[Sirrotica]

Under the tail shaft should be fine, might be a good idea to block it rather than just trust the jack as there is a definite pinch point for fingers.

Exhaust systems usually have a little flex in them because the are mounted in rubber mounts. you can possibly flex it with a big bar or a jack against them. I have no idea if that would gain you enough room to get in to the access hole, been about 55 years since i owned a 56. If that doesn't gain you enough you'll likely have to at least loosen/remove the pipe up to get access.

Good luck........

[Parkman51]

I did manage to get on those bolts with a combination of inventiveness and a flex extension drive. Now that I know where to jack the transmission I'll give it a go... I also think I'll shorten the mount bolts 1/4 inch or so on the side where the exhaust pipe is - I had to use a deep socket for the more accessible nut. The less accessible nut, thank heavens, worked with a normal socket, otherwise it would have been exhaust surgery for me. Shortening the bolts a touch should allow me to crank the nuts down nice and tight with a regular socket.

Second update: I was actually able (with the same combination as above) to get the remaining pan bolts out without jacking up the transmission - BUT the pan still won't come out. It's caught between the same crossmember and something inside the pan, so I'll still have to jack the transmission to get it out.

That's tomorrow's project if I can arrange it. Will post an update! There's a local car show coming up this weekend, and if I can get this stupid gasket replaced (it'll be easy, they said, simple job, they said) by then I'll take her out to the show.

[Parkman51]

There are jobs that take 3 or 4 times longer than you expect, and then there are jobs that you wish had only taken that long.

I did jack the transmission up (screw jack and a block of wood under the tail shaft) and still somehow ended up having to unbolt one side of the frame crossmember to get the oil pan out. It was a proper mess inside as well as outside, so it got a thorough cleaning before I proceeded. (Midway through the cleaning shown below)



The gasket was fractionally small, but it did stretch to fit the corner bolt holes, and after that reassembly was, if not easy, straightforward. Bolt drain pan back on, bolt crossmember back on, lower transmission, bolt transmission back on, remove jack, replace drain plugs, add 9.5 quarts of Dex III.

Two pieces still to do. The fluid looks a little low (probably the authors of the manual were not counting on the pan being entirely removed and drained) so I'll add another half quart to a quart of fluid to bring it up to the proper level on the dipstick. Then I'll put the flywheel cover back on and the job should be done.

During the process, I discovered that the transmission mounts are absolutely shot. It seems like I should be able to replace them using the same trick - jacking the transmission up a bit to gain access, and then pulling and replacing the mounts. So, two questions:
1) Any tips on the process?
2) I found replacement mounts from two vendors, Ames and Kanter. Kanter is a little cheaper, but I haven't used them before. Are they a reputable/high quality supplier?

[Safari Larry]

It isn't uncommon for those mounts to go bad. I have no tips, replacing them straight forward.

Kanter is reputable. If there is a problem, they will stand behind it. But I had a bad experience with them. I bought a front-end kit from them to save a few bucks. One of the parts was bad and I had to return it 3 times before finally getting a good one. For details, see https://www.pontiacsafari.com/KanterProblems/. For me, a main issue was that I couldn't call them and explain my problem, I had to take photos, explain the issue, and send to them for each return of defective part. They understand Chevys, not Pontiacs.

Ames or CPR will more likely understand when you call and explain a problem. I generally prefer CPR over Ames but they don't list the rear motor mounts.

[TXSTARFIRE]

I wouldn't add more fluid until the car has been driven some distance. Most vehicles require the trans to be at operating temp when checking the fluid level. There is a difference in the level between cold and hot.

[Parkman51]

Transmission mounts are backordered, probably a few weeks before they come in. In the meantime, I'm looking at the AC system, and have two main questions:

1) Where can I find paperwork on the system? It's not listed under Accessories in the shop manuals, that I can see.
2) I have a source that can get me R-12, so my assumption would be to recharge rather than trying to convert the system to 134a. Is this accurate?

[Parkman51]

A few small projects over the past two weeks, as I do research on a/c:

First, since CPR has been out of upper door bumpers for the past two orders, and Steele costs way too much, I started learning 3d modeling and made some bumpers myself from flexible rubberized filament.



Second, for as much time as I have the hood open, the engine compartment light draws too much power and gets way too hot. So I replaced it with a nice bright LED tower - it's easily three times as bright and doesn't heat up at all.



Third, I found a small vacuum leak in the bridge line at the vacuum cylinder. Fortunately, I still had eight inches of correctly dimensioned hose left over, so I swapped in a small bridge piece and lightly clamped it.



The next thing on the list is, regrettably, more transmission work. The new fluid is a little thinner than the old was (probably since it isn't clogged up with gunk), which has revealed two additional persistent drippings out of the side cover. So a new gasket is to be ordered for that.

Today's question is: I've read that these cars are sensitive to proper adjustment of the transmission shift linkage, which comes out of the transmission side cover here. In the process of removing this cover and replacing the gasket, supposing I have to disassemble the linkage to do any of these things, what's the best way to reassemble it accurately? On the same topic, the photo below shows that some of the fluid at least is leaking out of the linkage hole - is there a separate gasket I need for that, or will the larger cover gasket solve that problem as well?

[Bill Hanlon]

From the GMC Master Parts Book, but the seals should be the same ...

I think the parts you are looking for are 17.4404 and 17.4418.

Somebody like Dave Edwards or Fatsco may be able to help.

[Onestone]

Originally Posted by Parkman51

A few small projects over the past two weeks, as I do research on a/c:

First, since CPR has been out of upper door bumpers for the past two orders, and Steele costs way too much, I started learning 3d modeling and made some bumpers myself from flexible rubberized filament.

Attachment 671565

Love it

[Parkman51]

The side cover gasket is still a much larger project than I wanted it to be, but it's not quite as bad as the bottom gasket. The side cover butts up against one of the transmission mounts (the old ones, because - thank Providence - the new ones have STILL not come in), but instead of having to take off the entire mount, I just got to remove the broken bottom half. Then out came the cover.



Absolutely caked with grime, of course. Now, I also pulled out the lever seal, and after some searching, found a replacement from Fatsco. Wonderful folks over there. They also had replacement bolts with crush washers already installed, which was great, because I couldn't find this size washer anywhere else. (For those unaware, the side cover has 13 bolts, of which the bottom 5 are under the fluid level, and so require crush washers. The other 8 bolts are not, and only have lock washers.) The seal and bolts should be here in a week or so.



When that's done, I'm going to replace the drain plug seal, and hopefully that will end the Saga of the Leaky Transmission. Then it's back to the windshield wiper hookup - which I think I've finally cracked - and the a/c.