Topic: Boat/Auto trans questions...

Ok, so I'm building a boat (LS400). and Its got a dreaded auto trans with 250k miles on it. What I'm wondering is, do I need a trans cooler, or is the stock tube in the radiator cooler good enough? I have zero auto trans experience and I have a old Corolla oil cooler lying around I can use, but not sure if I need it?

Thanks..

"Don't mess with Lexas!" LS400. We survived another one! See website link for build details.
Maker of the "unofficial Lemons fish!" - If you ask nice, I'll likely give you one at the track.

Re: Boat/Auto trans questions...

yes.  you probably can't cool an auto trans enough in a Lemons race.

mike - Schumacher Taxi Service
12+-time loser
"Winner" - We Got Screwed, NJMP '11

Re: Boat/Auto trans questions...

Buzz Killington wrote:

yes.  you probably can't cool an auto trans enough in a Lemons race.

Thanks for the tip. best thing is, its a 5 minute, zero cost mod since I have an old cooler lying around.

"Don't mess with Lexas!" LS400. We survived another one! See website link for build details.
Maker of the "unofficial Lemons fish!" - If you ask nice, I'll likely give you one at the track.

Re: Boat/Auto trans questions...

You can also try and us the A/C condenser that's already on the Lexus.

Troy

#35 LRE
1973 Datsun 240Z

Re: Boat/Auto trans questions...

I've seen racers use small-car radiators as trans coolers, too. An extra electric cooling fan (easily found at the junkyard) will help. It is true that you can't over-cool an automatic transmission in a big car.

Re: Boat/Auto trans questions...

I once raced an auto Chrysler Newport (don't ask) and used a Dodge Dart rad as an oil cooler by sealing the rad hose outlets, filling with water and using the stock line connections....very effective. Best tactic is to flush the trans completely (go to a trans shop for this...get them to use the Big Machine) then use synthetic trans fluid. Change the filter or gut it for a simple screen since a clogged filter isn't going to save the trans anyway. If you can fab a deeper pan, do so....many import slushboxes use a minimal fluid volume...if you can, rig a small tank or maybe use v. fat lines to the cooler, the extra volume will help. Check that the pickup stands off the pan bottom and is firmly attached...I've seen some slip down and suck air or choke off the pickup...if it's electronically controlled, remember overdrive and lockup converters....you don't want either cycling on and off, which it will if there's a decent straight....disable or lock out the OD at the selector lever...converter clutch can be as simple as cutting wires. GM mechanics used to do this on 700R4's to address customer complaints about "surge" as the converter locked. Seperating trns and engine cooling can also prevent a mystery engine overheating issue....jeez, I oughtta start a team....

Jim "Endo" Anderton
30 years of racing and still not Brambilla.....

Re: Boat/Auto trans questions...

Wow.. I hadn't considered using a whole 'nuther radiator.. Is it possible to OVER cool it? I guess the AC condensor would be the easiest since the twin electric fans normally mount to that anyway.

"Don't mess with Lexas!" LS400. We survived another one! See website link for build details.
Maker of the "unofficial Lemons fish!" - If you ask nice, I'll likely give you one at the track.

Re: Boat/Auto trans questions...

jimeditorial wrote:

I once raced an auto Chrysler Newport (don't ask) and used a Dodge Dart rad as an oil cooler by sealing the rad hose outlets, filling with water and using the stock line connections....very effective. Best tactic is to flush the trans completely (go to a trans shop for this...get them to use the Big Machine) then use synthetic trans fluid. Change the filter or gut it for a simple screen since a clogged filter isn't going to save the trans anyway. If you can fab a deeper pan, do so....many import slushboxes use a minimal fluid volume...if you can, rig a small tank or maybe use v. fat lines to the cooler, the extra volume will help. Check that the pickup stands off the pan bottom and is firmly attached...I've seen some slip down and suck air or choke off the pickup...if it's electronically controlled, remember overdrive and lockup converters....you don't want either cycling on and off, which it will if there's a decent straight....disable or lock out the OD at the selector lever...converter clutch can be as simple as cutting wires. GM mechanics used to do this on 700R4's to address customer complaints about "surge" as the converter locked. Seperating trns and engine cooling can also prevent a mystery engine overheating issue....jeez, I oughtta start a team....

Good tips.. there's a button to lock out OD, and it stays locked out on restart, so good there. I'll hook up a big cooler and have the pro's flush it... sure would be easier to pop a supra manual trans on there!

"Don't mess with Lexas!" LS400. We survived another one! See website link for build details.
Maker of the "unofficial Lemons fish!" - If you ask nice, I'll likely give you one at the track.