The way I do it. I keep tightening the diff until the t bolts stops moving toward the center. That means the springs is fully compressed. I then loosen it 1/16 to 1/8 of a turn. I loosend 1/16th in the fronts and 1/8ths in the rear. Good luck.

I recently purchased a TC3 on eBay and it did not have a diff spring on either the front or the rear diffs. I bought some diff springs from Tower and I haven't been able to get them on. When you put the diff spring in, the diff bolt does not go through the spring so I can't start threading it through the t-bolt. Is there some special trick to getting it on? I'm gonna try again this weekend when the new carbide and diff balls come in. Some of them are quite worn... Thanks in advance for the help.

If the bolt won't go thru the spring, you either have the wrong spring or bolt.

When you say the bolt won't go through the spring, do you mean that the internal diameter of the spring is too small to allow the bolt to pass through? If so, then you definitely have the wrong bolt or the wrong spring. It should be quite an easy fit.

the sping # should ba asc 6582 and the bolt and t-nut should be a asc 6575.
hope that helps

The problem I have is that the diff bolt is way too short. It doesn't even look like it goes through the spring halfway. I'll try again this weekend. Thanks...

A couple of times I've found the AE diff thrust springs shipped in a very "uncompressed" state (I've re/built B4 and T4 diffs so many times:-) . Did you follow the step of pre-compressing the spring with a pair of pliers?

MIKE

Again assocoiated made 2 different diffs one that used a t-nut and one that used a locknut and are not compatable and they use diffrent outdrive hubs to.. and both are different in the way they are assembled.
the diff spring however is the same for both.

Yeah, I tried compressing the diff spring. It wasn't even close to coming through the spring and going into the t-nut. I'll try to rebuild it this weekend when the new carbide and diff balls come in.

I'm starting to get antsy. We had 70 degree weather here today and I wish my TC3 was ready to go... It'll have to wait... I don't want to rush this project and end up ruining the car...

This is getting freaky - I just compared a diff rebuild kit with the HD diff kit. The Rebuild kit is for the normal lightweight diff, it includes the captured nut and the plastic outdrives.

The thrust bolt was the same in both kits.
MIKE

I don't think you can ruin too much (touch wood:-) I imagine the most damaging thing you could do with the transmission is have it bind somewhere which would heat up the motor and ESC, which could lead to some electronics damage.

But if you can't get the thrust bolt to meet the retaining bolt, then I guess binding is the least of your worries :-(

Don't know how you are for hobby shops, but if I were you I would consider simply buying another HD diff kit. Compare the bolts and if your original bolt is not right, contact AE and get a freebie. I have done this with a T4 kit which included the wrong idler gear shaft, and my experience was that AE were super responsive and I had a gratis replacement part in no time flat.

If you have a helpful LHS, then take your bolt in there and compare it with a HD DIff Kit bolt ...

MIKE

i have both set ups and the diff screw looks to be the same in both.

input shafts
 

has anyone tried or are they running light weight input shafts and do you think they make a diff.

I stand corrected on the diff bolts they are the same only difference between the #6573 and 6575 diff bolt kits are one has a t-nut and the other has a lock nut. but the assembly of them is different. basicly the one with t-nut set up you place the diff spring in the long outdrive hub and put the t-nut in next.in the locknut type you putthe diff spring in the long outdrive hub then you put the diff screw with the thrust balls in next.

Just to expand,

There are plenty of other differences between the lightweight and HD diff kits of course. The lightweight has the captured thrust nut (as you say) versus the T bolt. But also, the lightweight has plastic as opposed to metal outdrives, and also the lightweight diff rings are the "D" rings whereas the HD kit is just a plain round diff ring.

Why they didn't just make a single diff which works and supply various levels of outdrives I don't know.

MIKE