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-   -   Diff rebuild question (https://www.rctech.net/forum/nitro-off-road/492663-diff-rebuild-question.html)

SDelaney 03-15-2011 04:53 PM

Diff rebuild question
 
Okay, I just rebuilt my front diff in my Losi 8T 2 and I used 7000 Associated Diff oil. This is all my LHS had, they were out of the Losi 7k weight so I picked the Associated stuff. Are these the same or should I have chose a different weight since I went with Associated?

Question 2: What does it mean when I spin the diff and you can feel the gears spinning on each other. Everything is back together how it is supposed to be, but I've never done this before so I am not sure if this is normal to feel this.

Thanks in advance

DiZzYNaTiOn 03-15-2011 05:07 PM

Question one, there pretty much the same you'll be fine

Question two, is it a grinding? They should be smooth. Move the wheels in opposite direction there should be no bumps.

rider313 03-15-2011 05:16 PM

Aslong as there is no binding or grinding you should be good on number 2. there is a losi 8ight T 2.0 thread. Post in there for any questions you have with your 2.0 instead of creating a whole new thread. We will be happy to help you in any way.

SDelaney 03-15-2011 05:29 PM

Ok, I will post there going forward... Its hard to explain the feeling, it doesn't bind but I can feel the gears spinning as I turn it. I wonder if it just has to do with the thicker fresh diff oil. Before it had just the stock fill from the 8T RTR kit.

All teh gears looked good when I cleaned it and they all seated properly when putting it back together.

rider313 03-15-2011 05:38 PM

Good deal. And what you are describing sounds like a normal diff with fresh fluid. :nod:

DiZzYNaTiOn 03-15-2011 05:52 PM

Wait, pick your rear-end or front (which ever one) up and grab both wheels, rotate tires in opposite directions,

Do you feel any vibrations or even the smallest amount of grinding?

If so you need to check it out now before you drive it and blow out a diff.

SDelaney 03-15-2011 07:19 PM

I haven't gotten it all back together yet, but I will do this tomorrow when I put it all back together... If there is any grinding - what would be the cause? Is it possible to tighten the diff housing screws down to much?

DiZzYNaTiOn 03-15-2011 07:28 PM


Originally Posted by SDelaney (Post 8808453)
I haven't gotten it all back together yet, but I will do this tomorrow when I put it all back together... If there is any grinding - what would be the cause? Is it possible to tighten the diff housing screws down to much?

Possibly something fell in it while administering the diff oil, I had a peice of decal sticker in mine once years ago and the next time i took it apart the oil had turned yellow from the sticker and was really thick, some sort of reaction happend.

Possibly a peace of gasket broke off and fell in

But, like you said it might be fine, test it out and report back, its better safe the sorry.

bacchus 03-15-2011 08:32 PM

Its normal to feel alittle clicking when holding the diff in your hand and spinning the cups in opposite directions. If you feel a bind or grinding than something may be wrong. You can't over tighten the screws. They need to be tight but don't strip them.

Dave1GP 03-16-2011 12:09 AM

Always make sure the o-ring seal and paper gasket is intact. No way you can over tighten. There should be no grinding, if so you assmbled wrong or something has fallen in, like a piece of gasket. Re open, re asemble and see if still grinds.

SDelaney 03-16-2011 08:02 AM

The one thing I don't see in the exploded view is, there are the 4 flat metal pieces that sit at the end of the pins. These have a rounded side and a flat side. Does it matter which direction they go in? Right now I have it with the flat side at the top toward the ring gear.

When I get home from work I will tear it all apart again.

DiZzYNaTiOn 03-16-2011 09:30 AM


Originally Posted by SDelaney (Post 8810990)
The one thing I don't see in the exploded view is, there are the 4 flat metal pieces that sit at the end of the pins. These have a rounded side and a flat side. Does it matter which direction they go in? Right now I have it with the flat side at the top toward the ring gear.

When I get home from work I will tear it all apart again.

Also take some picks if your tearing down again, of inside of diff. and post them here

Stanton 03-16-2011 10:04 AM


Originally Posted by SDelaney (Post 8810990)
The one thing I don't see in the exploded view is, there are the 4 flat metal pieces that sit at the end of the pins. These have a rounded side and a flat side. Does it matter which direction they go in? Right now I have it with the flat side at the top toward the ring gear.

When I get home from work I will tear it all apart again.

Is this the type of diff you have? If so it's the heavy duty diff cup. The round ends of the metal inserts go down in the cup and the beveled sides go toward the cup. If you didn't put the beveled edges toward the cup, they will not seat correctly and will cause binding of the diff gears. Sounds like that could be the problem...
http://fastserve.horizonhobby.com/Pr...SB3528-100.jpg

token 03-16-2011 10:13 AM

if you have a standard diff cup, you need to make sure the gear are in correctly.

There are 2 different depth grooves in the cup.

Insert the the gears in the long slot first. The gears in the shorter slot will be on top.

If these are in wrong, the diff will lock up on you.

SDelaney 03-16-2011 11:16 AM


Originally Posted by Stanton (Post 8811593)
Is this the type of diff you have? If so it's the heavy duty diff cup. The round ends of the metal inserts go down in the cup and the beveled sides go toward the cup. If you didn't put the beveled edges toward the cup, they will not seat correctly and will cause binding of the diff gears. Sounds like that could be the problem...
http://fastserve.horizonhobby.com/Pr...SB3528-100.jpg

That is my DIFF and I didn't notice the beveled edge before, so this may be it. Man, guess I need to pay more attention to those little details.

I will report back tonight.


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