jonbar87

I was curious if the Mag-Hytec cover actually helped reduce diff temperatures so before I swapped to 4.56 Nitro gears, I purchased an infrared thermometer and recorded a few runs to work and back. I then did the same after installing the gears and new Mag-Hytec diff cover. Unfortunately, it wasn't a very scientific test because a lot of my variables weren't controlled, like the type of fluid and the gears. With that said, here is a comparison of the stock cover with stock 3.55 gears compared to Nitro 4.56 gears with a Mag-Hytec cover. I was very surprised to see that the diff temps actually INCREASED after the gear/cover install instead of decreased. That makes me believe that it's the lower gear ratio that are heating things up. I really wish I would have tested the cover before the gear change, but obviously it's too late now. Anyway, FWIW, here's the data:

KustomFX

iTrader: (3)

Very Interesting...
I read in one of your threads that the new gears were making noise, which is typical if not installed correctly and set up (shims, backlash, etc) is not done properly.
Have the noise gone away? does the company still say that it was normal and all of them make noise?
Is it possible that tolerances are just too "tight" which would also result in increased temp?

jonbar87

That's correct. I personally think the noise is not normal and that they are too tight, but the shop swears up and down it is normal. The higher temps make me even more suspicious, but my rear end hasn't exploded yet so maybe it's ok? Who knows

FX4362

Were you reading temps from the outside of the cover? The higher temps may mean it's working because it has the fins to pull out the heat from inside and dissipate it outside. I could be completely off base but it sounds plausible to me.

jonbar87

I was reading the outside of the cover both times. I could be wrong but I would think that thin of metal/aluminum would be the same temperature on both sides of the cover...

Z7What

How long of a drive and at what speeds did you travel? I have a Mag-Hytec cover on my stock 3.55s and could shoot mine for a comparison.

Wayne

DieselDawg

You could only really know if the temps of the fluid are lower by...wait for it...taking temps of the fluid itself. That being said...gears turning faster (3.55 vs 4.56) are going to create more heat and the same speed. I would at least try measuring at equal rpm runs to see if that gets the temps closer to equal...if there is a way to figure out what rpms you were running with 3.55's and stock cover.

jonbar87

All my runs have been to work and back, around 15 - 20 minutes @ 65ish MPH. I get out and measure the temps immediately after I pull into the parking lot and park. I point the infrared laser on the actual Mag-Hytec plate that is on the cover. My thermometer also locks in the highest recorded temp so I will move it all around the cover then use the highest temp it recorded but usually that plate is the highest temp.

RPMs aren't that much different...maybe 250 - 300 at most. I could be wrong but I'm thinking it's gotta have something to do with them being tighter...which would explain the noise they make.

DieselDawg

Those gears should make rpms differ by ~22%...so at 2400 rpm that would be 528 more rpm...at 2000rpm that would be 440 more rpm...1700 rpm would be 374 more. A bit more than 250-300. Now that is engine rpms more...but it translates to more work at the rear end too.

jonbar87

True. Most roads are 55 mph here so I was always around 1700ish before...now I'm like 2100ish so yeah, more like 400. But either way, it's not that much