[gigem75]

After a sprited drive down the interstate at around 80 for about 40 miles, medium hot day I get home and touch the dif housing. Pretty hot, to hot to touch. I realize the middle muffler is right in front of it and there's a lot going on in there but was wondering how hot they run. No noise at any speed, silky smooth, no vibration, just pretty hot to the touch. Not hot enought to sizzle spit by any means but to hot to touch. Am I being over paranoid or does this sound like a problem? It's weird in all the years I've owned and driven Alfas I've never paid much attention to the differential/how hot it gets except to replace the occasional seal or rear bearing which I have to say is probably the harded job to do on a shrink ring retained Alfa wheel bearing if you don't have the right tool. Thanks!

 

[69alfa]

There is a lot of wasted energy from all the gears and it is given off as heat.

I just looked at a bunch of off-road truck sites and they all say if you can hold your hand on the diff it's ok. One said 130 deg f is normal .

Just read that limited slip diffs make more heat . Makes sense .

 

[gigem75]

Thanks, if anyone rips down the highway (like that's not gonna happen ) could you reach under there and give yours a touch and see if you can keep your hand on it, no torture please.

 

[roy]

After a long drive , rear is too hot to keep my hand on , running Redline synthetic oil .

 

[gigem75]

Thanks, after some searching it appears that they run around 140 which is the temp in the average hot water heater and I sure as heck can't keep my hand under that! The reason for this little (ha) project was that I was getting not metal dust on the magnet but some metal shavings and a stick on the dif housing was giving me some scary noise. It was a 410 rear end I'd gotten a couple of years ago. Found another one out of a 94 spider and put that in and replaced the wheel bearings and all three seals. The wheel bearings were not what one would get from your big two but rather some really nice solid looking made in the USA SKF bearings. It was a low milage 94 rear axle and this is the quietest the car has ever run so although it was a big job it was worth it.
Fortunatly being the pack rat I am I had a length of schedule 40 inch and a quarter pipe I was able to cut to the right length to press the bearings and heated retaining rings onto the axle with my el cheapo HF press. Getting them off is the hard part. I did write down the numbers on the SKF wheel bearings and will pass that info along for anyone who wants it:
SKF BB1B-630560D USA 1400 213E
Today is a good day! that's all I'll say about that here