JLeatherman

I purchased a Ford FMX filter and it came with a grommit in it. Haven't tried it on the tranny yet, but it sure looks right. I'll get some pics over the weekend or something if it's the right one.

ACECO

As stated above I did a fluid change to both the 4 speed and OD sections of my 4+3. Here's what came out of the OD unit:



Now while it didn't look quite as bad as it appears in this pic, it was dirty. However no burnt smell and the "lubricity" seemed about right using the highly accurate "rub it between your fingers" test. But regardless I'm really happy it's no longer in my OD unit.

Here's a pic of the removed filter:



I noted that even though the fluid was quite dirty, not much of anything that can be seen is appearing in the filter. I did have a new filter and did install the new one, but I'm not sure why the old one couldn't have been cleaned up and reused. Now before anyone flames me about changing a $6-8 filter when the pan is off being no big deal, follow me while I return to the "adding a drain plug" thread I had read about elsewhere.

http://www.theforumlounge.com/thread...ification.html

While I didn't add a drain plug this time, based upon what I found in my OD unit I'm not so sure this isn't a good idea. I'm certainly NOT suggesting you never replace the filter. However with the large surface area of the filter and regular changing of the ATF, I think adding a drain plug would allow more frequent service w/o nearly as much hassle. And by lengthening the time frame between having to drop the pan, the OD might actually get more attention and thus better overall service, at least in some cases. Unless your OD is "coming apart" and spewing out bigger chunks of "filterable" material, I'm now of the opinion that the filter could easily go 25K miles, or more, as long as you keep clean fresh ATF in it. And of course if your OD is spewing out bigger chunks, then you likely have bigger issues than the filter.

Of course as with all projects and opinions, YMMV. I'm certainly open to comments and other opinions on this subject as next time I have to drop the pan, I may very likely add a drain plug.

Last comment on the OD fluid/filter change is that it seems to have helped the minor issue I was experiencing. When I shift from 1st to 2nd I would release the clutch and about 25% of the time a moment later the OD would then engage. The other 75% of the time it would engage normally. Or what I believe to be normal which is that it "instantly" engages when the shifter is pulled between 1st and 2nd, and before the clutch is released. So far it hasn't once "paused" before engaging since the fluid change. I haven't driven it too far yet so this issue may still be there, but it seems much better thus far. FWIW.


Lastly, here was the most "disturbing" part of the afternoon. As I mentioned I also changed the fluid in the 4 speed section. Here's what came out:



Only about 5/8 - 3/4 of a quart came out and it was a lovely shade of baby poop brown. The only other time I've seen anything like this is when an old Hyundai I had years ago blew it's head gasket and water got into the oil. So I'm not sure what I was looking at here beyond what was likely left of the original 23 year old factory gear oil. But regardless, I'm really really glad this isn't in the trans anymore! I refilled the trans with about 1 1/4 qts of fresh gear oil and I'll have to say that much of the balky shifting issues I was experiencing have disappeared.

Again I hope this helps someone going forward.

Good luck w/your 4+3 adventures.

CentralCoaster

Which brand?

CentralCoaster

That 4-speed oil looks like water got into it.

Whats on the drain plug is more important.

The screen does seem pretty useless for a filter. Some brands I checked offer a paper filter, but I only found one that showed it coming with a grommet, it was an old off-brand.

The filter in the 700R4 in my truck is paper. I really don't see the point in a long lasting filter, unless GM intended that to last 100,000 miles or something. The more you look into it, the more you begin to think GM didn't really think about it to begin with.

ACECO

It sure does look like water was mixed with it. Not sure how this would have happened unless the trans was submerged. However I guess anything is a possibility in the 20+ years prior to my ownership.

The drain plug did have some "sludge" on it. I know that wasn't the best sign. However what were you thinking when you made this comment? Sludge or something else? Let me know.

I agree that the screen filter seems at best minimally effective in this application. This is why I think a drain plug would be a good idea. If it let's you much more easily drain off the ATF and change it, then I think this is a better choice than putting off the service because someone doesn't want to drop the pan for whatever reason. Again just my opinion and FWIW.

While the corvette is a wonderful vehicle in many respects, I'm am not naive enough to believe that GM didn't "screw up" here and there and may not have done the best job that could have been done on any particular design. And in this case I'm not even sure it was GM if the complete unit was sourced from Doug Nash. They just found a filter that was commonly available "off the shelf" that fit and would work, and used that. I'm sure no thought was given as to what the consequences were going to be 10 years later, much less nearly 25. Overall it is what it is, much like lots of other things in this life. But I will say that all of this has left me with the opinion that at this point 10K mile filter changes are overrated. However the fluid changes are whole different story. The more often you do this, the better off your going to be IMHO. Oh yes once again, YMMV.

ACECO

I'm in NJ so it would have to go coast to coast. Use 07885 for any shipping calculator lookups.

At this point I'm not so sure what I have isn't "good enough" for now. After draining and replacing the gunk that came out of the trans with the proper amount of real gear oil, most of the balkiness has disappeared. However I'd still like to convert my console OD switch to on the shifter. Do you know if the main shifter lever that holds the **** is hollow on your 85? (for the wire to pass thru) If whatever you have can be used to convert what I have on my 84 by swapping parts but not the whole shifter, then I'd still be interested. Let me know your thoughts.

Thanks CC. Appreciate all your input and help!

ACECO

One more thought came to mind in reference to the OD fluid change. I read where you have to fill the OD and then rotate the rear wheels. After that more fluid can be added. As I had the car up in the air like so:



I couldn't rotate the wheels after first filling the OD. So I took it off the ramps and drove it around the block. Put it back up and was able to add approx 12-14 ounces more fluid before it again was running out the hole. As the FSM doesn't mention this additional step of rotating the wheels, I'm not sure which level is the correct one as I could see where both too little and too much fluid could be bad. But in this application, and with the limited amount of fluid in the unit to start with, I opted to go for the "more is better" mentality in this case. Again FWIW.