• Welcome to RCTalk! 🚀

    Join the #1 RC community where hobbyists connect, share, and get expert advice on RC cars, trucks, boats, drones, and more!

    • ✓ Friendly & passionate RC enthusiasts
    • ✓ RC tips & troubleshooting
    • ✓ Buy, sell & trade RC gear
    • ✓ Share builds & upgrades

Torque on back wheels only...

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.
BOUTCH

BOUTCH

Hardcore RCTalk User
Messages
3,232
Reaction score
3
Points
0
Location
Canada, Québec
RC Driving Style
  1. Bashing
  2. Racing
:alarm: I just finished bashin and while i was playin...I stopped to check temp and i was holdin the rear bumper(in the gravel) and giving it some gas but its only the back wheels that was spinning and when i was holdin it in the air all wheels was turnin...but when i first got it all wheels was spinning on gravel...You guys think that there is something broken ? I checked and did not see anything...:horsecrap

howcome it made a double of the thread???
 
Last edited:
Check your front center cups and your wheel hex's. With the tires on the ground, hold the back of the truck off the ground and see if you can tell where things stop spinning when you give it gas.
 
olds97_lss said:
Check your front center cups and your wheel hex's. With the tires on the ground, hold the back of the truck off the ground and see if you can tell where things stop spinning when you give it gas.
Click to expand...

:confused: Is there a way to check that when the truck is'nt running?
 
try holding your back or front tires in the air and push the truck foward,to see which tires are turning freely,
 
it could be the front diffs are shot or something as simple as the grub screw on the drive cup came loose. lift the front wheel off the ground and spin 1 of the wheels. both should spin, but it opposit directs. ie...1 forward, 1 backward. if that happens the diffs are fine and i would look at the drive cups missing a grub screw.
 
:confused: (holdin the truck in the air)i turn the front left one and it does'nt turn the other wheel onthe other side...but i turn the front right one and it make the other wheel turn ????:ponder2: ...i guess my savage didn't like being treated like that...guess i should'nt tell I'm that will not be the last time...??? hehehe SUCKER

Instead of a 4x4...i got myself a 3x4, bet you dont have one of those...LOL

mmm...is it dangerous to drive it like that...you know, just to bash around ??:naughty:
And how much is a front diff. please??
 
Last edited:
I'm not sure its one of your diffs, it might be a drive shaft that lost her screw or something and isnt spinning at all. just a thought
 
Hold the front end up, both front wheels off the ground with both rear wheels on the ground. Spin one front wheel and the other front wheel should spin in the opposite direction.

Hold the rear end up, both rear wheels off the ground with both front wheels on the ground. Spin one rear wheel and the other rear wheel should spin in the opposite direction.

Hold the left side up, both left wheels off the ground with both right wheels on the ground. Spin the front left wheel and the rear left wheel should spin in the same direction.

Hold the right side up, both right wheels off the ground with both left wheels on the ground. Spin the front right wheel and the rear right wheel should spin in the same direction.
 
:marshall:OK!!!, is it dangerous for anything else to break if i wanna use it before i fix it ??? :thankyou:

rossb said:
Hold the front end up, both front wheels off the ground with both rear wheels on the ground. Spin one front wheel and the other front wheel should spin in the opposite direction.

Hold the rear end up, both rear wheels off the ground with both front wheels on the ground. Spin one rear wheel and the other rear wheel should spin in the opposite direction.

Hold the left side up, both left wheels off the ground with both right wheels on the ground. Spin the front left wheel and the rear left wheel should spin in the same direction.

Hold the right side up, both right wheels off the ground with both left wheels on the ground. Spin the front right wheel and the rear right wheel should spin in the same direction.
Click to expand...

:eek: My front left one turns freely without turnin the other wheels...CRAP!!!:depress:

Oza_X said:
good work lad! Keep up the professional bashing! :) :)
Click to expand...

thanks bud !!! And yes i will keep it up...OH YA !!!
 
HEY ! i just got an idea...call me crazy but would it damage anything if i tried my savage X........without front diff. ????:naughty:
 
no it wont be dangerous it will just be 2 wheel drive, try this. flip the savage over, hold both front wheels and manually turn the spur gar by hand and see is the center dogbone going up the the front end turns
 
BOUTCH said:
:eek: My front left one turns freely without turnin the other wheels...CRAP!!!:depress:
Click to expand...

You have to be more specific.

1) Are you saying the front-left will turn without spinning the front-right when both fronts are OFF the ground, and the rears are ON the ground?

2) Are you saying the front-left will turn without spinning the rear-left when both left side wheels are OFF the ground, and both right side wheels are ON the ground?

3) Are you saying both statements are true?

Statement 1 would mean either a damaged/missing front dog bone or front differential damage.

Statement 2 would mean either a damaged/missing front dog bone, front differential damage, damaged/missing center dog bone, or a missing drive cup pin.

Make sure you still have the allen-headed pins in the cups that go on the front and rear diff cases, and the center gear box (4 pins total). Those pins can fall out if they are not secured properly with loctite.

Check for Part 86095 in this pic (both diffs):
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P11.jpg

Also Part 86094 in this pic (both sides of the transmission):
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P21.jpg

I would not drive the truck in this condition. You will get very little traction and you will put a lot of stress on the parts that are still working. You may end up damaging something else.

This is an easy fix, just fix it.
 
rossb said:
You have to be more specific.

1) Are you saying the front-left will turn without spinning the front-right when both fronts are OFF the ground, and the rears are ON the ground?

2) Are you saying the front-left will turn without spinning the rear-left when both left side wheels are OFF the ground, and both right side wheels are ON the ground?

3) Are you saying both statements are true?

Statement 1 would mean either a damaged/missing front dog bone or front differential damage.

Statement 2 would mean either a damaged/missing front dog bone, front differential damage, damaged/missing center dog bone, or a missing drive cup pin.

Make sure you still have the allen-headed pins in the cups that go on the front and rear diff cases, and the center gear box (4 pins total). Those pins can fall out if they are not secured properly with loctite.

Check for Part 86095 in this pic (both diffs):
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P11.jpg

Also Part 86094 in this pic (both sides of the transmission):
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P21.jpg

I would not drive the truck in this condition. You will get very little traction and you will put a lot of stress on the parts that are still working. You may end up damaging something else.

This is an easy fix, just fix it.
Click to expand...

When the front-end is in the air, my front left wheel (when i turn it) does not make any other wheels turn at all...I took my front diff apart and it looks fine to me...:confused: Can not find what seems to be the prob. I dont know anymore...Gonna inpect it more later !!! So its not a good idea to run it without front diff. ??
 
eartaker 'S post from this thread

no it wont be dangerous it will just be 2 wheel drive, try this. flip the savage over, hold both front wheels and manually turn the spur gar by hand and see is the center dogbone going up the the front end turns
 
nicholas655 said:
eartaker 'S post from this thread

no it wont be dangerous it will just be 2 wheel drive, try this. flip the savage over, hold both front wheels and manually turn the spur gar by hand and see is the center dogbone going up the the front end turns
Click to expand...

I know!!! but I'm told 2 different thing by Rossb and eartaker about riding it without front diff...
 
I would not run it without a front diff. You will get no traction and you will put a lot of stress on your rear diff.

Did you check to make sure the allen-head pins are still in the diff's drive cups?

Did you check to make sure your front dog bones are still there, and not broken?

Did you check to make sure your center dog bones are still there, and not broken?


When you spin the front-left wheel do you see anything else moving around the front diff?

Did you make sure the bearing on the outsides of the diff are still ok? (part B032 in this pic, 2 on each diff).
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P11.jpg

Make sure you don't have a broken side pin inside the diff case (part Z260 in this pic, 2 in each diff). If you spin the front-left wheel and you see the front-left dog bone spinning, yet nothing happens to your other bones and wheels, then this pin is probably the culprit.
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P11.jpg

I'm betting you have a broken side pin inside the diff, Z260 as shown above.

Take the actual diff out of the truck, and out of its carrier. The round part in the center of this page:
http://www.hpiracing.com/graphics/instr/savage_ss/S25ss_P12.jpg
Spin one outdrive and the other outdrive must spin smoothly in the opposite direction. If that does not happen, or it feels really rough, your diff needs to come apart. Try holding one outdrive while you spin the other. You should not be able to stop the other outdrive from spinning without applying excessive force.
 
Last edited:
you might be worried for nothing also, i tried on mine.. if i hold the left or right tire and spin the other one it wont force the other to turn , i can turn one at a time if i keep holding the other one.
example, hold the left tire and turn the right one , it willl still turn .
 
Last edited:
nicholas655 said:
you might be worried for nothing also, i tried on mine.. if i hold the left or right tire and spin the other one it wont force the other to turn , i can turn one at a time if i keep holding the other one.
example, hold the left tire and turn the right one , it willl still turn .
Click to expand...

Umm, if you hold one tire and spin the other side the torque will go out the pinion to the other diff. It seems like you do not understand how an open diff works.
 
:surrender What kind of grease HPI uses in the diff...its a green grease ? The only grease i have is the ''castrol MP wheel bearings and chassis lubricant''...you think its ok?? And can i clean the Diff and the Diff case with brake cleaner and re-grease it after???:gulp:
 

RC Builds

Back
Top