Gears & Axles - rear differential is hot
After a spirited drive of my car, my dad comes home and says something isn't right. I figured he messed something up again. :cry:
He said the rear didn't smell right. I got down there and felt it, and it was so hot I could barely touch it. The car smelt like a car that's been driven hard for a little while, I didn't know what he was getting at.
I just had 4.11 gears installed less than 1000 miles ago. I know the rear isn't leaking fluid, but I guess I'll check it anyways. There's obviously a lot of friction in the rear, but should it make the differential that hot? :confused:
The differentials obviously get extremely hard. You can't possibly think that it will be nice and cool? With the gears turning at obvious high rates?
And yes it will get that hot. Ever tried touching your block after a drive? I did and I got a nice bubble on my finger. After that I don't touch any mechanical components on my car for a good few hours.
06-23-2003, 10:00 PM
They will get very hot. And, if you hit the track and drive about 150 mph for 20-30 minutes, you will likely burn up a rear with 4.10's in it (due to extreme heat). Redline or Mobile 1 (synthetic) gear oil will help reduce rear end temps. I ran 130-145mph for 15 miles one night (many years ago, no traffic, in the middle of nowhere, racing another 89 Formula with my 89 Formula....I'm older now....but anyway) and the next day, I started haring strange noises from the rear axle. There were 8 teeth gone from the ring gear, and 2 from the pinion and the chunks had broken the spider gears up slightly). This car was a 305 (TBI, no less) with a shift kit. I sure didn't break it on HP alone...It seems that it overheated, softened the gears and "died". So, they can get real hot, even too hot. I'd change the oil over to synthetic for starters.....likely be find for street/strip use after that.
06-24-2003, 02:18 PM
My 12 bolt gets hot. Its normal.
My friend just installed a oil cooler for his Z06 rear end and M6 tranny. Its a pump that pushes the fluid through two coolers. Pretty cool I thought.
06-24-2003, 04:23 PM
Can someone give me more info on a rear end cooler and how to set one up, possibly a parts list too.
Thanks for the reassurance. I figured it was nothing out of the ordinary, just wanted to make sure.
06-24-2003, 08:36 PM
For a rear end cooler, you will need a fluid pump. The Nascar boys use a belt driven one that runs off of the driveshaft (trick, light, and effecient), but I've only seen those setups for a ford 9".
You can buy a pump from Tilton that will handle hot gear oil or trans oil. They are $199 from truchoice performance (www.truchoice.com) and you will need:
2. Braided line (#8 or #10 AN line)
3. Fittings for the rear (if you use a TA performance rear cover, pull it from the drian hole and return it to the fill hole on the cover. You'll need the correct pipe thread fittings to fit the cover (pipe thread to AN adaptors).
4. Cooler (something with large oil passages and several passes or a mocal or similar professional oil cooler)
5. Fittings to adapt your an line to the cooler (if the cooler has pipe thread fittings, you'll need more fittings like the rear cover uses, if it is AN (likely #6, #8 or #10), I'd use the same size hose and fittings for the whole thing).
6. Extra fluid (to fill the pump and lines and keep the rear full.
7. A power feed, fuse and power relay to wire up the pump to the cars electrical system.
That's the basics.
06-24-2003, 08:40 PM
The pump is at the top of the page, shown here: