transmission cooler?

[SubaruNation]

Has anyone made one of these? Where could I attach a cooling line if
So? Any ideas? Supposed to extend tranny life.

Thanks

[vrg3]

It'd be hard to do with a manual transmission because the fluid isn't circulating; it's just kind of splashing around everything in there. I suppose you could design some kind of system with a pump and radiator -- perhaps draw fluid from where the drain plug goes and return it to the dipstick hole, with some kind of intermediate chamber to allow froth to settle -- but it doesn't seem worth it to me.

[SLODRIVE]

If you're talking about one for your TW, you can get a complete kit for under $50 at any decent parts store, and it should include everything you need. Get the biggest one you can fit/afford and hook it up per the instructions in the box.

If you want one for your SS...+1 to vrg3's post. Not worth it.

[vrg3]

Oh. Right, my bad. I didn't read all the way through your signature.

Yeah, like SLODRIVE said, tranny cooler kits for autos are plentiful and cheap. It should be fairly easy to hook up; you splice it into the transmission cooler lines that are already on the left end of the radiator. I can't remember for sure, but either 5/16" or 3/8" hose will fit. Be sure to use hose made for this purpose. ATF will eat through regular hose. The kit should come with it and with adapters.

[SubaruNation]

aw drat. i wanted to put one in the 91, but it would be a good idea to put one in the TW after i repair/swap out the existing dead tranny.
it doesnt exactly shift out of 2nd gear . no 3rd and 4th gear.

hopefully a flush will help. thats neat that its just a kit, just installs no big deal.

thanks guys

[fishbone79]

I have seen MT's with transmission coolers (none subaru though). They basic idea is a small recirc pump in the transmission sump, and a return jet line that usually goes in the neutral safely switch hole.

Their effectiveness is a little dubious, but these are on heavy trucks. Their real value to truck transmissions is the addition of a filter, but the systems usually have a cooler as well. As far as installation, they are a breeze... On the ones I've seen the pump is small and is inserted through the drain plug in the sump.

I've read this book cover-to-cover (among many others), its a good read if your interested in an overview of MT transmissions with some hard facts:
http://books.google.com/books?id=TsBde1 ... frontcover

It's slightly dated, but still relevant.


Here's the bit on MT cooling:
long book link

Contrary to what other's have suggested, cooling is important in MT's in any performance application. However, it's generally more difficult to implement because the transmission is not usually pumping the fluid for another reason. Allot of the audi team rally guys used transmission coolant systems in the early days of AWD proper. The most notable is the pikes peak S1.

[SLODRIVE]

Contrary to what other's have suggested, cooling is important in MT's in any performance application. However, it's generally more difficult to implement because the transmission is not usually pumping the fluid for another reason. Allot of the audi team rally guys used transmission coolant systems in the early days of AWD proper. The most notable is the pikes peak S1.

I think your post is a little misleading. Nobody said cooling isn't important, but the thing is, there isn't necessarily a need for additional cooling on a manual tranny, even in performance (and most racing...yes) applications. There's nothing wrong with an external M/T cooler in and of itself, but unless you're going endurance, off-road, Nextel Cup, etc. racing it's mostly a waste of money. It also isn't normally used when not needed because of the extra space and weight, not to mention the addition of more places to potentially leak transmission fluid. I'm not saying there's no cars that need them or have them for good reason...there's just plenty of reasons NOT to use them on cars that don't need them.

Manual transmissions don't generate nearly the amount of heat as an automatic transmission or an engine, and you'll have a really hard time getting the fluid hot enough for long enough to cause any kind of lubricant breakdown, assuming the transmission has good fluid in it to begin with. If you're concerned about extending your 5-speed's life, I think you'll be better off changing the fluid once in a while.

JMHO

[fishbone79]

Contrary to what other's have suggested, cooling is important in MT's in any performance application. However, it's generally more difficult to implement because the transmission is not usually pumping the fluid for another reason. Allot of the audi team rally guys used transmission coolant systems in the early days of AWD proper. The most notable is the pikes peak S1.

I think your post is a little misleading. Nobody said cooling isn't important, but the thing is, there isn't necessarily a need for additional cooling on a manual tranny, even in performance (and most racing...yes) applications. There's nothing wrong with an external M/T cooler in and of itself, but unless you're going endurance, off-road, Nextel Cup, etc. racing it's mostly a waste of money. It also isn't normally used when not needed because of the extra space and weight, not to mention the addition of more places to potentially leak transmission fluid. I'm not saying there's no cars that need them or have them for good reason...there's just plenty of reasons NOT to use them on cars that don't need them.

Manual transmissions don't generate nearly the amount of heat as an automatic transmission or an engine, and you'll have a really hard time getting the fluid hot enough for long enough to cause any kind of lubricant breakdown, assuming the transmission has good fluid in it to begin with. If you're concerned about extending your 5-speed's life, I think you'll be better off changing the fluid once in a while.

JMHO

I absolutely agree. I should clarify, I did not mean contrary to what other's have suggested _here_, but contrary to the traditional point of view as it has been discussed, ad nauseam (on this forum and elsewhere). Sorry about that.

I also agree that it is a colossal waste of time on a subie tranny (and probably most anything off the track, for that matter). Audi's initial AWD transmissions (and some of their newer ones, I'm told) used an all-gear, hard-connect center diff that generated substantial amounts of heat. It was to the breakdown point of synthetic, and adding a cooler greatly increased the tranny's lifespan. However, subaru's viscous diff is a superior design, particularly at dissipating (or simply not creating) excessive heat, IMHO.