[vertigto]

I'm rebuilding the TH400 in my '70 GT0 and since the pan is a little dented/scratched up and I'm doing a frame off resto, thought this would be the best time to replace.

The supposed OEM style replacements don't look exactly like my original, otherwise I would probably go that route. Also...don't see a reason for a deeper pan for my stock-ish resto.

So...what are the best replacement options? Cast/finned aluminum vs. steel? Longshot....anyone have an original in mint condition?

Thoughts/recommendations??

[David Jones]

When my car had its T400, I ran a lightly finned stockish depth cast aluminum pan. It never leaked, you didn’t worry about it bending and the rubber gasket was reusable.

[Half-Inch Stud]

Steel embossed with Turbo Hydramatic division

[GoGoat]

FWIW I couldn't get the rubber gasket to seal. Went to a cork gasket and sealed . Also I used 4 studs I made to hold gasket till I got pan on and then replaced studs with bolts. Hope this helps. Good luck

[Schurkey]

"Most" trans pan gaskets have a few "small" holes spaced around the gasket that will hold the bolt (and therefore the gasket) in place while you get the pan, gasket, and those bolts lined-up with the bolt holes they go into.

Some gaskets have all the holes small enough to do this.

[vertigto]

Can't seem to find any cast aluminum in the stock depth. Quite a few finned styles in both aluminum and steel??

Guessing the benefit of aluminum is weight, but steel stronger/less prone to warping? Either seal better? Looks like cork over rubber gasket, unless I find a cast aluminum in stock depth?

Not looking to spend $200+ on a pan or extra depth.

[Dragncar]

Cast aluminum, stock depth, cheap.
https://www.summitracing.com/parts/sum-g3892b

Currently I run one of these. Its deeper but not really as the filter is right above the cooling tubes so no need to drop the filter down.
https://www.summitracing.com/parts/der-14201

Going to a big fat cast deep aluminum pan that will need the filter dropped this next race season.

[Schurkey]

Originally Posted by vertigto

I'm rebuilding the TH400 in my '70 GT0 and since the pan is a little dented/scratched up and I'm doing a frame off resto,

This is a restoration, right? Not a modified car?

You sure do not want an aluminum pan. Go to any Trans shop in your area, buy an undamaged core automobile TH400 pan for a trans newer than '67 model year (68-newer), have it grit blasted--sand, bead, walnut shells, whatever--and bolt it on. Maybe you want to paint it, but I'm thinking they were plain steel originally.

Done.

[OG68]

I understand you're not looking for a deep pan, but I used the factory deep steel pan with filter extension from an 80s 3/4 ton GMC pickup on my El Camino. No leaks and best of all it was $10 from my local Pick and Pull

[TCSGTO]

Originally Posted by OG68

I understand you're not looking for a deep pan, but I used the factory deep steel pan with filter extension from an 80s 3/4 ton GMC pickup on my El Camino. No leaks and best of all it was $10 from my local Pick and Pull

I used the same one. GM quit making them but if you look around they’re out there.

[FrankieT/A]

Originally Posted by Dragncar

Currently I run one of these. Its deeper but not really as the filter is right above the cooling tubes so no need to drop the filter down.
https://www.summitracing.com/parts/der-14201

I have have been using one of these for the last 40 years or so...

[Half-Inch Stud]

Aluminum pan is very heavy compared to steel. Maybe heavier than Truck Steel deep pan.


I use to use the steel truck pans, but went back to legacy steel TH400 pan. No real reason.

Sealing the TH400 pan appears to be a science, depending on the Pan fidelity, and the CORK gasket.
i toss the rubber pan gaskets in the creek.

A Moulded Silicone/steel gasket is long over due.

[Gator67]

I went through this with my wife's Firebird. I could get the factory pan sealed up for a while with a cork gasket, but eventually it would start seeping and then would drip. If I tightened the pan at all, it would only get worse, and then I'd have to take the pan off and straighten out the edges and bolt holes, and start again. Not a big job, but messy and not something I liked doing every year. Finally broke down and installed an aluminum pan (a deep one from TCI) and no more seeping or leaks...used the cheap fiber gasket (Farpak IIRC) that came in the box with no sealer. If your car is a #1 showpiece, obviously this won't work.

[Kenth]

Be prepaired to modify the cable bracket using an aluminium TH400 pan.
Most aftermarket chrome pans have higher bulges than GM pans between bolt holes cutting the gasket if bolts are torqued too much.
Thick cork gasket glued to pan and no more than 12 lb/ft recommended will work with the chrome pans.

[ANDYA]

It sounds like your restoring your car to appear all original. You said in your first post that your original pan is only a little dented. It may be worth it to straighten out your original as long as it is not smashed. You can attempt it yourself or a good body guy can fix it at a reasonable cost. You should be able to get it pretty close maybe only needing a thin coat of filler before painting.

[vertigto]

So...the frame off resto is not exactly to factory specs (upgraded suspension, steering box, DUI ignition, 18s, RARE logs, Cold case, etc.), but the engine/drivetrain is original/numbers matching. Basicallly upgrading the driveability to more modern specs and a slightly lowered stance.

The pan looks like this...



Unfortunately I didn't notice it before sending out for rebuild and don't really have the luxury of time to send to a body shop. Since I'm going through the expense of a frame off and everything else will be/look essentially new, it would be a shame to leave as is. I'll check with the shop and see if they have any spares in nice condition, but not counting on it.

I suppose the easiest thing to do would be to order something like this...



https://www.jegs.com/i/Mr-Gasket/720...6L+%2F+400+%29

... but would probably prefer something like this, with a cork gasket...



https://www.holley.com/products/driv...parts/9796PMRG

Not a big fan of polished chrome. Both are stock depth. Looks like the Summit model posted is quite a bit deeper then stock??

[Kenth]

https://www.holley.com/products/driv...parts/9796PMRG

This will NOT work with the original cable bracket.
Fine for column shift cars though.

[vertigto]

Originally Posted by Kenth

https://www.holley.com/products/driv...parts/9796PMRG

This will NOT work with the original cable bracket.
Fine for column shift cars though.

Good to know...thank you.

[Gator67]

All I had to do to the cable bracket was grind a little off the inside edge so it would sit flat. Having a drain plug will also be nice the next time I have to change the fluid. Cast aluminum doesn’t stand out, even more true if I would have gone factory depth.

[vertigto]

Anyone have a nice OEM pan that they would be willing to sell?