Excessive primary fluid question

Discussion in 'Transmission' started by coylizard, Apr 28, 2012.

  1. coylizard

    coylizard Member

    So I purchased an '88 FLHTC (Electra Glide) from a guy last October. He said he had just changed the primary fluid... and in preparing it for winter storage I changed the engine oil and transmission fluid.
    After several exhilarating rides this spring, I decided to check and change the primary fluid.
    When I removed the primary chain inspection cover today (with the vehicle upright and level) close to half a quart of fluid drained out of the inspection site! The primary had been over filled.
    There has been no apparent malfunctions... other than a regular slight primary leak... and I'm wondering if there are any significant ramifications from overfilling the primary.

    Have you any words of wisdom?
  2. 89stroker

    89stroker Active Member

    Have you found that your engine oil is 1/2 quart low? The reason I ask is that on an older EVO motor, engine oil can migrate from the engine crank seal into the primary when the seal starts to fail.

    I don't know if an overfilled primary will actually hurt anything, although it will put unneccessary drag on primary components.

    BUBBIE Well-Known Member


    89stroker is right on here. It would be hard to put enough oil into the EVO primary and most of the time IF Found that way, IT IS what he said about the problem of the older EVO models of the bike.

    A friend of mine had the same thing happen BUT was Low on oil in the engine, saying to me that IT didn't Burn oil and when he checked the primary, found it FULL like yours. Engine oil...

    He had to replace the engine /primary seal to correct the problem. Primary outer removed Clutch and compensator then the Stator to get at the seal on the engine shaft... Careful on putting on the NEW seal so the shaft Splines DON'T cut the new seal...

    I'd like to ask a question here to anybody having done this.

    MY Asked Question here???

    Has anybody done this job to Their EVO and Did you Double the seal in EACH direction on the engine shaft ??? to RE seal the shaft from leaking in and out? I have heard this being done but LONG Ago...:newsmile03:

    This MAY help you out with what to do....Let us Know please...:D


    My friends bike turned out to NEED new rings to stop the Blow-by to work GOOD again... even after the new seals it leaked some .... Check your compression and maybe do a leak-down test.Yours MIGHT need new rings AND NOT the new seal?
  4. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

    Unless things have changed, I don't see how this is possible. On my bike you fill the primary through the inspection opening so it would be impossible to overfill by as much fluid as you're describing. You could only get to the bottom of the opening and it would start spilling out.

    Much more likely that fluid is migrating into the primary after everything is buttoned up, as 89stroker has described.
  5. HDDon

    HDDon Experienced Member Contributor Retired Moderators

    Some really good advice here, and you do need to see if the fluid in your primary has come from the engine oil migrating. The answer to your question about if the excessive fluid will cause problems is yes. To much primary fluid can make it hard to find neutral and cause the clutch plates to stick together.
  6. coylizard

    coylizard Member

    Thanks for the comments and recommendations. I appreciate every word.

    I just checked the oil level and the transmission fluid level and found them to be full.

    While I appreciate that one could not over fill the primary by adding fluid through the primary chain inspection site, I wonder if the previous owner may have filled via the clutch inspection site. The gasket at the chain inspection site was found to be old, damaged, and difficult to remove.

    The fluids levels are now as recommended. I'll wait, watch, and respond to any future issues.

  7. Dr. Dolittle

    Dr. Dolittle Experienced Member Staff Member Moderator Contributor

    This is why I said, "unless things have changed." They obviously have. My 2008 FLHX only has the one cover/inspection opening that is used to adjust the clutch and fill/inspect the primary fluid level.

    The set up as you describe it could very well lend itself to an overfill situation.

    Let us know how she rides now that you have all the levels correct.
  8. Jack Klarich

    Jack Klarich Expert Member

    88-90 engine cases were noted for this problem as well as the cylinder studs loosening up and fractures to the case where the studs go in, H D recalled alot of these motors but I am sure a few of them are still out there hope yours is not one of them
  9. Lawdog314

    Lawdog314 Active Member

    Did my 2010 Ultra. When I took off the inspection plate. Old oil right to the edge, drained fluid, then added 32 oz guy at parts desk said it needed. I can see fluid at the bottom of what i think is the clutch basket. Book said that was "adequate".

    Leaves me scratch-en me head since the book later says 38 oz. :panic

    Short ride seemed fine...

    Any pointers my friends.

  10. Jack Klarich

    Jack Klarich Expert Member

    38 oz may be a type o if the bike is level and fluid is at the bottom of clutch basket you should be OK, if you could get the extra 6 oz in and the clutch does not slip probably be OK