Results 1 to 8 of 8
  1. #1
    RC Enthusiast
    Join Date
    Nov 2020
    Posts
    27

    Merv Differential Oil

    Hello,

    I was disassembling my merv to clean and dry it after a run, and I noticed that my rear diff looked like it had very little oil. How much oil is it supposed to have, and how do I know when to refill it?

    Iím also looking for recommendations for oil weight, I mostly drive on dirt and off-road, and Iíve never changed out diff oil, so any recommendations help. (In case it matters, I donít have the center diff, and I run Proline Trenchers).

    Thanks in advance.

  2. #2
    RC Racer
    Join Date
    Sep 2015
    Location
    Minnesota, US
    Posts
    118
    If you don't have a center diff and you are running lipos I have no idea how you haven't managed to blow out the rear diff. I personally run 10k front, 30k center , and 50k rear for fluid weights. I fill the diff up to just above the planetary gears. If your diffs are leaking I would get a rebuild kit to get new o rings because that shouldn't be leaking. If you go to 9:18 in the video I linked it shows about the height I use for fluid.

    https://youtu.be/Gnq6PQ2nDpg

    Sent from my SM-G973U using Tapatalk

  3. #3
    RC Enthusiast
    Join Date
    Nov 2020
    Posts
    27
    Ok, thanks for the advise. I probably should have clarified, but I don’t run LiPo yet, I’m probably going to wait until spring when I’ll actually be able to run the merv more often. And when I do run LiPo, I’m thinking about just shimming the diffs.

  4. #4
    RC Champion Acidic01's Avatar
    Join Date
    Jul 2018
    Location
    beaverton oregon
    Posts
    1,971
    I run 150k front and rear in min as I like a more locked diff on my car.

    No center diff. As I don't use that car a lot as xmaxx gets all the play time. But do run 3s on it.

    Sent from my Pixel 3 XL using Tapatalk

  5. #5
    RC Qualifier
    Join Date
    Jun 2020
    Location
    Texas
    Posts
    427
    The diffs should be "Full", however when you pop them open, a full diff will have some open area in it to account for the final gears in the end you just took off. If you feel like its not full, then dissemble, remove all old fluid and refill with your choice. The stock diff fluids are 50k wt Front, 30k wt rear. If you have the center diff, it comes with 50k wt diff fluid.

    Personally, I run it with stock weights as they work well for me. I also have the center diff, which helped out quite a bit. I run nothing but 3s.

  6. #6
    RC Qualifier Calebs0615's Avatar
    Join Date
    May 2020
    Location
    Maine
    Posts
    982
    Im not sure the diffs are supposed to be full.. The fluid has to have a place to move around when the parts inside are turning. Typically i put in between half and 2/3 fluid. If you overfill the fluid will just come out wherever it can.

    Sent from my LGL722DL using Tapatalk

  7. #7
    RC Qualifier
    Join Date
    Jun 2020
    Location
    Texas
    Posts
    427
    Quote Originally Posted by Calebs0615 View Post
    Im not sure the diffs are supposed to be full.. The fluid has to have a place to move around when the parts inside are turning. Typically i put in between half and 2/3 fluid. If you overfill the fluid will just come out wherever it can.

    Sent from my LGL722DL using Tapatalk
    Do you do this to account for heat expansion?

  8. #8
    RC Qualifier Calebs0615's Avatar
    Join Date
    May 2020
    Location
    Maine
    Posts
    982
    Quote Originally Posted by halygon View Post
    Do you do this to account for heat expansion?
    It could be, but also so that the fluid can circulate on its own amd go where it needs to. Naturally the differential gears are going to move the fluid around and if you have it full to the top, the fluid wont move throughout the differential. It just sort of sits there and doesnt fill the spaces as it moves. The spinning action throws the fluid.

    I bought the hot racing sealed diff for my 2wd slash and filled it with 1m fluid. (Maybe 2m i can't remember) Well literally after the first run I was putting the truck away and noticed thick fluid leaking around the output yoke seals. I took it apart cause i thought the seals may have moved but when i took it apart, it was fine. I refilled and ran it again and it did the same thing. I took it apart again googled something about over filling differentials so thats when realized it was from filling the diff completely. After only filling about 2/3 of the way from full i havent had any leaks or issues with gears.

    I did the same with my 4wd rustler and havent had a leak or any problems.

    Sent from my LGL722DL using Tapatalk

Posting Permissions

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