Savage X wheels binding

[Charbo]

I just bought a used savage 25 with a os30vg locally, and I already had a savage x with a seized engine. I swapped all the parts that I wanted over to the savage x chassis and now when I try to roll my truck even by hand, the wheels are binding up. It is about as if I was to hold the brakes about half way and try to push it, but both drive shafts turn when I roll it. I tred to run the truck for about 20 seconds and it would move but very slowly because of the binding. I have taken it back apart twice now to double check everything and I cannot find anything wrong with the drive train. Is there anything I can check? I have tried it with 2 different 3 speed transmissions and a 2 speed, adjusted the brake, and tried the complete front and rear bulk heads from both trucks. I am stumped and don't know what else to try, even the guy at the lhs said he couldn't find any reason for it.

 

[Jam Racing 1]

First off Welcome to the forum,

on to the trouble, is it possible the wheels are cranked down too tight? what hex drives are on the truck ? the stock cast ones or something upgrade wise ?? maybe a couple pictures of the rig in detail would be helpful also.....

 

[Charbo]

First off Welcome to the forum,

on to the trouble, is it possible the wheels are cranked down too tight? what hex drives are on the truck ? the stock cast ones or something upgrade wise ?? maybe a couple pictures of the rig in detail would be helpful also.....

I am using the stock hex drives. I just tried loosening the nuts and it made no difference.

 

[Charbo]

Is there anything specific I should get pics of?

 

[X]

If you remove both of the center dogbones does it get rid of the issue? This will help isolate where the problem is. When the dogbones are out try turning one wheel, does the opposite wheel turn backwards smoothly?

 

[Jr.]

Start eliminating things, as Jam and X have alluded too. I would pull the front and rear assemblies, and check them and the trans individually, then start reassembling and checking as you go until you can isolate it.

 

[Charbo]

If you remove both of the center dogbones does it get rid of the issue? This will help isolate where the problem is. When the dogbones are out try turning one wheel, does the opposite wheel turn backwards smoothly?

With both dog bones out, both ends and the transmission all turn smoothly and easily..I have no idea where the binding could be.

 

[X]

Any chance you have a warped dogbone? Maybe a drive cup has issues. Put one of the center dogbones back in and see if the problem returns.

 

[Charbo]

Any chance you have a warped dogbone? Maybe a drive cup has issues. Put one of the center dogbones back in and see if the problem returns.

If I try each end with the dogbone going to the transmission they work fine but as soon as I hook both up I get the binding.

 

[X]

Is this with the engine installed? If you turn the transmission with the spur gear it's fine (without the center dogbones in)?

 

[Jr.]

If I try each end with the dogbone going to the transmission they work fine but as soon as I hook both up I get the binding.

You've found your problem, either the diff ratios don't match, or one is flipped.

 

[Charbo]

Is this with the engine installed? If you turn the transmission with the spur gear it's fine (without the center dogbones in)?

Yes without the dogbones the engine and spur both turn freely and both cups on the transmission spin smoothly.

 

[Charbo]

You've found your problem, either the diff ratios don't match, or one is flipped.

I have not taken either diff out to be flipped, but I've tried it with the front and rear parts from both trucks with the same issue.

 

[X]

You've found your problem, either the diff ratios don't match, or one is flipped.

Very possible

 

[Jr.]

I have not taken either diff out to be flipped, but I've tried it with the front and rear parts from both trucks with the same issue.

Have you tried the front alone hooked to the trans, or the rear alone?

 

[X]

Have you tried the front alone hooked to the trans, or the rear alone?

If I try each end with the dogbone going to the transmission they work fine but as soon as I hook both up I get the binding.

 

[Charbo]

Have you tried the front alone hooked to the trans, or the rear alone?

Yes I have tried each end independently hooked to the trans and they are fine. I almost want to just run it in 2wd so at least I can drive it.

 

[X]

Yes I have tried each end independently hooked to the trans and they are fine. I almost want to just run it in 2wd so at least I can drive it.

It won't work well.......I've tried it. haha

 

[Charbo]

It won't work well.......I've tried it. haha

Ya I tried it before when I lost a drive cup set screw. Made it even worse cause it was fwd haha.

 

[X]

Ya I tried it before when I lost a drive cup set screw. Made it even worse cause it was fwd haha.

Haha yea, rwd is still "driveable" but fwd just spins the wheels.

 

[Charbo]

Haha yea, rwd is still "driveable" but fwd just spins the wheels.

Ya I would rather figure out the issue instead of avoid it. I guess I'll just have to drive the revo till I can get it fixed.

 

[Jr.]

Yes I have tried each end independently hooked to the trans and they are fine. I almost want to just run it in 2wd so at least I can drive it.

I know you said you've tried to mix and match, but this really points to ratios being different or diffs being flipped.

 

[Charbo]

I know you said you've tried to mix and match, but this really points to ratios being different or diffs being flipped.

I'm not sure how that could be when both trucks (the one I just bought and my old truck I'm using for parts) worked great. I am going to tear it all apart again today and see if I see something weird I didn't notice before..

 

[Jr.]

Well i learned the hard way HPI used two different rations over the years

 

[Charbo]

Well i learned the hard way HPI used two different rations over the years

I will check and make sure both diffs are from the same truck. If I ever need to take them out is there a way to tell which ones they are?

 

[Jr.]

There's a pretty drastic difference One is a 9 tooth pinion and the other is a 13? Not sure, I needed the newer 9 for mine

 

[Charbo]

Oh wow ok pretty obvious then haha.

 

[Jr.]

Yeah I figured out the issue pretty quickly lol. However, the guy before me didn't, because he had installed it that way.

 

[Charbo]

Well I pulled the entire truck apart today including the transmission and differentials. Everything seems fine but after I put it all back together I am still having the same issue. I am stumped, I have tried 2 matched sets of diffs that I know worked before, 3 transmissions, adjusted the brake and even tried it with the brake removed just to make sure that wasn't it..the guy at my lhs said that there is an employee there tomorrow that knows a lot about savages and he can take a look so hopefully I can get it fixed.

 

[Jam Racing 1]

So with the front and rear ends removed from the chassis wheels and tires attached they are working without any binding at all??? the tranny spins smoothly without any drive bones attached to them ??
But when all together you have the binding??
I would sure like to have that sitting on my bench so I could go thru it, because I am thinking something is bent causing this to happen.....one last question, have you had the tvp plates on a flat surface to check if anything is bent or twisted out of shape ??? sorry for all the questions, but ya got me stumped right now, and I have 30+ years playing with all kinda RC stuff and there just has got to be something you are overlooking......