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Oil blowing out trans vent tube

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bigbubba402

Active Member
Ok I got a call from a bud he is on road trip up northern Michigan on a 99 ultr at speeds over 65 mph he is blowing oil out of the trans vent tube he put a longer vent tube on and seems to have slowed it down.Then he proceeds to tell me that it is engine oil coming out.I told him that the engine /trans are seperate units.My question is how could engine oil be coming out the trans vent? He has a locale shop do the oil changes so he has hd oil's in all 3 holes.
 
Engine oil can migrate to the primary but not to the trans. Possible the service overfilled the trans.
 
One point if it is HD oil in all 3 holes it could quite well be that it is engine oil in the gearbox and therefore any oil coming out will be engine oil
however is it that engine oil level is going down as the oil comes out of the gearbox

Brian
 
correct he said his engine oil was going down at the same time as blowing out the trans vent.That is what blew my mind
 
bigbubba402 said:
correct he said his engine oil was going down at the same time as blowing out the trans vent.That is what blew my mind
Click to expand...

The TOP of the tyranny and the Engine oil tank SHARE a "top" opening,,,, SO Fluids from the engine tank COULD merge with the tyranny..

On my 2000 fxds the oil goes Thru a Opening area that CAN leak into the tyranny.. The TOP gasket cover must be Bad for the tyranny to get extra oil... Easy enough to check...THE Tyranny level HAS to be HIGH as IT WILL seek the proper level and that is what it is doing,,OUT THE Vent Hose....

I would NOT impede the tyranny getting rid of EXCESS oil as you can blow another seal..I would Remove the longer hose and IF he doesn't get it fixed soon Engine oil is all it is going to be.. Maybe that is all that is there in the first place???

Darn HD and 3 holes into ONE.. Never good.

signed....BUBBIE

Take a look at the break-down and you will see the engine oil pan is connected right below the tyranny..

signed....BUBBIE
 
BUBBIE said:
The TOP of the tyranny and the Engine oil tank SHARE a "top" opening,,,, SO Fluids from the engine tank COULD merge with the tyranny..

On my 2000 fxds the oil goes Thru a Opening area that CAN leak into the tyranny.. The TOP gasket cover must be Bad for the tyranny to get extra oil... Easy enough to check...THE Tyranny level HAS to be HIGH as IT WILL seek the proper level and that is what it is doing,,OUT THE Vent Hose....

I would NOT impede the tyranny getting rid of EXCESS oil as you can blow another seal..I would Remove the longer hose and IF he doesn't get it fixed soon Engine oil is all it is going to be.. Maybe that is all that is there in the first place???

Darn HD and 3 holes into ONE.. Never good.

signed....BUBBIE

Take a look at the break-down and you will see the engine oil pan is connected right below the tyranny..

signed....BUBBIE
Click to expand...

Bubbie if I remember right 02 models had problems with the oil lines and the innerface with the engine case and the tranny where they bolt together, the factory did nit put sealant on the oil line threads causing some to have major leaks, this could explain the oil on the top of the tranny:s
 
Update I got a call and it appears that he had put a new air cleaner on and that had somehow blocked or sent pressure into the engine somehow? Anyhow he had his old ac with him and changed it back and had the trans and engine oil changed and it is doing good now.When he gets back I will try to get a look at this and update thanks for the input
 
Bubbie,Are you refering to the top cover on trans that is held on with 6 bolts?He is still having issues he did get back home and at 80 mph is still putting engine oil into trans then out thru the vent.by taking the air cleaner off it helped (i know should not run it that way either) at least he was able to get it home but it still blows out the trans vent tube.
 
On a '99 FLHT the engine crankcase is vented to the trans then to the outside air. The hose exits the engine just to the left of the rear lifter block and enters the trans in front of the top cover close to the shifter linkage. That is the oem setup according to my parts manual (I own a '99 FLHT).

It is possible for the engine crankcase/blowby to mix with the trans oil. I know this because I use to run Royal Purple in the trans and it always turned semi black quick. I don't know if enough oil could transfer to make it blow out the trans vent tube though. I do know that times when I run my bike pretty hard (80+mph for over a hour) the vent hose would sweat oil around the fitting going into the trans. I have since then updated to the newer style that vents the engine to the oil filler neck. Hope this helps.
 
That all kind of makes sense so the crankcase breather is into the gearbox and then out to the big world from there
so there is oil coming from the crank case breather first thing to check for me in that case is compression if the rings are not a good fit some of the combustion pressure can blow past the rings and pressurise the crank case and throw oil out of the breather
the faster the engine runs the quicker the oil comes out

Brian
 
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