Should I shim?

[kratonwatch]

I have slight and I mean SLIGHT play in my center drive shafts fore and aft. Should I shim these with these or leave them alone? I never ran into any trouble with this little bit of play, but now I’m wondering if I should for the health of the gears.

Running HW max 5 800kv.

https://www.horizonhobby.com/produc...OtHcY-KAafk7gos9zgeWs_zCybsZ8PfRoC77cQAvD_BwE

 

[Jluther@becoinc]

I have slight and I mean SLIGHT play in my center drive shafts fore and aft. Should I shim these with these or leave them alone? I never ran into any trouble with this little bit of play, but now I’m wondering if I should for the health of the gears.

Running HW max 5 800kv.

https://www.horizonhobby.com/produc...OtHcY-KAafk7gos9zgeWs_zCybsZ8PfRoC77cQAvD_BwE

I’m not sure I understand what you mean. Are you talking about play at each diff or the dog bones rocking back and forth? If you have room for shims then you definitely need them. The diff should be pushed as tight as possible towards the input gear. Only shim on the ring gear side.

 

[Hector_Fisher]

If you're referring to the centre dogbone driveshafts and how there is play in how they can move fore and after, then it's good to leave it that way. You'll need some give/clearance for when the chassis flexes when landing a jump. Take out all that slack and now your center driveshafts will act like chassis braces and the diffs and bulkhead will feel that pain too.

 

[kratonwatch]

I’m not sure I understand what you mean. Are you talking about play at each diff or the dog bones rocking back and forth? If you have room for shims then you definitely need them. The diff should be pushed as tight as possible towards the input gear. Only shim on the ring gear side.

I’m talking play at each diff (front and rear) where the center drive shaft goes into the ring gear. I can move it fore and aft not even a millimeter

So to shim this I would remove the ring gear and shim behind it, not on the bearing side?

Pic for reference: shim would go behind this ring gear, yes?

 

[parcou]

I’m talking play at each diff (front and rear) where the center drive shaft goes into the ring gear. I can move it fore and aft not even a millimeter

So to shim this I would remove the ring gear and shim behind it, not on the bearing side?

Pic for reference: shim would go behind this ring gear, yes?

View attachment 349447

Yes....shim would go behind the input gear pictured.

Honestly, for me....I like to have that assembly removed and in my hand, with the diff back in and the diff cover secured down, and turn the input gear to hear and see how well they mess. Some rigs I do not need, but after some runs later, it is needed.

 

[Diem Turner]

Yes....shim would go behind the input gear pictured.

Honestly, for me....I like to have that assembly removed and in my hand, with the diff back in and the diff cover secured down, and turn the input gear to hear and see how well they mess. Some rigs I do not need, but after some runs later, it is needed.

I've had better results putting the ship behind the large bearing the input pinion sits in. I've found that the back side of the pinion can dig into the shim if placed directly behind it which led to binding in my diff assembly. It's possible that this isn't the case for everyone but I do remember seeing or hearing others complain about this same issue.

I thought it might be worth mentioning in case the OP runs into any such similar problems.

 

[kratonwatch]

I've had better results putting the ship behind the large bearing the input pinion sits in. I've found that the back side of the pinion can dig into the shim if placed directly behind it which led to binding in my diff assembly. It's possible that this isn't the case for everyone but I do remember seeing or hearing others complain about this same issue.

I thought it might be worth mentioning in case the OP runs into any such similar problems.

I saw a YouTube video of this and thought this might be the way to go. Since I’m redoing the diffs with vitavon housing and diffs I thought it was a good time to shim as well. I ordered the linked shims and will get to work when all parts arrive.

Thanks everyone for their input. Pun intended

 

[parcou]

I've had better results putting the ship behind the large bearing the input pinion sits in. I've found that the back side of the pinion can dig into the shim if placed directly behind it which led to binding in my diff assembly. It's possible that this isn't the case for everyone but I do remember seeing or hearing others complain about this same issue.

I thought it might be worth mentioning in case the OP runs into any such similar problems.

You are very correct....when I do it or service the diff input, I go back with a new flat shim... I did not have shims as big as the bearing. I do now so I might give that a try I have heard the same

 

[kratonwatch]

You are very correct....when I do it or service the diff input, I go back with a new flat shim... I did not have shims as big as the bearing. I do now so I might give that a try I have heard the same

From a guy who has not done it yet, This seems like the most practical approach since it moves the mesh into each other instead of sliding left to right.

From a guy who has not done it yet, This seems like the most practical approach since it moves the mesh into each other instead of sliding left to right.

The shims I have coming might be a bit smaller than the bearing. Hoping this isn’t a problem