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dddlin

Transmission Fluid Leaking From Vent Cap

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Our 1998 Newmar Dutchstar, 153k miles, is leaking transmission fluid thru the vent in the cap.  All hoses seem okay.  Tank does not appear to be overfilled.   RV runs great.  No warning lights, all gauges are normal. Any suggestions?

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What is the fluid level look like on the dip stick when the engine is running?

When was the transmission last serviced - filters changed?

 Might draw off a little of the fluid and see if by chance there is some coolant mixed in with it? Can do that by pouring some of the lubricant from the filter into a clear container and letting it set for a time.

Rich.

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Have you checked fluid level with the shift pad (assume this is an Allison 3000 series transmission)?

And, by vent cap, do you mean the dip stick tube or something on the transmission?

I agree with Rich, make sure you do not have coolant in transmission/ATF in radiator.

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2 hours ago, dddlin said:

How would the coolant get mixed with the transmission fluid?

The transmission is cooled by a cooler plumbed into the engine cooling system and should a leek open between the cooler and the antifreeze,cross contamination can happen. Making extra ATF or Coolant is never good good and needs to be addressed. Not an impossibility as things age. 

From your post, it sounds like someone might have over filled a hydraulic reservoir as Bill mentioned. Allot easier to deal with then the above items.

Rich.

 

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Agree-- what is the level in the hydraulic reservoir on the dipstick.  Overfilling when cold will expend when hot and can certainly overflow. 

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So I need to check when it is hot? After it runs for a while?  And can you tell me if the the reservoir in the rear feeds the brakes?  Is it separate from the jacks? 

BTW, thanks for your patience.  I figure you are shaking your head at these dumb questions.:wacko:

Linda

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46 minutes ago, dddlin said:

So I need to check when it is hot? After it runs for a while?  And can you tell me if the the reservoir in the rear feeds the brakes?  Is it separate from the jacks? 

BTW, thanks for your patience.  I figure you are shaking your head at these dumb questions.:wacko:

Linda

There are no dumb questions from my point of view ! We are all on a learning curve regarding Motorhomes ! Just when you think you have seen it all, something new pops up.

So just fire away. Everyone on this forum wants all to enjoy there RV and be safe. 

Safe travels Rich.

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The hydrualic for the power steering or the levelers? Sounds like the power steering. Is the fluid clear or black? If black the pump may be sucking some oil from the motor. If it shows air bubbles it may be the suction line between the res and pump.

Gary

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Gary/ I was about to chime in. We have the same reservoir viewable when I lift the rear grill. Always thought that it was for the power steering pump. Hope that I am right. Level stays constant, and the levelers work just fine.

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5 minutes ago, obedb said:

Gary/ I was about to chime in. We have the same reservoir viewable when I lift the rear grill. Always thought that it was for the power steering pump. Hope that I am right. Level stays constant, and the levelers work just fine.

VERY, VERY likely the reservoir in the very back is for power steering, NOT jacks.  Don't know what brand jacks you have, but all I have worked on have their own built-in reservoir with no filter.  Many of the PS reservoirs also have filters in them-- yes, they need to be changed.

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Yes Byron, mine has the same same one that you can see the fluid in and I have never had to add either.My HWH is in the front above the genset. I did have to add a tiny bit to that one. And Brett is right about the filter in the reservoir and with that many miles probably should be changed.

dddlin,

If you have a dipstick and it is on the top of the resevoir, you should be able to take the top off to get to the filter. Just make sure the new filter has the same sealing sufaces and get the spring and washer back on the top. The outer diameter might be a little bigger or smaller but the length should be the same.

Gary

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I forgot to mention, not to many power steering fluids are red, has someone added transmission fluid to the steering. Not the end of the world, but steering fluid is best.

Gary

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OK, lets cover how to change the filters on the hydraulic reservoir.  Main thing is to NOT just remove the over and reach into the oil and remove the filters.  That will allow the unfiltered oil to get "past" the filters and go straight to the pump.

SO, buy 5' of cheap 1/2" or larger ID clear plastic hose. Remove the lid.  Use the hose to siphon off all the fluid from the outside of the filters.  THEN, remove the filters.  Replace filters and fill with the OE spec'ed fluid.

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7 minutes ago, garyreed said:

I forgot to mention, not to many power steering fluids are red, has someone added transmission fluid to the steering. Not the end of the world, but steering fluid is best.

Gary

Actually, best advice is to VERIFY what the OE fluid was for your coach.  One of our DP's used Delo 400 15-40 for hydraulic fluid.  Add ATF or power steering fluid and you would really screw it up!

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If it has a steel resevoir it may have a drain plug. In the mid nineties PACCAR products recomended 15-40 in their units, the feeling we had was that it kept the driver from buying oddball fluids on the road. most carried motor oil. I agree with the OEM, the dipstick may give the recomended fluid.

Gary

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HWH jacks use either their own fluid or Dexron.  The difference is that HWH's fluid is clear, so won't stain if it leaks.  But Dexron works just fine (the red colored stuff).

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