just put another one on the front while I had it open to install the lunchbox locker.
There are a few reports around here of people having trouble with them leaking on front diffs. I don't know if a strike to the cover breaks the seal and starts a leak, or if a strike to the cover causes an imperfection in the surface that won't seal. My first one was seeping a bit, but this time I just used a scraper to clean it and omitted the wire brush, so there was rtv remaining in the low spots on the housing, and used a different cover that had as perfect a gasket surface as I've seen on a 33 year old diff cover (it's for a High pinion and has a 1988 date stamp).
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