Differential Bevel Gear - Shims.

[Man1c M0nk3y 564]

Hi all,

Would like to pick the hive mind again!

When I ‘upgraded’ the DT03’s diff gears to the DT02 splined set as used in the Desert Gator/Sand Viper (50602) I just installed them as per the manual without using the two shims that were in the packet. 

Sorting through some bits today and I can across the two shims roughly 0.5mm at a guess and got curious as to their use. Had a look in the online manual for the DT02 and they aren’t used, but surely they are there for a reason. 

So you clever lot, enlighten me!

Are they to take play out if it exists or and they to tighten the gears up and slow them down, or something else?

And if it’s to slow them down is this similar to using a thick/high cst oil?

I’ve currently avoided using the thick oil due to the gear casing not being sealed and not wanting the oil to eventually escape and coat the gear housing. Irrational maybe!

Anyway, these are the shims in question...

Should I ignore them or have they a useful purpose I can try?

[Juls1 1661]

In dt01,cc01,ta02/03 and TL01/M03/04 diffs these washers are normally used.  

Maybe the casing on the dt02 diff is slightly narrower? 

I recall thinking a similar thing when I built my dt02/03’s. But it was why isn’t this used in these diffs when it was in the old ones. 

[WillyChang 1814]

The spider gears bear a bit of force against the diff case sides... I'd have thought the washers prevent wear on the plastic casing.

Didn't know DT03 didn't use them!

[Man1c M0nk3y 564]

48 minutes ago, Juls1 said:

In dt01,cc01,ta02/03 and TL01/M03/04 diffs these washers are normally used.  

Maybe the casing on the dt02 diff is slightly narrower? 

I recall thinking a similar thing when I built my dt02/03’s. But it was why isn’t this used in these diffs when it was in the old ones. 

Possibly the diff size like you suggest. Just had a quick look online at a DT01 manual and the diff spur case is completely different to the DT02/03’s not looked at the other models you mention. 

29 minutes ago, WillyChang said:

The spider gears bear a bit of force against the diff case sides... I'd have thought the washers prevent wear on the plastic casing.

Didn't know DT03 didn't use them!

I wasn’t even aware of them until getting the splined gearset. The kit set in the DT03 didn’t have them hence me initially ignoring them. 

I can understand the idea of wear reduction. Likewise I’m wondering if they could be used to tighten and this slow down the gears similar to using heavy oil. A negative would be increased wear and maybe noise I guess. 

Just random pondering. It’s a wet and miserable day here and I’ve nothing better to do 😂 maybe they would actually serve absolutely no purpose on the DT02/03. 

[SurreyDad 124]

I had exactly the same thought when changing my DT-03 gears but I did notice that the diff case (BG3) and diff cover (BG2) both seemed to have a raised molded plastic shim in place which I assume negates the need for the extra shims. The shims were also used in the gf01 (which has splined gears), so I wonder if it was down to the molding in the diff cases?...anyway a good excuse to read through some manuals :-)

[WillyChang 1814]

9 hours ago, Man1c M0nk3y said:

 

I can understand the idea of wear reduction. Likewise I’m wondering if they could be used to tighten and this slow down the gears similar to using heavy oil. A negative would be increased wear and maybe noise I guess. 

 

Yeah crushing the gears pack to mash their gear mesh isn't what they're designed to hold up against. Heavy oil/grease creates drag and the energy is dissipated as heat without grinding down anything vital; badly meshed gears will just wear out quick.

There was another thread recently suggesting swapping washer for o-ring. I then suggested perhaps trying a "friction control pad" from a modern fancy sport yoyo  afaik they're a silicone of various rubberyness & sizewise they're about 19-22mm OD. 

[WillyChang 1814]

7 hours ago, SurreyDad said:

I had exactly the same thought when changing my DT-03 gears but I did notice that the diff case (BG3) and diff cover (BG2) both seemed to have a raised molded plastic shim in place which I assume negates the need for the extra shims. The shims were also used in the gf01 (which has splined gears), so I wonder if it was down to the molding in the diff cases?...anyway a good excuse to read through some manuals :-)

Ppl were complaining that DT03 diff are weaker than DT02?

 

[Man1c M0nk3y 564]

15 hours ago, SurreyDad said:

I had exactly the same thought when changing my DT-03 gears but I did notice that the diff case (BG3) and diff cover (BG2) both seemed to have a raised molded plastic shim in place which I assume negates the need for the extra shims. The shims were also used in the gf01 (which has splined gears), so I wonder if it was down to the molding in the diff cases?...anyway a good excuse to read through some manuals :-)

Seems a common wondering then!

First build for me so no experience of differences between generations/parts. 

7 hours ago, WillyChang said:

Yeah crushing the gears pack to mash their gear mesh isn't what they're designed to hold up against. Heavy oil/grease creates drag and the energy is dissipated as heat without grinding down anything vital; badly meshed gears will just wear out quick.

There was another thread recently suggesting swapping washer for o-ring. I then suggested perhaps trying a "friction control pad" from a modern fancy sport yoyo  afaik they're a silicone of various rubberyness & sizewise they're about 19-22mm OD. 

Yeah. I don’t think it would be worth the trade off tbh. I’ll still to heavy oils etc instead when I get to that stage of tuning. 

Loke I said. Curious to intended use and if it could still be utilised. I’m guessing not really. Not problem. Just a couple of extra spares that may one day get used for something. 

Thanks for the input all.