Greetings all,

I'm getting ready in the next week or so to change out the fluids in my 84's trans, OD unit and diff. While researching on the net, I found the following thread on another forum about adding a drain plug to the OD pan.

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

I like the idea of being able to change the fluid on a regular basis w/o having to drop the pan, but I was wondering what the general thoughts were on adding a drain plug as shown in the above thread. I already have the drain plug, fluids, filter and pump to get the liquids in and out, but am waiting on a nice day to perform the tasks. While I'm waiting, I thought I'd get some other opinions.

So with that, what is your opinion of the adding the drain plug and specifically the method shown in the thread using RTV, etc?

TIA to all who respond.

 

Don't bother with the ovedrive drain plug. The filter should be changed out anytime the overdrive fluid is changed.

I'd do it about every 20K for normal usage.

Use "The Right Stuff" rtv to seal the pan, do not use a gasket.

Filter can be purchased locally:

Carquest # 85926
AC-Delco #: TF184 ($4.50 at Rockauto.com)
Fram #: FT1024 ($9 at Kragen)
Napa #: ATP14717 ($8.50) or ATP14629
Ford #: D0AZ-7A098-A
General Motors #: 12339143

Reuse your stock grommet if it's fine. Do NOT use an electrical grade grommet (like what's sold by Ecklers.)

More info on that here:http://forums.corvetteforum.com/show....php?t=1079461



Any old 75w90 gear oil will suffice in the trans and rear end. Don't get crazy with synthetics back there if you think there's a possiblity of exposing oil leaks. I don't think there's any benefit to synthetic in there.\

Trans takes about 1.5 quarts, rear end takes not quite 2, so buy 4 quarts, and 8 oz of limited slip additive.

 

Thanks for your input CentralCoaster.

The only reason I was thinking of the plug was to change the OD fluid w/every oil change thus hopefully increasing the time between filter changes. However I suppose as I have only done approx 5K miles per year so far, that puts the next service at least a few years away. Guess I'll worry about dropping the pan again then.

The right stuff RTV, huh? I have three tubes of Permatex RTV, blue, red and copper. I was hoping one of these would do. Any additional thoughts on why the "Right Stuff" is better than one of the ones I already have?

I will attempt to reuse the old grommet but have a electrical grade version as a backup. I understand it may get gooey and loose it's seal causing no OD, but if the stock one isn't usable I'm not sure what other alternative there is at the moment. If you have a part number, etc available for a better grommet choice, please let me know. I will be careful with the edges of the tube and may even take a small jewelers file to remove any burrs or sharp edges if found.

Lastly I will be using Lucas 80W-90 gear oil for the trans and diff. I have had very good experiences with their products. Their gear oil says no posi additives needed but I have some anyway. When I did the diff on my 75 a couple years ago, I added the posi additive anyway and all seems well. So based upon that, this is the plan for the 84 too.

Oh yes, one more thing. I have had so much success using Lucas Trans Fix additive in many compact car automatic transmissions that I'm tempted to add 8 oz or so to the OD ATF. My experience is that this stuff really works and makes an older trans operate much smoother overall. Thus I figured it couldn't hurt in this application either. Any thoughts?

Thanks again for your input. It is appreciated.

 

Dunno on the additive, I've never used any additives in anything, but haven't had a whole lot of cars either.

The Right Stuff is just plain as good as it gets, everyone should have some on their garage shelf (and kitchen cupboard). It is better than perhaps every single other RTV. (btw blue and red are crap, copper is good for really hot stuff, exhaust)

The easiest thing for the grommet would be to just order it online. mcmaster.com has them in different types of rubber. Someone said Buna-N would work well. I think silicone would work well also. You might have to buy a bunch of them, but imagine all the friends you could make by sending some extra ones out in envelopes to your corvetteforum friends.

There seems to be some disagreement on what size. The one I mentioned in that thread is what I used and it seemed like a perfect snug fit. The ecklers one was close but had too big a gap. If all else fails, measure your pickup tube and filter hole.

http://www.mcmaster.com/

search for "rubber grommets"

 

OK I'll pickup some "Right Stuff" for the pan. I don't want to have to redo the pan because it leaks so what's another few bucks. In for a penny, in for a pound.

And speaking of this, I did a search on the McMaster Carr site and found the grommet that was referred to in the old thread. Got the Buna Rubber ones and had to buy 10 for approx $6, but now I have a lifetime supply. And because there seemed to be some debate on which size was right, I also picked up some of the slightly smaller sized ones you indicated. Now these came 50 to a bag for approx $9.00. So assuming these will also work, I now have a couple of lifetimes supply.

And as to your "make friends and give some away" comment, I usually hang out in the C3 section as the C3 is the "toy" vs the C4 which is more of a driver. Whenever I post a question over there I get lots of responses. Based upon this thread, apparently not so much here. However I bet if I start a thread indicating free overdrive grommets, I'd get more than one person responding.

If you want a couple grommets when I get mine, I'll be more than glad to send you some. I really appreciate your input and comments. As for the rest of the grommets, perhaps I'll try and sell some on ebay.

Thanks again CC. I'll let you know how I make out. And also let me know if you want me to send you a few grommets.

 

Please let me know which size fits.

As for the responses, you got all your answers within an hour. There's quite a few people that like helping but don't have any answers, luckily you didn't have to sort through any of that b.s..

I'm done with these 4+3s, although I do have one in the shed that needs some new seals before I can sell it, I'll let you know if I need one for the overdrive.

 

Will do. Based upon all I've read, I suspect both will work but one will fit better than the other. However I will let you know what I find out when when I get under the car, hopefully this coming weekend.

That is true. I suppose a response from one person with all good info is better than getting dozens of 's or the like. However I was a bit surprised that I didn't get any other comments/input from anyone else besides you. Oh well, again I certainly do appreciate what you have provided.

I noticed that you indicated a 6 speed under your info and was wondering just how much of a chore this was to install in your car? I have thought about "upgrading" to a later model C4 w/a 6 speed as this is the only thing I really wish my car had. However after doing some shopping and weighing the gains vs the costs along with knowing my car is in good shape and has the Z51 suspension, I have recently begun thinking about a 6 speed swap. Could you tell me a bit more about what was involved and if it is a direct bolt in w/the right parts?

Thanks again Kevin. I do appreciate it!

Regards................George