FogRunner

What part of the country (climate) do you live in? Reason I ask is I wanted to know why you installed a temp bypass valve.

I thought about putting in a valve but after talking to several transmission shops and mechanics I decided that as long as it doesn't run below 100-110F that it wasn't too cold.

I just don't like the thought of my transmission running 170-180F when there is no reason for it to be that high. With a engine I know you want higher temps for water evaporation and better combustion.

But since a transmission doesn't have any combustion or have the moisture load due to blow-by in a combustion engine and since ATF doesn't need the higher temps to function properly like motor oil does there isn't a reason to keep it at such high temps.

Don't get me wrong there is a place for the temp valves in cold climates, but I see allot of people put them because they under under the impression their transmission "needs" to be >175F all the time to function properly.

98srx6

I live in Chicago but frequently travel to Upper Michigan where normal winter temperatures can drop as low as -25*f. I figured that the bypass would be a cheap way to avoid the increased flow restriction that the fluid will inevitably experience when traveling through the cooler with ambient temps from -25*f to +30*f. Also, warmer fluid permits the transmission to operate more efficiently allowing for a slight increase in fuel economy (and IMO a noticeable improvement in power).

Basically the reason I bought it is that I am not a transmission expert and I decided that the bypass would be a cheap, easy way to decrease the risk of damaging my transmission with very little added risk due to the bypass valve. This is based on my experience with hydraulic systems and my very limited knowledge of auto transmissions/torque converters.

Ron Helmuth

bump for a great thread-the older the 3rd gens get the more people seem to be experiencing the milkshake.

Be pro active folks and save your auto trannys. Replace the radiator or add an external tranny cooler your choice...

gpcollen1

That is pretty much where mine failed. Once I took it out the fitting came right off in my hand.

SkidPalace

Now if someone could crack open a Koyo radiator for a side by side comparison, that would be sweet.

CodyX36

This should be stickied.

Thanks for those pictures, I'll definitely have to get a new radiator ordered here soon, probably Monday I'll get one through work and get it installed soon after.

legokcen

Great info man. Thanks! I appreciate the insight and the knowledge. You didn't have to, so again, thanks.

4runnerdave

Just came across this thread, cracked my rad across the whole bottom yesterday. nice to see whats happening inside. Just ordered a Koyo rad, and a full oe/oem timing blet/waterpump kit. hoping a refresh with new fuilds will save my baby...just prayin I didnt do internal damage. 95+ degree heat in stop and go traffic towin a 2,000lb trailer...not the best idea in hindsight. totally looking into a tranny cooler too. damn thing only has a 104k!

Jarhead2147

Nice job with the pics. I have a '92 with a little different setup but I may still put in a seperate trans cooler. thanks

mt_goat

Thanks for bumping this, I can't believe I never saw it.

wifes4now

thanks for taking the time to make this post
this moves the trans cooler back up my list of stuff to do

guitarplayer360

+1. Still need to get the rad replaced in my 98'... although It has 173k on it, and hasnt had one problem yet...knock on wood.

Rock Slide

iTrader: (1)

For preventative maint, I just replaced the stock rad in my wife's '00 4Runner w/ an OEM model I got at a discounted price ($200 out the door) thru my local dealer. Went with new upper & lower hoses too. Glad I replaced it when I did...the hoses looked like crap inside, the rad fluid itself was almost yellow it was so dirty and the rad itself had developed a small crack on the left side I hadn't seen until now. I'm all set now though. Just glad I did it when I did.

I may crack open the original rad this weekend and see what the cooler looks like. Just need to get around and replace the stock rad on my '02 as a precaution as well...

Garage Guy

+1 on that. If the Koyo has just the same problem waiting to happen, not much reason to swap one in IMO.