Losi 8 Diff Question
 

I have a Losi 8ight-E and the center diff gets extremely hot. Im new to the 1/8 buggies so I dont know if its normal or what. You can barely touch the outputs cause there so hot. Its about twice as hot as the motor gets. I just put new bearings on it and it got diff oil in it. The front and rear diffs dont get hot at all. Is this normal?

no...there is some extra friction going on, replacing the bearings would be a good start

I just put brand new ceramic bearings last night and it still gets hot.

take the motor out and see if it rolls back and forth without binding....and/or make sure you got the right sized bearings.....

It spins freely in the bearings with the motor off and the bearings are the right size. Its got me stumped.

There may be binding in the rear diff, which also may cause the center to unload to the front easier, causing excessive heat build up in the center. Check for binding in the rear aswell. If you still can't figure it out, what weight center diff oil are you using? Maybe increase that up 10k or so, or have a little throttle control to see if it is unloading that is causing the heat.

Couple of extra things to look for if it helps :mdr: I hope you find the problem.

remove and inspect the inside of the CD it may need some rebuilding or need more fluid

How do you know when it needs a rebuild? Everything looks fine on the inside and the diff oil is at the top of the spider gears. Not sure on what diff oil is in it. I probably need to get some and change it and try that.

Ill check that front and rear diffs for binding.

if the parts look warn replace them and tuen the shafts of the diff looking for any binding.

Nothing is worn out in the center diff and nothing binds in the front rear or center diff. Its all loose as a goose. Only thing I havent done is changed the diff oil. When I play with it and get on the gas it unloads the front end and balloons the front tires which is normal. It will also ride a wheelie out so the diff oil cant be too thin. If it was to thin would it cause it to heat up?

Are you using steel spur?

If you are its probably the friction there that heats it up, My gears easily reach 100C while motor is just at 40C

//Gutav

I got the same problem on my d8, i ran new d8 and with brushless 2650kv on 4s ,after few runs i cant even touch the shafts the front and the back i will check for align and do i need to change the fluid cause i ran brushless?
car runs amazing!!!

The same thing happens on my eight-e running a mmm/neu 1512 2.5D/f (2050kv) on 5s. Try 10k fluid and it should lower the temps a bit, but if your running the stock steel spur it will get warmer then usual since heat from the pinion coming from the motor transfers onto the center diff.

I run the losi smart diff now and it doesnt get as hot, it also eliminated the front tires from ballooning and it has better acceleration.

If the thicker fluid doesnt help try putting some grease into the drive cup where the cup and pins meet, it should reduce some friction that happens. Other then that you shouldnt have to worry to much about getting hot drive shafts.

Changed the fluid and it doesnt get nearly as hot now. Still gets warm but im also running a steel spur.

Good then thats normal, have fun with your 8ight now! :)