Fluid leak

[Captain Paul]

I noticed the other day a large puddle of what appears to be ATF fluid underneath my MH. I haven’t had much time to investigate yet but I took some pictures and thought I would post it to see if anyone else has run into this same problem. Thanks!

[BayouBiker]

Yeah the rear transmission shaft seal is leaking. Age and heat makes them brittle and a slight wobble accelerates the process. It is not particularly difficult to replace once you have the drive shaft and harmonic balancer removed. There may be a nice youtube video to help you. Otherwise any reputable auto repair shop can do it.

If the leak is not bad, and your transmission is otherwise in reasonably good shape you can sometimes get 2,000 to 10,000 more miles out of it with transmission seal leak repair. It softens and conditions the rubber a bit and often but not always allows the seal to function, sometimes it makes it worse. It's a crap shoot, and many will advise against this approach due to various risks of putting additives in the transmission fluid. The conditioner won't affect the torque converter, bearings or clutches, but it will affect every internal rubber component (there aren't that many fortunately) so, I'll let you use your judgement.

[bobmiller1]

With the ATF slinging around you have a very good chance of the motor home catching on fire.....the ATF is bound to hit the exhaust pipe and then poof.....there goes your motor home while you are driving it and the fire is being fanned by 30-60 MPH winds. Get it repaired right away and steam clean any residual that you can see like what’s in the picture. Regards, Bob

[BayouBiker]

It's good to be concerned about that but not too crazy alarmed, a properly operating exhaust with converter will hover around 650F and ATF ignites at 900 on a hot metal surface when it is not being bathed in new fluid continuously but a plugged converter can exceed 1100 F so Bob's caution is warranted.

[Captain Paul]

Thanks for the info. I will let you know how the repair goes.

[Captain Paul]

Just finished replacing the transmission output seal.
The big Takeaway is… If you notice on the picture there’s a lot of grime above where the transmission break is located. Way more than would normally come off of the grease from the universal joint. If you notice this you may want to think about replacing the transmission output shaft seal sooner than later.
It is not particularly difficult to do. You will need to unbolt the driveshaft where it connects to the transmission but you do not need to remove the entire driveshaft. Next the vehicle will need to be in neutral for you to pull off the drum for the transmission break. Obviously chock the vehicle! Once it’s done there is one bolt in the center that needs to be removed in order to access the seal. You definitely want to use a seal puller to remove the seal. Also I would recommend taking the seal with you to the auto parts store to ensure you get the correct replacement part. Then it’s just a matter of tapping the Seal back in place and putting everything back together. This was also a good time to you grease all the fittings on the driveshaft for some quick routine maintenance.