Big Rock Stock diff gasket

[SaltyLocal]

Good morning AF,

Is it possible to over tighten a BR stock diff case? So much so that the gasket starts to ease out? I didn’t think I was over tightening as I could’ve continued screwing it down. I changed diff fluid and noticed the gasket. I let it sit over night and this morning it was bone dry, so I don’t think it’s leaking. However, I can feel the gasket edges when running my finger over it, especially by each screw. Any tips? Here are a few pics. Do I need new gaskets?

 

[Hector_Fisher]

To answer the question: yes it's always possible to overtighten a fastener.

In the case of the plastic diff, whether the gasket would fail and squish out or whether the threads in the plastic would strip first is anyone's guess. I'd suspect the plastic would give way, IMO.

FWIW, my gaskets stick out a little too. Although, it almost looks like your gasket is splitting in multiple locations??? It's hard to tell from the pictures.

 

[SaltyLocal]

To answer the question: yes it's always possible to overtighten a fastener.

In the case of the plastic diff, whether the gasket would fail and squish out or whether the threads in the plastic would strip first is anyone's guess. I'd suspect the plastic would give way, IMO.

FWIW, my gaskets stick out a little too. Although, it almost looks like your gasket is splitting in multiple locations??? It's hard to tell from the pictures.

I’ll replace just to be safe. Thank you

 

[Velodromed]

I’ve done similar on an few occasions. Once when I over filled the diff (1/8th” from top is best) and it blew out much of the gasket. Another when I got a bit of oil in the screw holes and the hydraulic action of screwing in the screw blew parts of the gasket out and deformed the case at the top. Lastly I’ve gotten the gasket oil soaked before and it deformed out the sides in areas. So I’m careful when filling the diffs now and keep the gasket dry.

 

[SaltyLocal]

I’ve done similar on a few occasions. Once when I over filled the diff (1/8th” from top is best) and it blew out much of the gasket. Another when I got a bit of oil in the screw holes and the hydraulic action of screwing in the screw blew parts of the gasket out and deformed the case at the top. Lastly I’ve gotten the gasket oil soaked before and it deformed out the sides in areas. So I’m careful when filling the diffs now and keep the gasket dry.

Yes, I’m learning to be careful while messing with them. The plastic casing seem rather cheap. Wondering if there are metal/aluminum types that are compatible in the Big Rock. Any recommendations for both front and back?

 

[Velodromed]

Yes, I’m learning to be careful while messing with them. The plastic casing seem rather cheap. Wondering if there are metal/aluminum types that are compatible in the Big Rock. Any recommendations for both front and back?

Nope. The diff case is plastic on both the regular composite 3s diff and 4s diff that has a metal ring gear. It works fine, just have to take care. You don’t need to tighten the diff screws like crazy. Same goes with the rest of the plastic composite car. Except for the motor screws. I use cap heads, 243 loctite and crank them down.

 

[Grimbles]

First time I did it I overrightened so bad I split the top! I think you have overtightened but those gaskets also need replacing fairly regularly in my experience.

 

[SaltyLocal]

Nope. The diff case is plastic on both the regular composite 3s diff and 4s diff that has a metal ring gear. It works fine, just have to take care. You don’t need to tighten the diff screws like crazy. Same goes with the rest of the plastic composite car. Except for the motor screws. I use cap heads, 243 loctite and crank them down.

You use blue loctite on all four diff screws? I was hoping to find a set of aluminum diff casings for the BR.

 

[Velodromed]

You use blue loctite on all four diff screws? I was hoping to find a set of aluminum diff casings for the BR.

Nope, never use loctite on plastic. Only metal on metal. Metal diff cases are simply not needed with 3/4s Arrma cars. The plastic ones are fine. Even the composite gears are strong enough when set up right with good driving habits. Hell, 90% of the car is plastic composite which makes it light and durable. If you want metal get a 6s Arrma.

 

[Hector_Fisher]

Nope, never use loctite on plastic. Only metal on metal. Metal diff cases are simply not needed with 3/4s Arrma cars. The plastic ones are fine. Even the composite gears are strong enough when set up right with good driving habits. Hell, 90% of the car is plastic composite which makes it light and durable. If you want metal get a 6s Arrma.

Dang, beat me to it again!!!

 

[SrC]

You need a new gasket there. It was broken before or during assy.. The surfaces should be dry of any Oil before installing. Always have new spare gaskets. they are thin and fragile. Rarely can they be used again once taken apart.

Who was it that said to use Blue Threadlocker on plastic ????
Is not even part of the OP's issue.

 

[Velodromed]

You need a new gasket there. It was broken before or during assy.. The surfaces should be dry of any Oil before installing. Always have new spare gaskets. they are thin and fragile. Rarely can they be used again once taken apart.

Who was it that said to use Blue Threadlocker on plastic ????
Is not even part of the OP's issue.

I don’t think it was recommended, he asked. It’s a good question to ask when you’re starting out. I do reuse my 3s diff gaskets a couple times but I am extremely careful when opening the differential. If there’s any kind of noticeable wear or tear I replace it.

 

[SrC]

Need spare gaskets on hand before considering opening any diff. You might get lucky to re-use a gasket 3 times, or find that one tears when first removed. They get stuck.
They always tear at the screw holes. Then it is bricked. Will leak/pull out if you try to re-use it.
I use an exacto blade to carefully remove them, with luck in many cases. Sometimes not.