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aw4 leak from where?

DeftwillP

DeftwillP

NAXJA Forum User
Location
Round Rock TX
I've been leaking transmission fluid for sometime. I have replaced the shaft output seal(2wd) a few times and I know that this is currently one source of a leak.

But I noticed something unusual while laying underneath the heep earler. There appears to be fluid residue from it being "sprayed" on the underbody along the passenger side of the transmission. The spray pattert starts just behind the NSS and goes as far as the output cone. It just doesn't seem that a leaking output seal would cause the fluid to spray that far forward.

The cooling lines appear to be in good shape and have no leaks coming from them or where they meet the trans. I took a look back at the passenger side shock and there is a thick layer of trans fluid and dirt on it as well as all over the rear axle.

Aside from constantly having to top her off, I'm getting tired of degreasing the back hatch to take the oily spots off. I also don't want to risk trans failure.

Any ideas?
 
There are, as I recall, four main seals on the outside of the AW4. The rear output (which you've changed,) the front pump seal (behind the torque converter,) and two "shift shaft" seals (on either side of the box.) No other seals (again, as I recall,) are subject to relative motion.

The shift shaft seals are difficult to replace, and I haven't yet devised a simple way to do it (I haven't had to yet,) but I'd imagine that a small screw could be used to grab the seal and pull it loose, and some care could be used to drive the new ones in. This would, potentially, allow replacing those seals without an overhaul.

I am also not yet aware of those seals coming in anything other than a rebuild kit - but I haven't had to look.

There are a couple other seals, but they are not subject to relative motion between parts, and are probably not subject to failure over time.

Hope this helps.

5-90
 
Thanks Jon. That's pretty crappy news.

If I provided a pic, would it be any easier for you to diagnose? I don't have a digi, but I can work something out.
 
I could take a swat at it - if you can, clean everything up, run it for about 10 minutes, and spend about a minute in EACH gear range, to circulate fluid. Idling is OK.

Check after that - if there are leaks, take pics of some sort. If not, go for a short drive, and load the transmission.

Send me whatever you can, and I'll see what I can do with it. No guarantees, but "fresh eyes" should be some help...

5-90
 
5-90 said:
I am also not yet aware of those seals coming in anything other than a rebuild kit - but I haven't had to look.
Click to expand...

Rock Auto lists them as BCA #221207, although it shows "Aisin 30-40FL" as the transmission. The description, with diameters, looks to be about right. About $3 each.

Ours could use them (they weep in cold weather), but I haven't tried to replace them yet. They do look like a booger to get out of there...
 
I've got to get a BCA or a CR book - I've got Timken, but they're mostly driveline stuff...

I'm inclined to think that you could get a "bite" on those seals using a #4 wood screw, or maybe a #6, and pull on that. The shells and lips of those are usually plastic - they don't hold a lot of pressure. Granted, I haven't tried it on those specific seals yet, but I've done it with good luck on other applications.

Worst case, drill a pilot hole, grind the end of a wood screw flat, and use it as a "screw ram" against the bottom of the seal bore - if you drive it in and it stops, there's something there to bear against.

The one behind the NSS should be fairly easy to get to once you get the NSS out of the way - I'm not so sure about the one on the other side. I just don't recall the arrangement of the shift shaft offhand - if there's a lever arm, then it depends on whether it's bolted on or welded.

5-90
 
On our Mopar '94, there's a nut holding the lever on the left side (just like on the right/NSS side), so it ought to be removable to get at the seal. There is not an abundance of room to work with, though.

I think your wood screw idea ought to work. I'd want to examine the new seal first before going after the worn one.
 
The wood screw idea does work - I've used it probably a half-dozen times in the last 30 years. Learned it from my granddad - who saved two day's downtime on a machine by welding together a 6' welding rod once upon a time... I've learned much from that man, and I honour his memory by using it and disseminating it widely...

The nice thing about using #4 or #6 screws is that they can be had fairly short - so if you've not got a lot of room, that comes in handy...

5-90
 
For most seals, I run a sheet metal screw into it and use a prybar on the screwhead. Seems to work much better than prying under the lip of the seal, especially if the shaft is still there.

Have you looked at the cooler lines really well. There is a clamp off the bell housing that may rub through the lines and weep.
 
Well, I'm having a hard time sourcing a friend with a digi cam. I'm gonna look again tomorrow and double check lines and gasket edges. I'll try going heavy on the degreaser to start from scratch. If nothing else, when I'm doing maintenance week after next, couldn't I drop the pan, clean the screen, and bolt her back up? Are the pan gaskets known to randomly go?

Also, is there any kind of dye kit that might help me pinpoint the exact location?
 
[
The shift shaft seals are difficult to replace, and I haven't yet devised a simple way to do it (I haven't had to yet,) but I'd imagine that a small screw could be used to grab the seal and pull it loose, and some care could be used to drive the new ones in. This would, potentially, allow replacing those seals without an overhaul.

I am also not yet aware of those seals coming in anything other than a rebuild kit - but I haven't had to look.


I have a leak at the shift shaft seal and I'm also tring to figure out the best way to replace without splitting the case. The service manual shows a bushing and an O-ring, not you typical metal lipped seal. This is on a NV242 case though and I don't know about others models. I was thinking of maybe pulling the case and removing the front yoke. This would at least allow some room to work. Otherwise tring to remove the o-ring is going to being a real pain. Hopefully someone that has done this before will chime in.

Dave
 
Sorry for a late reply, but I though you would like to know this Jon.

I was working on my heep a week or two ago. I went ahead and replaced the rear output seal AGAIN, but put RTV on it this time. While looking around, it seemed that fluid was coming from the speedo sensor location. Even though fluid was splashed against the passenger side of the underbody, the only visible leak on the actual trans was from there. I pulled the sensor and sure enough, the o-ring on the sensor housing was missing a section of nearly an inch long!!!

After replacing that and haven driven it for over 500 miles, I seem to not have the oily deposit on my rear hatch anymore and my fluid level seems to be a constant now.

So Jon, you might want to add the speedo sensor o-ring to a potential problem on the aw-4 for anybody that has replaced the sensor.

peace out
will
 
I sure don't. But they looked it up on the comp. at 0 reilly. It is under trans parts. Kinda hard to find.

If I'm not mistaken, they didn't even have one listed for the aw4, so I grabbed the one listed for the grand's tranny. Weeks later and no leak. I'll bet that the speedo gear holder thingee is the same size, i.e. same ring size.
 
I have the same mysterious leak. In looking at the Aw4 manual, the speed sensor seems to be located on the tailcone, do I have to drop the tranny, the manual doesnt have great pics.
 
GreenXJ2K said:
I have the same mysterious leak. In looking at the Aw4 manual, the speed sensor seems to be located on the tailcone, do I have to drop the tranny, the manual doesnt have great pics.
Click to expand...

Doesn't that sensor only exist on 2wd versions?
 
dlarrivee said:
Doesn't that sensor only exist on 2wd versions?
Click to expand...

There are two that we have to think about...

1) There's the "output speed sensor" which is on 4WD versions as well - it's a magnetic sensor in the transfer case adapter housing.

2) There's the speedometer pinion gear holder, which is going to be at the final drive (2WD tailcone, or 4WD transfer case tailcone.)

Both, IIRC, are actually sealed with O-rings as 'splash' seals (vice the normal lipped "wiper" or "pressure" seal.)
 
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