Kraton Spinning out instead of launching straight??

[DarkOwl]

On dirt, my kraton like to spin out instead of launching forward from a dig. My current differential oils are 50k(F)/1M(C)/30k(R). However I never had this issue before. It kind of just started happening and it's annoying.

My question is, is this a function of the center diff, or the rear diff? Also, is it caused by my oils being to thick, or too thin? Or something else?

Thanks everyone.

 

[Joeyskates]

Check your diffs first, if they are good I would say you have drag/binding somewhere. Mostly when you have differential action where you should not, you have a driveline issue. Binding on one tire will cause power to transfer to the opposite side. Check the driveline on the side it pulls towards

 

[StephenSchandelmayer]

Could be that a pin inside the diff is broken on one side, If you can put the truck in some dirt and try to watch all the tires you might be able to see one not spinning or not spinning quite as much as the others and then you would know where to inspect.

 

[Sandracer_NL]

What the guys aboved said, but also check your wheel bearings and diff bearings as they may need replacing. When doing this pop out an rear dogbone and spin your wheels on the free spinning wheel hex one by one, to see if one or more are wheels way out of balance.

 

[dure16]

If the other advice above doesn’t work, try a thinner center diff oil. That should keep the front tires on the ground and pulling the car in the direction they are pointed. The downside would be fewer wheelies and less air control.

For reference, 1/8 scale race truggies use ~10k in the center diff. I wouldn’t go that low for bashing but might try something like 200K or 300K.

 

[Hector_Fisher]

If the other advice above doesn’t work, try a thinner center diff oil. That should keep the front tires on the ground and pulling the car in the direction they are pointed. The downside would be fewer wheelies and less air control.

For reference, 1/8 scale race truggies use ~10k in the center diff. I wouldn’t go that low for bashing but might try something like 200K or 300K.

^ this

I've read in a few racing forums about when to go thicker/thinner center diff oil. Most people seemed to agree that "locking" the rear axles up more so to the front with thicker center oil is more likely to make the back step out in turns. Also, if when you're laying down power and the truck is lifting up the front, you're getting less traction on your front tires to steer.

Stock center diff oil is 100k or 200k i think.

 

[slick2500]

^ this

I've read in a few racing forums about when to go thicker/thinner center diff oil. Most people seemed to agree that "locking" the rear axles up more so to the front with thicker center oil is more likely to make the back step out in turns. Also, if when you're laying down power and the truck is lifting up the front, you're getting less traction on your front tires to steer.

Stock center diff oil is 100k or 200k i think.

100k is stock.

1m is rather thick for the center diff in the 6s line. I would drop it down to 500k and see if that helps.

 

[@9G]

I was having the same issue but on pavement and asphalt since I'm more of the parking lot basher/light drag race type. I run heavy oils all through (usually 500k to 1M rear...1M to 20M center...1M to 2.5M front). A LHS owner told me to check my shocks. He said use a caliper and measure to make sure the preload on both sides is equal. Do this with the batteries IN the car and do both front and rear. You'd be surprised how much a mm or two of difference and make a car spin out since when power hits you get more or less push on one side based on how even your shock preload is. I've seen a noticeable improvement since I've been doing it. I know my comment is off topic since you're talking diffs but it might help a little.

 

[DarkOwl]

S

Could be that a pin inside the diff is broken on one side, If you can put the truck in some dirt and try to watch all the tires you might be able to see one not spinning or not spinning quite as much as the others and then you would know where to inspect.

Sure enough, there is a broken internal pin on the right-side of the rear diff. Thanks for the help everyone.

^ this

I've read in a few racing forums about when to go thicker/thinner center diff oil. Most people seemed to agree that "locking" the rear axles up more so to the front with thicker center oil is more likely to make the back step out in turns. Also, if when you're laying down power and the truck is lifting up the front, you're getting less traction on your front tires to steer.

Stock center diff oil is 100k or 200k i think.

I really love riding my wheelie bar for 50 yards, and without my front tires ballooning. My driving style isn't race or track oriented. I'm not sure I want to sacrifice my 1m center lol. I might try 500k if I keep breaking diff pins.

 

[Adiabatic]

Hate when that happens. It usually locks the pin to the steel insert in the cup and I fail to catch it in time before it destroys the cup by spinning the insert free.