Another "Diff" Dumby needs help!

[*420+3RC*]

Ok so with a new complete diff and input gear I put it back in the yoke and make sure it's spinning freely and and snugged up. I paid it down onto the chassis double check to make sure everything is free spinning and it feels like it's catching and rubbing on the chassis but I cannot see any marks to show that. Any ideas? It's almost like when they yoke has any pressure on it like it's sitting down and its own grooves make it too tight on everything

 

[Velodromed]

Ok so with a new complete diff and input gear I put it back in the yoke and make sure it's spinning freely and and snugged up. I paid it down onto the chassis double check to make sure everything is free spinning and it feels like it's catching and rubbing on the chassis but I cannot see any marks to show that. Any ideas? It's almost like when they yoke has any pressure on it like it's sitting down and its own grooves make it too tight on everything

Hey buddy, are you sure it’s rubbing on the chassis or yoke and is not the gears itself catching? I spent near 2 hours this morning working on a new front differential and input gear that was catching on about a half inch of the ring gear. I was sure it wasn’t the yoke itself because I switched over to hot racing metal yokes (I love them!).

Very carefully I used a combination of fine grit double folded sandpaper (using the folded edge between the gear teeth to file down) and an X-Acto blade until I had everything working smooth all the way around. It seemed like the ring gear teeth were molded slightly high or ‘off’ in that one section. I took my time with it and was extremely cautious because I didn’t want to take too much material off at once.

 

[*420+3RC*]

Hey buddy, are you sure it’s rubbing on the chassis or yoke and is not the gears itself catching? I spent near 2 hours this morning working on a new front differential and input gear that was catching on about a half inch of the ring gear. I was sure it wasn’t the yoke itself because I switched over to hot racing metal yokes (I love them!).

Very carefully I used a combination of fine grit double folded sandpaper (using the folded edge between the gear teeth to file down) and an X-Acto blade until I had everything working smooth all the way around. It seemed like the ring gear teeth were molded slightly high or ‘off’ in that one section. I took my time with it and was extremely cautious because I didn’t want to take too much material off at once.

I have no idea what the heck is going on LOL. Per the usual. I'll check tonight when I get home

 

[GraniteFox]

The yoke has a notch in it for the side without the gear. Also no need to overtighten the yokes...especially when new. I tighten the two screws down snug and then back off each about 1.5 turns. Run it for about 10 packs and go back in and see if it needs any adjustment as the diff wears in.

 

[*420+3RC*]

The yoke has a notch in it for the side without the gear. Also no need to overtighten the yokes...especially when new. I tighten the two screws down snug and then back off each about 1.5 turns. Run it for about 10 packs and go back in and see if it needs any adjustment as the diff wears in.

Last time I didnt even have the screws in the yoke and still when laid into the chassis all goes to hell

 

[Velodromed]

Last time I didnt even have the screws in the yoke and still when laid into the chassis all goes to hell

Is the other diff working okay? Thinking you could try switching yokes and see if perhaps the yoke itself is warped. If that’s the case I could send you one of my old ones…

 

[*420+3RC*]

Is the other diff working okay? Thinking you could try switching yokes and see if perhaps the yoke itself is warped. If that’s the case I could send you one of my old ones…

Yes front is good. Its almost gonna have to come down to casing. Im not sure if diff cases or yokes.
Thats very cool of you to offer your yoke. I'm not off work till late tonight. But its first thing im picking up when I get home. The more ive been reading and alot of it ive done last couple weeks with being at a standstill. Is that aluminum yokes, possible drive shafts(not mine yet), shimming bell crank and possible aluminum there, pivot balls, are key in really nice firm handling.

You know it seems now that ive ran into more warped parts than anything. Im taking my truck in to someone to check it all out....idk.

 

[*420+3RC*]

Im gonna wait till tom night to take the front diff apart again. This is ridiculous. I went thru and sanded out all grooves to pretty close to same. But any pressure or sit the diff with yoke on (no screws in) in either side of housing and its so tight it won't move. So tight juat by testing it I see wear on the gears. I shouldnt having to be doing all this. Nothing near what most all folks here have run thru their rigs!! And all I do is fix crap. And at this point thats all this stuff is !! Over 600$ in a damn truck ive ran probably 20 whole batteries thru. Damn atleast drugs make me not care about the wasted money. I'm done

 

[Velodromed]

Im gonna wait till tom night to take the front diff apart again. This is ridiculous. I went thru and sanded out all grooves to pretty close to same. But any pressure or sit the diff with yoke on (no screws in) in either side of housing and its so tight it won't move. So tight juat by testing it I see wear on the gears. I shouldnt having to be doing all this. Nothing near what most all folks here have run thru their rigs!! And all I do is fix crap. And at this point thats all this stuff is !! Over 600$ in a damn truck ive ran probably 20 whole batteries thru. Damn atleast drugs make me not care about the wasted money. I'm done

Take a deep breath my friend, it’s OK. I get extremely frustrated with my cars at times. So I put them aside and mess with something else for awhile.

Good example is it the steering on my granite. Once I upgraded the servo and the Servo saver I could never get it to go straight. It’s driven me nuts for the last two months. So I decided to go back to all stock parts since they’re very cheap on Jenny’s.

A stock seering assembly (including servo saver) is less than two bucks so I got several. The typhon 6s, s652 servo is 18 kg, has 23t to match the stock servo saver and has more than enough power for a 3S car. So I got a couple of them. Only 16 bucks each. I went through and installed those yesterday, made sure all of my turnbuckles were adjusted correct and now my car steers like it’s new.

Sometimes upgraded parts provide the exact opposite of what I expected from an upgraded part. So far the only upgrades I really appreciate and have kept are the 6s shocks and the HR differential yokes.

It sounds like you need to work on the gears on your differential case more. What you’re describing is what I was dealing with on my new front differential. Once installed it was nearly locked. And like I said before, I spent a long time sanding down the ring/input gears and very carefully trimming them until I got perfectly smooth action. Ultimately I figured out that a section of the ring gear was simply higher then the rest of it. After sanding a 1/2” section of it down about a millimeter, it was much smoother. then I fine tuned it further by shaping the sanded down teeth a bit.

Take the screws out of the case, hold it finger tight and spin the ring/input gears. Feel for where they bind, note that area and start working on it. Take your time with it also.

Another experiment i did was to switch the shim from the ring side to the other side. If that helps loosen things up (it did with mine) then you know for sure it’s the ring/input gears binding, not the diff case. After you trim and fix the gears, switch the shim back.

Also make sure that you put it together right. Comparing it to your front differential is a good idea.

Sorry you’re having so much trouble buddy… but don’t give up. You got this! And the offer to send you a diff case stands. My stock ones were working fine, I just got these HR cases on a whim a couple months back so I want to try them. I have several extra stock diff cases so do not mind parting with one. Also let me know if you’re having any trouble with other certain parts. I may have extras you can try.

 

[*420+3RC*]

Take a deep breath my friend, it’s OK. I get extremely frustrated with my cars at times. So I put them aside and mess with something else for awhile.

Good example is it the steering on my granite. Once I upgraded the servo and the Servo saver I could never get it to go straight. It’s driven me nuts for the last two months. So I decided to go back to all stock parts since they’re very cheap on Jenny’s.

A stock seering assembly (including servo saver) is less than two bucks so I got several. The typhon 6s, s652 servo is 18 kg, has 23t to match the stock servo saver and has more than enough power for a 3S car. So I got a couple of them. Only 16 bucks each. I went through and installed those yesterday, made sure all of my turnbuckles were adjusted correct and now my car steers like it’s new.

Sometimes upgraded parts provide the exact opposite of what I expected from an upgraded part. So far the only upgrades I really appreciate and have kept are the 6s shocks and the HR differential yokes.

It sounds like you need to work on the gears on your differential case more. What you’re describing is what I was dealing with on my new front differential. Once installed it was nearly locked. And like I said before, I spent a long time sanding down the ring/input gears and very carefully trimming them until I got perfectly smooth action. Ultimately I figured out that a section of the ring gear was simply higher then the rest of it. After sanding a 1/2” section of it down about a millimeter, it was much smoother. then I fine tuned it further by shaping the sanded down teeth a bit.

Take the screws out of the case, hold it finger tight and spin the ring/input gears. Feel for where they bind, note that area and start working on it. Take your time with it also.

Another experiment i did was to switch the shim from the ring side to the other side. If that helps loosen things up (it did with mine) then you know for sure it’s the ring/input gears binding, not the diff case. After you trim and fix the gears, switch the shim back.

Also make sure that you put it together right. Comparing it to your front differential is a good idea.

Sorry you’re having so much trouble buddy… but don’t give up. You got this! And the offer to send you a diff case stands. My stock ones were working fine, I just got these HR cases on a whim a couple months back so I want to try them. I have several extra stock diff cases so do not mind parting with one. Also let me know if you’re having any trouble with other certain parts. I may have extras you can try.

Thx Velo. Im off a bit earlier tonight. A lot calmer today with it all. I'll switch shim and compare things tonight. New pics and all that. I really appreciate the time man.

 

[y noT]

Yes front is good. Its almost gonna have to come down to casing. Im not sure if diff cases or yokes.
Thats very cool of you to offer your yoke. I'm not off work till late tonight. But its first thing im picking up when I get home. The more ive been reading and alot of it ive done last couple weeks with being at a standstill. Is that aluminum yokes, possible drive shafts(not mine yet), shimming bell crank and possible aluminum there, pivot balls, are key in really nice firm handling.

You know it seems now that ive ran into more warped parts than anything. Im taking my truck in to someone to check it all out....idk.

My Kraton 6s came with the left front of the body tucked into the chassis that was warped out of the box, my wing is slightly lower on one side showing it was deformed slightly. The front bearing of the center diff was not set in the slot groove, but shoved between the tower and had melted the bearing holder and broke the center dogbone diff cup. QC is not the best on these things. The individual parts get better QC that a complete RTR vehicle. Things go out when new, then you warrany out the part and for some reason the individual part in a box works better.