Differential heater
 

I was curious as to how other fellow racers have installed a heater in the differentials.
Of course an obvious option is on the exterior of the housing...but does the heat actually penetrate the thick iron of the center section?
Is putting the pad inside the center section a good option with all the moving parts inside?
or would a block heater type element be the way to go?

The differential for my application is a 12 bolt chevy with a LPW cover if that matters at all

Re: Differential heater
 

I just slide a 500w light under the rear diff. About 30 min and she is about as hot as I dare get it. I only do this for class eliminations. What's it worth? Not as much as you hope!

Re: Differential heater
 

I use a immersion cartridge heater screwed into the drain plug

http://www.mcmaster.com/#cartridge-heaters/=qofs8g

Re: Differential heater
 

Yeah I realize that, just dreaming out loud as I was servicing my differential. Had a discussion about lubrications the other day and just got the brain matter flowing is all. At any rate something is better than nothing...right?

Re: Differential heater
 

have heated the gear oil several times never saw a thing out of it
so we just use the good gear oil and that does the trick

Re: Differential heater
 

My friend's recently sold Pro Stocker had an oil tank/pan heater screwed into a welded-in bung in the back of the rear end housing. The cord was zip-tied to the left wheelie bar so it was easy to plug in to warm up the gear lube before each round. I thought about adding one to mine. Easy to weld the bung to the rear cover of my 12 bolt. Just use it for tough heads ups, class, etc.

Heard of guys running Dexron ATF for gear lube (One guy said "all the time"). Not sure about that deal. I'm too old to weld up the gears in the lights and go for a ride. LOL

Re: Differential heater
 

Ed' I have used atf a lot in slow cars and never hurt the gears.

Re: Differential heater
 

Use a light weight synthetic rear gear lube. :)

Jeff

Re: Differential heater
 

This is the stuff that I was envisioning, "outside of the box" keep it coming

Re: Differential heater
 

Good reference point - FWD cars use ATF to lube the differential......

Re: Differential heater
 

For that matter you could probably completely drain the rear-end for one pass without damage.

Re: Differential heater
 

I helped on a Comp car years ago, where ATF was tried in the diff.
It ran E/SM at the time (old format) and right on the record.
It was losing nearly .10 each pass.
After 3 qualifying attempts, we could hardly push the car.
Tore it up pretty good...
Used gear oil from then on.

Re: Differential heater
 

That ^^^^ doesn't really surprise me. I never had the nerve to try it. I appreciate hearing that. The guy talking about running it all the time has a slow et bracket car. Like 13 seconds. He never mentiond testing it, he was just sure it had to be "worth something".

I ran it half full of gear lube for a couple of weeks. (Listening to the wrong guy) I had changed something else at the same time (should know better by now) When I filled it back up I picked up a good half a MPH with it topped off.

Re: Differential heater
 

Run Joe Gibbs qualifying oil,you don't need a heater with it. gsa612

Re: Differential heater
 

Wonder if anybody has tested that stuff?

Re: Differential heater
 

A few years back I went to a T&T, drained out the RP and put in the JG.My buddy brought his car we made a pass together he lost a hun.from his previous run (DA was the same) and I picked up 2.I left it in for another few races. I know some guys run it in B&C cars (12 bolt).Mine is a 10 bolt btw. gsa612

Re: Differential heater
 

I tried some stuff that looked like atf. The guy I got it from said comp and prostock guys used it. It wore out the ring gear in about 6 runs. It didn't break, it just wore down the teeth. I love superlight gear lube, but this stuff did not work for me. The redline superlight weight is great and I never had an issue with parts wear. I would think the gibbs stuff would be similar, but I have not tried that. Our car was a 2900lb stick stocker Nova.

Re: Differential heater
 

The discussion that prompted this thread was around gear and transmission oils. The JG qualifier, and the ATI (also JG) and the properties were the focus and the pro's and con's of heat put to them. I guess the qualifier rear lube doesn't really like too much heat put to it ,somewhere around 160 degrees or so, and some of these heating pads and elements go way above that. The synthetic trans oil apparently works the same cold or hot so that is a push.

As I was working on my diff ,I was curious just how a measureable amount of heat could be applied and if it was worth it. I have heard about the ATF in the diff before but no evidence of any good qualities of using it, I assumed the gears would be sacrificed, as rear drive diffs weren't designed for that type of lube.

PS thanx for the pm's some really great ideas out there, I love the outside of the box thinking

Re: Differential heater
 

Dion,

There are a few issues with this conversation. First off you really cannot take anyone’s advice on what to use in your combo unless they have the exact same combo right down to surface treatment on the gears. Where ATF may be the best choice for lets say a 4 cyl FWD 200 horsepower stocker its certainly not a good choice for some blown 900 horsepower new stocker. Its all about the pressure and surface speed on the gear faces. Best thing you can do is just try a few different oils and figure out whats best for your circumstances. You do not even have to rely on a time slip to do this. Just measure the differential temperature before and after a run. You can use a heat gun or a more accurate measurement can be taken but using an eye type thermocouple under one of your cover bolts. The fluid that causes the lowest temperature rise in a run is what’s best.
For those that want to use a heater it can easily be temperature controlled with the thermocouple under one of the cover bolts and a digital control. For me this is what I used to do when I ran 75 weight oil. The last couple years I have been running the Red Line super light and have no need to heat it

Re: Differential heater
 

Bill I know of some 1400 HP FWD cars that use ATF in their differentials They have a 170 plus trap speed.
Could be the gears are cut differently (Not Hypoid?). But they use it I know.

Re: Differential heater
 

Think load from car weight could be part of it too?

Re: Differential heater
 

Yes, just equates back to pressure on the gear face. And what Art mentioned how the gears are cut can affect both how much the gears must actually slide against each other and the actual amount of contact area they have. As for a 1400 hp FWD car using ATF could it be due to necessity as the transmission and differential share the same oil?

Re: Differential heater
 

Ed I'm pretty sure the way the gears are cut for a RWD application is the difference. Our ring and pinions make contact in a completely different area.

Re: Differential heater
 

Yes they share the same oil.

Re: Differential heater
 

I have a bunch of free Valvoline 75/140 synthetic gear lube that I would like to try. We have a Dana 60 and have had 0 problems in 9 years of hard racing so I'm afraid to change anything. What do you guys think? Just looking for consistency. We now use 80/90 conventional.

Re: Differential heater
 

gsa, which JG oil were you using for your differential? I was looking at their website and they list the L9 thru L11, the L11 being their qualifying oil which they say can be used for short periods of time.

Re: Differential heater
 

I use it in my Dana and the gears last literally for ever. I am sure I get way over 1000 runs and have never had one fail with the auto trans. I did try some lighter oil and the gear wore out fast. No improvement in ET with the lighter oil so I went back to the Valvoline synthetic.

Re: Differential heater
 

I don't know if what I do works or not, but it makes me feel good about it. Here goes. I run 1\2 quart synthetic auto trans fluid, 1\2 quart 50 wt. synthetic racing motor oil, and 1 quart synthetic 80\90 gear lube. We put over 100 runs on a 6.20 gear before changing gears. Mostly 1\8th mile. A stick car leaving at 9,200, weighing 3040 lbs. The only thing I see that's changed is we used to get about 150, to 170 runs on a nodular center section then an aluminum through bolt. Anyone ran into that? Makes me wonder if the nodular might actually take less drag because of distortion. I never run it low.