So they finally cracked and I need to replace them with the aluminum ones. However, its my 1st nitro and I can count how many times I drove it still. Is this a difficult replacement? I know I won't learn till I do or try it, but for all the people that have done this before, should someone who is still very new to nitros and nitro wrenching, try to replace a diff himself, or wait to learn on something less difficult.

1-10 with 10 being the hardest, i rate that job about a 2. If that. Its seriously that simple.

This is a very simple repair, due to the trucks design more than anything.

You'll need to remove the screws holding on the front bumper plate as well as two more underneath holding the bumper on. Pull this plate (and bumper) off along with the aluminum behind it and you'll have direct access to the diffs. Pull the two small spacer blocks out and remove the diff case completely by grabbing the silver CVD's on either side and pull straight out.

Don't be afraid to yank on the diff, there is nothing else holding it in but friction of sand, dirt and a buildup of grime. With the differential removed you can unscrew the broken case (4 screws) and place the inner diff into the new metal case along with the drive-shaft. Apply a bit of white lithium grease to the inside of this new metal case and bolt it together.

Because the metal cases don't mark which side is up you'll need to put it side by side with the original plastic case to figure out which side is up. Slide it into the carrying tracks and insert the CVDs from the wheels to each side of the diff. Remember to align the driveshaft into its yoke underneath the truck when pushing the differential in as well. Gently roll the truck forwards to ensure you installed the diff in the correct way. If it won't roll chances are it's in upside down. Remember to put the black spacers in and finally align and bolt the bumper plate back onto the kingpins.

It sounds more complex than it is really, the trickiest part is making sure to align up the driveshaft underneath the truck as well as the two CVD's to each wheel when reinstalling. I had to replace a plastic case with a metal one last weekend and the entire process took me 5 minutes per diff and I made it in time for the next heat of the race. I guess this is why Losi made the differentials easy to access.

....and when you replace the rear diff, don't bother taking off the tie rods. Just remove the aluminum plate/bumper and move it up out of the way. Remove the 2 spacer blocks and pull the diff out.

make sure to take off the lower shocks when doing the front. My alum diff cases said top, they were the Team Losi blue ones.

there's no need to take off the shocks when doing the front...or at least I never had issues.

Uh! i had to move my shocks out of the way to pull the front diff, because the drive shafts would hit the shocks and not allow the diff to pull all the way out! I dont know how you got it out. And i would rate it pretty easy, and while you have the diffs out switch to diff oil, seems to work alot better than grease. (neewbie's 2 cents)

You cannot slide the diff out without taking the bottom shock mount off. I am sure you have done this before!!

Ah, I had to double check by testing on my truck this afternoon and I simply pull a kingpin for one of the A-arms allowing you plenty of room to pull the diff out. I find it easier to remove and replace a pin than a screw and nut.

There is no nut on the shock screw just a 3/32 hex head screw.

I also just pull out the lower hinge pins. They are right there, all you do is pull. It's the easiest method.

I did the same thing as jefx, its easier and faster

12 screws to remove the front and back bumper guards and you will have easy access to pull out the diffs. It was my first time, and looking at the book scared the heck out of me. But doing one I was thinking WOW this is super easy. Are you going to leave grease in the diffs or going with silicon? If you go silicon a decent weight is 30k front and back. Dont forget to get new rubber gaskets or you may have some leak problems. I bought them off the mugen shelf. They have something like 12 in a pack. If you do silicon, make sure you also clean out all the grease. Nitro engine cleaner worked well and a bunch of paper towels for me....

I'm gonna use silicon, probably the same weight you suggested. I won't get a chance to do it till later this week. I had to order them from the hobby store, and they won't get here till Friday, which of course is the day I'm leaving out of town. Hard to believe its that easy. Is there anything else that I should know? Is there a certain kind of rubber gasket that I should use when I put the new ones together? Haven't seen the inside of the diffs yet, will there be a problem put the gears back into the new one? I know its not as serious as the trans, but still.

Naw, it's about as basic as a rock fight.
You should have no troubles.

Look at your LST operation guide page 8. You will see: IMPORTANT: Always reinstall...... That part you see is only a gasket. Mugen sell them by the pack. Everytiime to take the diffs apart you may want to replace it. So look for Mugen seiki parst and find the differental gaskets. If you buy from Losi you will have to buy the whole rebuild kit, which is nuts. Buy the pack of gaskets from mugen allows you to take the diffs apart and try different weights on the diff oil.

Just out of curiosity, how many people actualy replace the gaskets everytime they open the diff? I just use them until they become ripped or something.

Ditto! ain't broke don't fix it!

If you were to work on your car, replacing a oil pan, tranny,diffs, heads etc and pulled the gasket off would you not replace it??? Even if it didnt seem to have anything wrong. I would. I realize this aint a car but same principal would apply. Also going from grease to silicon you want to make sure to clean all the grease out, including the grease off this gasket. Besides mugen seiki comes with the same size gasket with about 10-12 gaskets for about 4 bucks. Holes match up too.

I'm not saying that changing the gasket is a bad idea. I just honestly want to know how many people actualy do it?

Of course I'd change the gasket on a real car. But there's a big difference between the side affects of destroying the engine in a vehicle worth tens of thousands of dollars, not being able to get to work, and then paying for repairs..........As opposed to possibly having some diff oil leakage in my toy truck that I might have to eventually re-fill.

For me, my LHS doesn't deal Mugen Seiki parts or cars. So I just reuse a gasket untill it becomes too physically worn to work properly.

Guys,
Correct me if I'm wrong but I recently changed my diffs to the aluminum ones and found a single shim on one side of each diff case. The thing was that I had to place the shim on the opposite side of the case when using the aluminum as compared to the plastic one. I made the mistake of putting it back together without changing sides only to find the meshing of gears extremely harsh. The tip to change the shim to the other side came from someone on this forum. Know works like a charm.

Ya, that's pretty much standard with the aluminum cases. A few people have even had to remove the shim completely.

I just upgraded to the aluminum differential cases before I ever started the truck. The stock cases, as well as the aluminum ones have 3 screws in them, not the 4 that was mentioned earlier.
I pulled the 2 bottom king pins to allow the A-arms to pull the wheels out of the differentials, I also removed the skid plates. I guess I should have read this earlier. O-well, I learned more about the truck then I would have, if I hadn't taken it apart as much. Not a bad job. I was a mechanic of diesels for 6 years in the Army, those tanks and trucks were a tad bit bigger then these things

I agree with you, when I did my upgrade, I removed half the case, and placed the aluminum half in place, flipped the case over, and did the same on the second hald. I didn't touch the grease or gears. My situatition is a little different because I have not run the truck yet. But I don't see why the gasket would need replaced just because the differential case was opened up. The gasket is in between the gears.

Now if you were playing in the mud and water, and the differential case got busted, Then yes, replace the gasket, clean the gears, then use clean new grease, and a new gasket. Nowhere does it state to use a new gasket, just that you must allways reinstall it. The way I read it, is you use the same one, after all it is rubber, and should last a very long time.

Lex...Saw your comment on putting the shim on the opposite side of the aluminum case on reassembly. I have not seen anyone else mention this and was wondering if this is required? I am ready to put alum cases in soon and want to get all the facts straight before hand. Also what do you use to clean the grease out as I will use silicone fluid on reassembly. Thanks much.