Cooler pans for TH-400

[Gorf]

Anyone use a "cooler" pan for thier 400? I noticed them on the wall at my local parts place tonight. They are all aluminum (I think) and have big cooling fins. Unfortunately they are about 100$.

Anyone had any good luck with them? Think they are worth it?

I have been thinking of pulling my pan off, doing a filter change and throwing a shift kit in at the same time. I figure if I am going to have the pan off, I would consider one of these things.

[DOC]

hey Gorf,

nice job on the new board! IMO, the finned aluminum pan is nice for looking at, but, better bang for the buck is an aux cooler mounted in front of the AC condensor. an after market trans temp guage will let you keep an eye on things.

DOC

[tommyhawk13]

Some hold more fluid. I think it's a good idea, heat is the number one transmission killer. I want the cooler and the finned pan.

[Caddycarlo]

they don't help a hole bunch ...... the extra vol will take longer to heat up so in a drag race that could help but if you need more cooling a good cooler like b-m has will be more help ...... he is right in that heat is the thing that kills most trannys ....... the good news is that the high stall converters are what add a lot of heat and the caddy being a low rpm motor does not need the high stall that a SBC would need ........

[curtis73]

They don't do much for cooling (maybe a couple degrees) but I like them for two main reasons; most have a drain plug, and the flange seals so much better than the stamped steel.

My only issue with them is that the extra capacity makes them hang too low for my taste. I've smacked one on a speed bump before and destroyed it. At least with a steel pan, chances are you just dent it and you can drive it for a while until you fix it. If you smack that aluminum pan, you just dumped 8 quarts of ATF in Home Depot's parking lot.

I did look with great interest at a Derale pan. Its steel with tubes welded in. The tubes are exposed to the air and travel through the fluid. Seems like the best of both worlds.

[Forrest McCanless]

Finned pans are essentially useless. Fluid has so much more heat capacity than air that useful heat transfer requires a LOT of air flow over the volume of liquid to be cooled (boat "radiators" are tiny - fluid-to-fluid heat transfer is much more efficient)

Heat flow from the edges of a relatively large volume of ATF-like fluid (relative to its surface area) is essentially non-existant. The fluid thermally stratifies, and the layers act as insulators against heat flow outward. If you ever look at heat treating, it is always spelled out that the oil be "thoroughly agitated" - otherwise you don't get the cooling rate required for your hardening.

The idea of a radiator is to both thin the fluid volume section and spread the fluid out so that the same volume of fluid sees a relatively huge surface area across a relatively small volume (imagine one cubic inch cut from a radiator and compare the fluid volume to the fin area).

All that said, I had cast finned Edelbrock valve covers, trans pan, and engine pan on my high school V-8 Vega - they looked great, and the gaskets never leaked. I did loose the oil pan to a railroad crossing, though . . .

FMcC

[rivvgs]

the unit mentioned with the tubes simular to a boiler, arte markited by b and m. the external cooler mentioned in front of the radiator is not always what it appears to be, some do less than the stock heat exchanger in the radiator. there are some good coolers out there but they are not $19.95.Here is another 2 cents. the stock metering of oil during a shift in a caddie 400 is the sloppiest in all GM, imagine grama spilling her coffie during a 1-2 up shift in her new 69 deville. these sloppy shifts will eventually cause heat and deregredation of the friction material if repeated wide open upshifts are allowed to slide into gear. the feed holes and accumulator spring rates should be modified for these trans to live being hammered on a routine bassis.I have built many a turbo 475 for tool trucks. these use the same frictions with straight cut gear reduction units and ball bearing in the rear shaft at output. the frictions last twice as long, using synthetic trans fluid, also have a freind that builds turbo 350s for a evasive driving school given at local road coarse for law enforcment ect. since he began using synthetic oil, the frictions dont show wear, all kinds of hard parts still break, but frition disks are used over. the weak link in a turbo 400 when the shift becomes more agressive is the second gear sprag clutch.since around 1971 or so they have been roller type clutches, and without changing the high gear durm to a older smooth race type, that was useing in the flipper, as I call them, type sprags youhave no upgrade choice. but these can be retrofited, and a 34 element heavy duty sprag used. Band M said 300 percent stronger, I have broke stock sprags with a low compression 350 chevy and a shift Kit. just my 2 cents for what its worth Tom 8)

[rivvgs]

also, any time you are useing a converter that has a stall speed higher than your normal crusing rpm, you are going to build more heat than you can reasonably get rid of. you can run a 10 inch 3500 stall advertised convertor if you are running 3.73s-4.10s and turning 3500 at 70 mph. but if you have a set of 2.45s and a 3500 stall you will be hard pushed to run 70 in second without being in enough slip to cause heat

[fleetwood472]

Cant you fix the sloppy shifts by replacing the waved plate in the direct drum and forward drum with a flat steel? Also you say on the turbo 475 you use bearings for the out put shaft how do you do that? Can it be done on the turbo 400? I was just wondering because I am in the middle of building a turbo 400 and am looking for any useful information that I can find. Do you have any advice on things to change in the turbo 400? I already replaced all of the plastic thrust washers with bronze and have a 6 disk direct drum with a 34 element sprag. Are there any certain brands of synthetic transmission fluid that you recommend like amsoil?
Thanks - Justin

[Bugzaper]

I rebuilt mine two years ago and installed a simple shift improver kit with a adjustable vaccum modulator and installed an "Allision" brand torque convertor (type used in tow trucks). This thing just about puts you in the back seat when shifting, actually chirps the tires on 2nd to 3rd. I sometimes think I may have went a little overboard. :roll: But it's much nicer than the ole "Did it shift yet or not" feeling.

the unit mentioned with the tubes simular to a boiler, arte markited by b and m. the external cooler mentioned in front of the radiator is not always what it appears to be, some do less than the stock heat exchanger in the radiator. there are some good coolers out there but they are not $19.95.Here is another 2 cents. the stock metering of oil during a shift in a caddie 400 is the sloppiest in all GM, imagine grama spilling her coffie during a 1-2 up shift in her new 69 deville. these sloppy shifts will eventually cause heat and deregredation of the friction material if repeated wide open upshifts are allowed to slide into gear. the feed holes and accumulator spring rates should be modified for these trans to live being hammered on a routine bassis.I have built many a turbo 475 for tool trucks. these use the same frictions with straight cut gear reduction units and ball bearing in the rear shaft at output. the frictions last twice as long, using synthetic trans fluid, also have a freind that builds turbo 350s for a evasive driving school given at local road coarse for law enforcment ect. since he began using synthetic oil, the frictions dont show wear, all kinds of hard parts still break, but frition disks are used over. the weak link in a turbo 400 when the shift becomes more agressive is the second gear sprag clutch.since around 1971 or so they have been roller type clutches, and without changing the high gear durm to a older smooth race type, that was useing in the flipper, as I call them, type sprags youhave no upgrade choice. but these can be retrofited, and a 34 element heavy duty sprag used. Band M said 300 percent stronger, I have broke stock sprags with a low compression 350 chevy and a shift Kit. just my 2 cents for what its worth Tom 8)

[rivvgs]

the 475s that i have seen were used in Gruman vans, ie like a bread truck. the purpose for the caged roller bearing on the output is to support the weight of the huge drum brake on the back used for a parking brake. Have never had any problems related to bushings used on passenger cars and there is much less mass to get moving. I have at customers request installed the straight cut reduction units in tow vehicles. But I have only seen one normal passeger unit fail. hey those 6 clutch smooth race clutch drums are getting tough to find, most I have seen were in caddie originally. Just put one together for buddies 454 toter home used my last 6 clutch smooth race drum, Trans go swears you will never pull through a 5 clutch unit with thier kit. Amsoil is fine stuff, just a little hard to find on the road,but you shouldnt need any on the road. I use a aliison convertor in all 400s I am building for heavy vehicles buddies toter weighs 24,000, a bit more than even a caddie. he sure wishes it had more brakes. Lots of weight for a 1 ton chassis to stop even with three axle trailer brakes. another little trick I have used is to use the roller bearing thrust from between direct and forward in a turbo 350 in place of the thrust washer in the rear of a 400, frees them up enoght you can feel it rotateing it by hand. oh well good luck riv

[rivvgs]

removeing the wave plate from forward clutch will just make a harsh neutral to drive, after the clutch is applyed, it stays applied in all forward gears not effecting shift at all. direct will firm up high gear some but with out installing a orface in the rear band feed, it will make reverse apply harsh too.I usually drill feed ports to 1/8 inch in seperator plate, block oil to 2-3 accumulator, a known leak ,use borg warner clutches,remove the wave plates, and this is ok for most applications, for hotter unit you need to replace 1-2 spool and block hole in valve body or its gona come outa low when it wants to, use a stiffer presure relief spring in pump, and use the whole surface of the high gear apply piston, :P 400s have so many things you can do, but bassicly they are strong with ony mild build up besides the sprag

[fleetwood472]

Have you ever had any problems with the case bushing walking out of the bore? Also I was wondering what you thought of these clutches that came in my rebuild kit from transmission exchange I will attach a picture let me know what you think of them should they be ok or should I get different ones? Also is Alto a good brand for clutches? How much did it cost you for the bearing for the output shaft and where did you find the shims is there anything special you have to do to get it to fit? So with taking out the waved plate in the direct drum I will have harsh shifts and harsh reverse engagement? I am going to be using this in my 78 Fleetwood with switch pitch and a mildly modified 1973 500. I want to use the car for towing stuff like boats and atv trailers that hold 4 atvs. Will it be ok using a waved plate and these clutches? Thanks - Justin

[rivvgs]

I didnt mean to tell you not to remove the wave plate, I very seldom put them in direct, but there is nothing to be gained by removeing it from forward clutch. to achieve reverse in a 400 you apply direct clutch and rear band, the only other time rear band is engaged is in manuel Low for engine braking.you can let the direct clutch engage harsh as it wants with the wave plate removed and you will never feel it if tou put a orface in the rear band feed to apply it gently, it take both to engage, it makes no difference where you have the cushion, while in drive and the firmness desired on a 2-3 shift the missing wave plate will achieve the desired result with no harsh reverse engagement. I think you will find that either Borg warner or raysbestos made the clutches in your alto kit, I have used both, but I personaly prefer borg warner. I hope that answers your question. I am moving after 30 years, bet I have thrown enough stuff away to build a dozen 400s still have a switch pitch too. good luck on your project

[fleetwood472]

Where at do you put the orifice? Also since it slows down the apply of the rear bad will it slow it down when I put it into manual low to do a manual downshift? Also what do you think about the basic transgo shift kit? I saw it came with stiffer direct drum springs have you ever used them or are the stock ones fine? Thanks - Justin

[rivvgs]

yes I like the transgo kit just fine, but, fairly pricy and I usually use the springs , but if you have it all together I wouldnt take it apart just for that. I prefer the supierior brand kits for a 400 myself. look under the cover on the servo for rear band, you can see the feed, there is a round hole in the case body you can install a plug with like a 1/16 hole drilled in it, and yes it will slow manual low engagement but who cares, it needs not to be harsh either

[dave_brode]

rivvgs,

I understand why the wave in the forward doesn't hurt plate wear like it might in the direct. However, I've always pitched the waves, and all the builds that I've done N-D and to R engagement was only slightly harsher.
On the other hand, I do know a fellow that built one 400 that really hammered upon D or R engagement. I was always puzzled by that one.

Do you use a different pack clearance when using the wave vs no wave in the forward? What clearances do you see as best for the clutch packs?


> direct will firm up high gear some but with out installing a orface in the rear band feed, it will make reverse apply harsh too.

Where is this restrictor orifice installed? What size?

> I usually drill feed ports to 1/8 inch in seperator plate, block oil to 2-3 accumulator, a known leak

Block oil to 2-3 accumulator in the valve body? Anything else need done when doing that?

> use a stiffer presure relief spring in pump,

Where to buy spring? What installed hiegth? How much line pressure is good for fully automatic street/strip?

> and use the whole surface of the high gear apply piston,

By removing center seals, and blocking port on center support?
[memory is fuzzy on that]


Does Younger have a tech guide, or do you know of other printed matter explaining the mods that you describe?

Thanks much in advance.

[fleetwood472]

Have any of you guys machined the apply pistons for either of these clutches? If so how much did you take off? I was thinking of doing it for the forward drum but wasnt sure how much to take off I want to use 6 clutches in the forward. Also I hear that up to 7 clutches can be added to the direct drum is this true? I think I will probably just stick to 6 but I was just wondering.