Diff oil cooler?
 

well i just put together an 8.8 with 4.10 gears and a locker but it seems that it get pretty warm compared to my old 373s. i was thinking of getting some kind of oil cooler for the diff fluid but the pumps i found around on the internet are expencive. just wanted to pick some brains around here for what i could use as an electric pump that could run constanly and move the 80 90 weight. i have a holly red fuel pump but am almost positve that it would not like that thick of fluid. i mainly just dont want to blow this thing up because im still gonna be doing some long trips with this truck a few times a year. any ideas appreciated

Gear oil gets very thin (fluid) when it gets warm/hot. You might try adding a temp sensor to the differential and either manually or wire it to automatically, turn on the pump once a specified temperature is reached.

OR put on an oversized diff.cover
(Ford : Mag-Hytec) and fill with a good synthetic gear oil.

Good luck

Were they NEW gears?

i almost promise that something went wrong during installation light duty vehicle diffs do not ever get hot enough to require a cooler when they are properly installed/maintained... even big rig diffs do not have coolers...they get friggin hot about 3-5 times hotter than the typical light duty diff on average but they do not need coolers...with 80-90 you should be able to drive till the engine is up to temp and then feel the diff and not be able to feel any heat if you can soemthing is wrong...i can drive half hour and i guarantee my diff would be luke warm at best

Only things that need differential coolers are some race cars.

it has new gears in it and is within all specs when put together. it dosnt get that hot and is only warm after a maybe ten mile drive but after a little highway drving like twenty miles or so it is pretty warm. how hot should they get anyway? never paid any attention to my old axle. just figured 410s ran hotter in 8.8s cause i looked under a lightning for sail near me and the housing actually had more cooling fins cast into the housing. dont know if that is some kinda aftermarket housing but they definatly wernt just welded on. but it dosent make any noise other than the standard clicking of the locker

If it's not making noise, I'd just leave it alone.

If you can still put your hands on the diff after a drive... you're fine.

I went camping once, around 60 km up a mountain, blew a tire 3 minutes into the drive back down and lost the tire. I drove down the road the rest of the way, knowing my friend at the bottom of the road had extra tires. When I got to the bottom, I saw steam coming from the diff. I first put my hand beside it, feeling some good heat. Tried touching it, and left a good red mark on my hand for a couple days.

I think that's when my RABS sensor failed, and never bothered to fix it.

mine gets pretty warm maybe even a little hot, but not HOT, but is a 10.25, I really kept a close eye on it because it was a junkyard axle and i wasnt sure of its condition, even though i checked the gears and they were still the original Ford 3.55's. Its been several thousand miles and it never had an issue. I figure the modded engines put tons more power and abuse through the 8.8's with out issues. I only swapped to a 1 ton for the weight carrying ability. I didnt like the look alot of weight on a semi-float.

The only issue is if the gears got set up badly. Or weren't broke in right. And i could imagine that the axle might be warmer if you still in the break in period.

then i just wont worry about it then because it is not hot just pretty warm but it dosent leave marks on my hnds when i touch it

then i just wont worry about it then because it is not hot just pretty warm but it dosent leave marks on my hnds when i touch it. and it has maybe 200 miles on it now so it is still in the breakin period of 500 miles. i was planning on draining all the oil out at about 1000 anyway and filling it up with some good synthetic. any thoughts on some good oil?