Big Rock BIG ROCK DIFF UPGRADE PROBLEM

[arrma 43]

I have the arrma big rock. I recently upgraded the rear diff gears to metal but when I reassemble, the gears mesh is to tight when tightening yoke diff case , why is this?? Never had this problem with the composite gears in there? Same with internal sun gears housing, to tight?? i BOUGHT THE METTAL CORWN, AND IMPUT GEAR IF NEW CASE, EVEN THE INTERNAL GEARS WONT MOVE WHEN TIGHENING CASE? CANT USE MY TRUCK NOW,

 

[dure16]

Did your shift button get stuck?

You may have to shim.

 

[Kla912000]

Seems like you didn't assemble it correctly.

 

[arrma 43]

I put everything back the same way will all the shims. would using hot racing metal cases fix this?
can some post a vid on this?

Did your shift button get stuck?

You may have to shim.

whats a shift button?

 

[morrjr71]

Does the diff turn freely before you hook up the driveshaft? If so, you may have the input shaft gear issue. From what I've read here on the forum, if you have the newer version that has the black plastic hut inside the slipper shaft it could be your new input gear causing problem. The Hot Racing input gear was designed for the older slipper tightening system without the plastic nut, and it's too long to run with the plastic nut installed. You can shorten the shaft on the new input gear, or you can remove the plastic nut and use Loctite on the the slipper screw. Do a search here for more info on that issue.

If the issue is with the diff yoke being too tight, that is a known issue with the stock plastic yokes, even on the stock diff. To correct it you may have to loosen the case screws just a bit, or purchase the Hot Racing aluminum yokes. Since you already upgraded the diffs, I suggest you buy the new yokes.

 

[arrma 43]

Does the diff turn freely before you hook up the driveshaft? If so, you may have the input shaft gear issue. From what I've read here on the forum, if you have the newer version that has the black plastic hut inside the slipper shaft it could be your new input gear causing problem. The Hot Racing input gear was designed for the older slipper tightening system without the plastic nut, and it's too long to run with the plastic nut installed. You can shorten the shaft on the new input gear, or you can remove the plastic nut and use Loctite on the the slipper screw. Do a search here for more info on that issue.

If the issue is with the diff yoke being too tight, that is a known issue with the stock plastic yokes, even on the stock diff. To correct it you may have to loosen the case screws just a bit, or purchase the Hot Racing aluminum yokes. Since you already upgraded the diffs, I suggest you buy the new yokes.

hi! with the new crown metal gear and imput metal gear installed, plus the new diff case they recommended, after tighening it all up, cant move the diff from either side at all? seems this new case meshes the internal planet gears to much??

hi! with the new crown metal gear and imput metal gear installed, plus the new diff case they recommended, after tighening it all up, cant move the diff from either side at all? seems this new case meshes the internal planet gears to much??

I bought what they said and it does not work, put it all back from diagram. might have to take stalk one out from front of truck to see how it works?

hi! with the new crown metal gear and imput metal gear installed, plus the new diff case they recommended, after tighening it all up, cant move the diff from either side at all? seems this new case meshes the internal planet gears to much??

I bought what they said and it does not work, put it all back from diagram. might have to take stalk one out from front of truck to see how it works?

without have the yoke case on it moves loose and the way it should, tighen it up and terrible. binds like hell.

 

[Kla912000]

You keep saying "got what they told me to get." Who is "they", who told you what to get?

Any way you can post a video of what's going on? That would help us help you.

 

[arrma 43]

You keep saying "got what they told me to get." Who is "they", who told you what to get?

Any way you can post a video of what's going on? That would help us help you.

yes I bought the arrma upgrades to make this work and its does not, it makes the gears bind!

 

[arrma 43]

hi! with the new crown metal gear and imput metal gear installed, plus the new diff case they recommended, after tighening it all up, cant move the diff from either side at all? seems this new case meshes the internal planet gears to much??

I bought what they said and it does not work, put it all back from diagram. might have to take stalk one out from front of truck to see how it works?

without have the yoke case on it moves loose and the way it should, tighen it up and terrible. binds like hell.

will the hot racing item s fix this??? the metal diff case and metal yokes?

 

[dure16]

tighen it up and terrible. binds like hell

Have you tried not tightening it all the way?

 

[arrma 43]

I have to not tighten it all for the gears to run smooth. the plastic yokes for metal gears will not fit at all.

 

[Kla912000]

I have to not tighten it all for the gears to run smooth. the plastic yokes for metal gears will not fit at all.

Are you sure you have the yokes on correctly? Each side is different and they go a certain way.

 

[arrma 43]

how do you post video on here?

 

[slick2500]

how do you post video on here?

Upload it to Youtube then post a link.

So the diff itself is binding like it won't turn once you put the crown gear on the cup? Or the entire assembly inside the yolk won't turn?

yes I bought the arrma upgrades to make this work and its does not, it makes the gears bind!

Way to not even come close to answering his question.

What specific parts did you buy? Give us a link a picture something.

 

[arrma 43]

yes when I screw the 4 screws to tighten case to crown, cant move the internal gears, seems the optional case and stalk yoke gears bind the heck out of things.

 

[Kla912000]

Upload it to Youtube then post a link.

So the diff itself is binding like it won't turn once you put the crown gear on the cup? Or the entire assembly inside the yolk won't turn?

Way to not even come close to answering his question.

What specific parts did you buy? Give us a link a picture something.

Hey @slick2500, that's what I was trying to find out. Who told him to buy what parts? Wondered why he didn't just ask here?

 

[slick2500]

Try removing one or both of the shims inside the diff, assemble it dry first so you aren't wasting diff fluid, then see what happens. Also if you have too remove the external shim as well.

 

[arrma 43]

Hey @slick2500, that's what I was trying to find out. Who told him to buy what parts? Wondered why he didn't just ask here?

arrma part number ar310722

tried tonight, this case wont take on the metal internal gears, tried turning it once put together, will bind and surely wreck my truck!

 

[GRC]

yes when I screw the 4 screws to tighten case to crown, cant move the internal gears, seems the optional case and stalk yoke gears bind the heck out of things.

You are talking about 2 different things here. 1) the 4 differential screws, 2) the yoke

Does the differential spin smoothly after you tighten down the 4 screws? If not, there can be a few different reasons.
- Your internal gears are chipped/damaged. Check them closely. Do they spin smoothly before you tighten down the crown?
- The pins are not fully seated. I had a problem where differential oil got into the holes that the pins sit in and prevented the pins from going all the way in. When I tried to close the diff, it bound up. Make sure the pins are pushed all the way in. You may have to empty the differential oil and clean out the holes. Put the pins all the way in first, then add the differential oil. Don't get any diff oil on top of the pins. Wipe them off if you do, or they may have trouble going into the top holes.
- I'm not sure about the metal diffs, but overtightening the 4 screws on the stock differentials can cause them to bind.

After you fix the issue with closing the diff. There are a few reasons the diff can bind when tightening the yoke
- the differential bearings are seized
- the two sides of the yoke are not identical. One side has a little tab on the inside. That tab goes on the side opposite from the ring gear. If you put it on the ring gear side, it will rub the back of the ring gear and bind the differential.
- make sure the differential bearings are fully seated. Again, I'm not sure about the metal diffs, but on the stock diffs, the bearings on either side of the differential can be difficult to push all the way on. If they're not fully seated, the yoke won't fit properly.
- Dirt on the differential or input gears can make them bind. I've even had excessive grease on the gears cause them to bind. Make sure all the gears are clean and the grease is applied evenly.
- the external shim is usually on the ring gear side. After checking all the things above, if the mesh with the input gear is still too tight, you can switch the shim to the opposite side to loosen up the mesh

 

[Kla912000]

You are talking about 2 different things here. 1) the 4 differential screws, 2) the yoke

Does the differential spin smoothly after you tighten down the 4 screws? If not, there can be a few different reasons.
- Your internal gears are chipped/damaged. Check them closely. Do they spin smoothly before you tighten down the crown?
- The pins are not fully seated. I had a problem where differential oil got into the holes that the pins sit in and prevented the pins from going all the way in. When I tried to close the diff, it bound up. Make sure the pins are pushed all the way in. You may have to empty the differential oil and clean out the holes. Put the pins all the way in first, then add the differential oil. Don't get any diff oil on top of the pins. Wipe them off if you do, or they may have trouble going into the top holes.
- I'm not sure about the metal diffs, but overtightening the 4 screws on the stock differentials can cause them to bind.

After you fix the issue with closing the diff. There are a few reasons the diff can bind when tightening the yoke
- the differential bearings are seized
- the two sides of the yoke are not identical. One side has a little tab on the inside. That tab goes on the side opposite from the ring gear. If you put it on the ring gear side, it will rub the back of the ring gear and bind the differential.
- make sure the differential bearings are fully seated. Again, I'm not sure about the metal diffs, but on the stock diffs, the bearings on either side of the differential can be difficult to push all the way on. If they're not fully seated, the yoke won't fit properly.
- Dirt on the differential or input gears can make them bind. I've even had excessive grease on the gears cause them to bind. Make sure all the gears are clean and the grease is applied evenly.
- the external shim is usually on the ring gear side. After checking all the things above, if the mesh with the input gear is still too tight, you can switch the shim to the opposite side to loosen up the mesh

Very excellent and informative post.