Results 1 to 40 of 40
  1. #1
    RC Qualifier
    Join Date
    May 2011
    Posts
    374

    Flm hybrid bulks

    Hey everybody so I just got my hybrid bulks in the mail and I'm trying to assemble them, I got a bunch of screws some pins, gears and a few other things but I don't really know exactly how it all goes together could someone please post everything I would need to know about assembling these?
    The smartest person, asks the most questions...

  2. #2
    RC Enthusiast
    Join Date
    Aug 2013
    Posts
    29
    Just like a regular diff. Trial and error my friend.


    Sent from my iPad using Tapatalk HD

  3. #3
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    I'm mostly unsure about shimming and how to mount the cup onto the pinion gear shaft as there is no hole, I guess I just use a set screw? Also there is no grease inside the diff, but guessing it should probably have some?
    The smartest person, asks the most questions...

  4. #4
    RC Enthusiast
    Join Date
    Aug 2013
    Posts
    29
    Did u get them used?


    Sent from my iPad using Tapatalk HD

  5. #5
    RC Turnbuckle Jr. Wildman4910's Avatar
    Join Date
    Jun 2009
    Location
    Cocoa Florida
    Posts
    3,964
    Silicone diff fluid goes in the diff cup.
    Grease goes onto the ring & pinion.
    You local auto parts store will have a tub of Mobil 1 synthetic grease for about $8, it will last you many years compaired to the small tube that most LHS carry for the same $5.
    http://www.autozone.com/autozone/acc...er=934751_0_0_

    A diff is a diff, they go together the same way.
    Here's an older thread on it but the info's still good.
    http://traxxas.com/forums/showthread...-Diff-Shim-Mod

    Toss up a pic of the pinion, if it has no hole in it like the Traxxas pinions do, your gonna need a UE or RC Monster style dr cup for it.
    http://www.rc-monster.com/proddetail...Hardened+steel

    Look out for the tree/crunch!

    LiPo? Naw NITRO!!

  6. #6
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    I will post pictures of everything I got soon I bought it brand-new...for the meantime what weight should I use in the front and rear diffs for oil
    The smartest person, asks the most questions...

  7. #7
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    I'll post some info when I get home later today. I just got mine installed recently, and learned a few lessons. Are you using the steel CVDs?

  8. #8
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Yes, I have traxxas steel drive shafts
    The smartest person, asks the most questions...

  9. #9
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    Sounds like your setup is the same as mine. I'm frustrated because there was a really good post on shimming the hybrid bulks with pictures, and now I can't find it. But EMAXXBRUSHLESS explains it in this thread. You'll need 8x10mm and 13x16mm shims. I used these: 8x10mm and 13x16mm.

    The pinion gears have 5mm shafts while the Traxxas steel CVDs are 6mm. You can try using the little aluminum sleeves that shipped with the bulks to enlarge the 5mm shafts to 6mm, but I discovered yesterday that the aluminum just doesn't hold up well. You're better off using the included 5mm drive cups. You can simply pop one cup off of each CVD, and use the FLM ones instead. The only thing I don't like about this is that the Traxxas CVD boots won't mount properly on the FLM cups because there are no holes for the little rubber "pegs" inside the boots. I haven't figured out a good solution for that yet. As you discovered, the pinions don't have holes, so you have to use the included set screws to hold everything together. Of course, you'll want to screw the set screws onto the flat part of the pinion gear shafts. I don't know if I'm willing to attempt drilling holes through those pinion gears.

    The problem I had is that one of my bulks was missing the drive cup, and I'm still waiting for FLM to ship a replacement. In the meantime, I think I'll just order the UE 5mm drive cups to use long-term since everyone says they're some of the strongest available.

    As a side note, I had to make two modifications to get everything to fit together properly. 1) I had grind out about 1mm of aluminum from the area where the chassis meets the read hybrid bulk because they didn't want to fit together properly. I decided that it was safer to grind down the bulk rather than the chassis since the bulk is the stronger part. 2) I had to grind out my UE KnuckleHeads a bit to fit on the hybrid bulks because the screw on the top of the bulk was too tall. Of course, this shouldn't be an issue if you're using the FLM shock towers. I will say that the 7075 aluminum that UE uses is superior to the 6061 aluminum that FLM uses. It was a lot more difficult to grind down the UE KnuckleHeads than the FLM bulks.

  10. #10
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    I can probably post some pictures if you need them. I can't get any of the diffs since they're already installed, but I can get some of the area that I had to grind for the chassis to fit properly and of the drive cups. Let me know if that would be helpful.

  11. #11
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    pictures would help.............okay so here are some pics of everything i got

    here is the pinion, i guess i just use a set screw to hold down the cup onto it. which drive cup will fit this pinion?

    now this sleeve that came with the bulks fits onto the pinion but i dont know what its for or if i even use it

    also this ring came with everything it fits perfectly into the gear box, does it go there? or again do i not use this part


    also am i putting the shims on the outside of the diff in the gear box? and could someone post pictures of where to put the shims?
    Last edited by Dann117elite; 09-29-2013 at 12:46 PM.
    The smartest person, asks the most questions...

  12. #12
    RC Champion
    Join Date
    Feb 2012
    Location
    Brookline, NH
    Posts
    1,199
    The little sleeve goes on the pinion to allow you to use a 6mm drive cup. The 13x16mm shim goes in the gear box on the outside of the diff just like you show in your pic. (you will need more 13x16mm shims than the one they give you to shim it) Get some 13x16x.02mm and some 13x16x.03mm
    As for the trx rubber boots, just take some wire cutters and cut the pegs off the inside of them.
    Heres some good info to read through on diff shimming.
    http://www.rc-monster.com/forum/showthread.php?t=28453
    Search around theres more info about shimming your diffs.
    Last edited by EMAXXBRUSHLESS; 09-29-2013 at 02:17 PM.

  13. #13
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    Sorry about the delay. I ended up rebuilding a friend's E-Maxx today, so I didn't get a chance to take any pictures of my FLM set up. But you're on the right track. I found those instructions I was looking for before for shimming. You can find them here. The key with shimming to to take any "play" out of the diff so that it doesn't have any room to "slip" and destroy itself. After putting everything together, if you can move the diff side-to-side in the bulk or you can move the pinion gear in and out, then something's loose. At the same time, you don't want everything to be so tight that it binds. You really just have to play with it for a while until everything just feels smooth and solid.

    Also, I'm assuming that you opened up the diffs, replaced the cups with the included shafts, and filled them up with diff oil. I'm currently using 120K in the rear and 70K in the front.

    As I mentioned in a previous post, I didn't have much luck using the little aluminum sleeve to enlarge the 5mm pinion to 6mm for my CVDs. It just ended up chewing up the sleeve. You're better off using the included 5mm cups instead.

    Hope that helps.

  14. #14
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Okay thanks guys I will post pics of each step along the way to ensure I'm doing this correctly... Why do you say to remove the cups and use the shafts instead? And that weight of diff oil, would that be good for all terrain and various speeds? How do you really judge that
    The smartest person, asks the most questions...

  15. #15
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    One more thing, I'm noticing I'm gonna have to put quite a few shims on the ring gear side, but just to clarify, adding shims to the ring gear side is to properly rais the diff so that the gears mess together right? And adding shims to the other side is to ensure the gear is sitting straight and not at an angle while messing with the pinion gear?
    The smartest person, asks the most questions...

  16. #16
    RC Champion
    Join Date
    Feb 2012
    Location
    Brookline, NH
    Posts
    1,199
    The shims on the ring gear side do the same thing as the shims on the other side. They keep the diff from moving from side to side inside the diff case, and hold it there so the gears mesh correctly. Shim the diff in the case with out the pinion installed first.
    This will tell you how many shims total you need for both sides. Then shim the pinion gear so it just clears the diff cup and makes good teeth contact with the ring gear. Install the pinion gear with the drive cup on to hold it from moving in and out. (Then move shims from one side to the other until the gears mesh together. Keep moving the diff over by moving the shims from one side to the other until the gears start to bind up and feel notchy. Then move one back. It should feel nice and smooth when turning the pinion shaft when done. If there is one small spot that feels a tiny bit notchy that's ok. It will wear in.
    Remember you need to turn the pinion about three revolutions to go all the way around the ring gear once for checking and you also want to tighten the screws holding the diff case together a little each time to get a propper feel for the gear mesh.
    There should be just a tiny tiny little bit of play in the diff side to side when its done. You don't want to get it to tight and preload the bearings. Once you get it shimmed then put a bead of grease on the ring gear and put it together.
    You will probably have to assembly and disassemble it several times to get it shimmed right.
    For all around use try running 5k rear 7k front or 7k rear 10k front. Generally people run heavier oil in the front. The heavier the diff oil the more posi effect it will have. I put 5k rear 7k front in my latest project with 1/8th scale diffs.
    Hope this helps you out mate.

  17. #17
    RC Qualifier
    Join Date
    Aug 2012
    Location
    Albany, New York
    Posts
    463

  18. #18
    RC Qualifier
    Join Date
    Aug 2012
    Location
    Albany, New York
    Posts
    463
    That video really helped me....check it out when putting the FLM Hybrid Bulks together!
    I later also found this video but never fully watched it :
    http://www.youtube.com/watch?v=OBQqE7PlHHY

  19. #19
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    Usman, good job on the links! I wish I had those handy when I was putting together my bulks.

    Dann117elite, the first video does a great job of explaining the shimming process, and it lines up pretty well with EMAXXBRUSHLESS's instructions. In that video, you can see that he has the "short shafts" installed. Those are necessary to use the steel CVDs (axles) as well as the stock axles. He also installs the included 5mm drive cup on the pinion gear (which is what I recommend as well).

    For comparison, the second video shows the diff with the drive cups installed rather than the "short shafts". You have to take the diffs apart to swap out the drive cups for the "short shafts". If my truck wasn't already mostly assembled, I'd take some pictures for you. I looked at it tonight, and I just can't get any good shots without breaking it down.

    As a side note, that aluminum sleeve got stuck in the drive cup from my front CVD, and I can't get it out. Yet another reason to skip the aluminum sleeve, and just use the included 5mm drive cup.
    Last edited by dildano; 09-30-2013 at 08:38 PM.

  20. #20
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Okay thanks guys for all the help, this is my first diff shimming so I just wanna do it right, in the video he puts the shims on the outside of the bearing in the gear box, but on the other link to the flm forum page the pic shows putting the shims behind the bearing, so where do I really place the shims?
    The smartest person, asks the most questions...

  21. #21
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    The shims for the sides (axles) go between the bearing and the gear box. At least, that's the way I did mine. I'm not sure that it makes much difference in the end since it has the same effect either way.

  22. #22
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Alright thanks for all the help guys I'll be sure to post pictures of the diffs along the way
    The smartest person, asks the most questions...

  23. #23
    RC Qualifier
    Join Date
    Feb 2012
    Posts
    590
    Where did you get that stuff, and if you would...what are all the part numbers for a complete diff build set-up?

  24. #24
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    It's all one kit just go to flm website and you can find them under emaxx parts .... How much fluid should I put in the diff?
    The smartest person, asks the most questions...

  25. #25
    RC Qualifier
    Join Date
    Feb 2012
    Posts
    590
    Okay cool, but what does FLM stand for? Oh yes, before I forget, does the diff kit come with the shims you need? If not, where do you get them.

  26. #26
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Flm is the company name, it stands for Fast Lane Machine, no the shims don't come with it, if you look up above at the other posts you'll see a link where you can get the shims
    The smartest person, asks the most questions...

  27. #27
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    How do I know if I shim the Pinion or not? I followed the video and it goes together smoothly with the pinion gear without any shims, I added one shim to see if it needed and it became slightly notchy and hard to turn by the diff shafts. does this mean I should remove that shim because it was fine without it?
    The smartest person, asks the most questions...

  28. #28
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    Yeah, I don't think I had to shim my pinion either. You definitely don't want it to be notchy. Also, fill the diff all the way up. Let it leak out as you screw the ring gear on to make sure it's full, and just wipe off the excess.

  29. #29
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Okay thanks, cause what I did was i shimmed it so that it felt nice and smooth, then I added one more shim and it got tight so I removed that one shim so that it was good and smooth again and I moved the pinion very very slightly and I noticed the diff shafts moving just like in the video so I'm pretty sure my pinion is good just the way it is
    The smartest person, asks the most questions...

  30. #30
    RC Champion
    Join Date
    Feb 2012
    Location
    Brookline, NH
    Posts
    1,199
    I shim the pinion first to get all the gear teeth contact you can get with out the pinion hitting the diff cup. Then shim the diff side to side to get the gear mesh. The ring and pinion that comes with the flm uhb has wider teeth than some of the others so you probably be ok. But its still a good idea to shim the pinion first. More teeth contact = more strength and longer life.

  31. #31
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Okay so how do I know how many shims to put on the pinion? Do I add them till the pinion hits the diff cup then take one out, and it should be good?
    The smartest person, asks the most questions...

  32. #32
    RC Champion
    Join Date
    Feb 2012
    Location
    Brookline, NH
    Posts
    1,199
    [QUOTE=Dann117elite;5585545]Okay so how do I know how many shims to put on the pinion? Do I add them till the pinion hits the diff cup then take one out, and it should be good?[/QUOTE

    Yes, shim the pinion so that there is just a tiny bit of room between the end of the pinion and the diff cup. Make shore it goes all the way around with out rubbing on the cup.

  33. #33
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    Okay and if it touches simply remove one shim?
    The smartest person, asks the most questions...

  34. #34
    RC Champion
    Join Date
    Feb 2012
    Location
    Brookline, NH
    Posts
    1,199
    Yep, one or two depending on how thick the shims are. You don't want it so close that it starts rubbing after everything wears in good. I shim mine so it has approx. 015 clearance.

  35. #35
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    So it turns out that adding one shim to the pinion is one shim too many, it started to touch the diff cup, once I give it a couple runs and take it all apart again to check for any existing play ill see if it needs a shim but for now it appears to be good. Thanks for all the help guys ill post pics soon of everything I did to shim theses diff, any comments or reconditions would be appreciated
    The smartest person, asks the most questions...

  36. #36
    RC Qualifier
    Join Date
    May 2011
    Posts
    374
    sorry for the late respond... okay so here is how i assembled my flm bulks

    obviously the little pin sits in the bulk and helps hold it together

    then i took the supplied shim and put it on the side where the ring gear will sit


    then i started adding shims till i felt no more side to side play, after tightening it up and checking, it needed
    six shims in total

    i added the pinion gear and started to move the shims over checking each time for play. Once it got too tight i moved one shim back to the other side, it ended up taking 5 shims on the one side and one plus the flm one on the other side. once bolted up the gear mess turns and feels nice and smooth
    The smartest person, asks the most questions...

  37. #37
    RC Competitor
    Join Date
    May 2013
    Location
    Texas
    Posts
    74
    Very nice! You also put some grease on the ring gear, right?

    Typos courtesy of Swype

  38. #38
    RC Qualifier
    Join Date
    Aug 2012
    Location
    Albany, New York
    Posts
    463
    Does anybody know where the little red rubber o-ring goes inside of the Differential Cup in the FLM Ultimate Hybrid Bulkheads, I seem to have two of them little rubber red O-rings from both my front and rear FLM UHB so im wondering where the place place would be to house them?

  39. #39
    RC Qualifier
    Join Date
    Aug 2012
    Location
    Albany, New York
    Posts
    463
    While I'm at it, can anyone also clarify with me on the fact that the two bearings that rest on the pinion shaft should be faced so that the yellow seal face inside of the diff cup and the silver sealed part of the those two bearings should face outwards, towards the transmission?

  40. #40
    Marshal ksb51rl's Avatar
    Join Date
    Nov 2006
    Location
    Northern NJ
    Posts
    15,722
    This is an aftermarket product support thread and as such it is now closed.
    Alt-248 on the number pad =

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •