Heat from Drivetrain

Hello all, I have a (hopefully) easy question for you: how hot should the drivetrain get? I have a D18, T98, Warn OD, with adapter and PTO. The whole thing gets hot to the touch after several miles of harder driving, such as up hills, or at speeds over about 40. It still gets warm under lesser use, but not as much.

I have no way of knowing which unit causes the heat, or if it is all of them. I have a recently rebuilt D18, and the OD is one from Herm - remanufactured. The PTO is a Spicer unit, but since it isn't on when I'm driving, I'm sure that it has nothing to do with this. I have clean fluid in all the units, and the level is okay. I'm using Lucas and 90 weight mixed about 50/50. Sometimes the OD slips out of direct, but never out of overdrive.

I've just licensed this Jeep for the first time since "finishing" it, and really don't know if the heat is normal...hopefully it is. If it is okay, then I'll just move on - but I would really hate to burn the thing up after all the work I've put into it. Your thoughts are appreciated, as always.

 

how hot is it? if you splash water on it, does it bead and boil off?

some heat is normal, sounds like your oil is too thick (more like grease than oil). I run 85w140 with about a pint of lucas in it.

 

No, water would not bead up like it would on a stovetop. Though painful, I can touch it without getting burned. I would be burned if I left my hand there for a few seconds though.

I wondered if perhaps the oil was too thick. I like using a thick mixture, as it has nearly eliminated leaks from the D18. That made me happy. But the heat worried me enough to post the question. So long as I'm not going to do some kind of damage, I would prefer to just leave well enough alone. If I use thinner oil, I'll have those pesky leaks again. R)

 

If the oil is too thick it can't flow between the gears and shafts and what not, nor will it flow through the bearings properly to help pull the heat away from the moving/friction parts. Dump it and put the proper stuff in.

 

Wouldn't the heat make the gear lube thinner and not be an issue. I could see this being a problem in the winter with lower temps but not now. Just say'n.

 

Any chance the brake is dragging enough to generate heat (but not enough to smell). I know I've had wheel brakes do that.

 

It could but by the time the gear lube got thinner and worked its way in to where it needs to be the damage is already done. This is progressive with the heat and cold cycles of starting and driving and stopping and cooling.

 

I'm curious. Is there evidence or experience that indicates that 50% Lucas in a TCase is going to cause probs from lack of lube? 50% is what Lucas recommends. Are all of their recommendations dangerous/false? I'm assuming that 90 wt oil is fine as that's what my Mil manual states ... it's just that the Lucas @ 50% is bad??

 

I can't really say anything good or bad about Lucas as I don't use it, never have, and not likely to. Heard good an bad, just no personal experience. I use regular gear lube or whatever is called for by the manufacturer.
BlueComet made the comment that he added enough to make it thick enough to get rid of the oil leaks . IMHO that's too thick whatever the kind of additive you put in. If it's thick enough to stop oil leaks, then it's thick enough to not flow where it's supposed to.....

 

To answer Homebrew2's question, I do not think the e-brake is the culprit. It did seem to drag a bit in the beginning, but I suspect that was just the shoes seating themselves after reassembly. This seems to be more generalized.

I did follow the Lucasoil instructions with the 50/50 mix. I actually wanted to go thicker, due to the leaks, but refrained since I didn't want to overdo it.

I checked it today driving home from work, and it was barely warm - after about a mile and a half. But going into the mountains, or towing a light trailer will heat it.

Well, I guess I'm going to be draining and refilling with 90-weight. Thanks to all for the help and advice; if you want to find me in the wilderness, just follow the greasy trail....

 

Fair enough. I'm running ~1 pt in the TCase and ~1 pt in the tranny w/ 90 wt. No "excessive" heat. It's far from a "grease" consistancy. I'll double check pulling a hard grade when it gets back to 100°F but, as said, the recipe should only contribute to cooler conditions. I'll change fluids again soon and will do the same unless I find reason not to