trans cooler question??

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

Joined
Oct 23, 2012
Threads
9
Messages
58
Location
on a rock
I just found that I have a bad fitting on one of the trans cooler lines to the radiator. Here's my question is the stock cooler enough to keep the trans cool if I bypass the radiator heat exchanger? I also was thinking about upgrading the stock cooler to a bigger plate style cooler. Would that be a good idea or too over kill. I'm not gonna tow with the cruiser just mostly slow trails.
Thanks in advance
 
in other words, you'll be fine. Mine was set up this way when i got it. Takes only a mile or two before she is warm enough to shift into OD or if you get above 55 or so, it will do it cold (or get warm enough anyways)
 
in other words, you'll be fine. Mine was set up this way when i got it. Takes only a mile or two before she is warm enough to shift into OD or if you get above 55 or so, it will do it cold (or get warm enough anyways)

thanks thats what i wanted to hear i gotta drive 3 miles before i hit a high way anyway
 
thanks thats what i wanted to hear

It may be what you wanted to hear, but it's still a bad idea. Cold fluid causes a *lot* of wear in the tranny. All that extra time waiting for O/D = time that you're putting wear on your transmission.
 
After watching my scangauge I noticed that it won't allow it to shift into overdrive until the computer see that the coolant temp is 130 degrees.
 
After watching my scangauge I noticed that it won't allow it to shift into overdrive until the computer see that the coolant temp is 130 degrees.

^^This is spot on IIRC [strike]127°[/strike] per FSM is when OD is good to go

Correction - There is no O/D up–shift or lock–up when the coolant temperature is below 55°C (131°F).
 
Last edited:
It may be what you wanted to hear, but it's still a bad idea. Cold fluid causes a *lot* of wear in the tranny. All that extra time waiting for O/D = time that you're putting wear on your transmission.

Not so sure about that. The line runs through the bottom of the radiator. The radiator doesn't get warm water until the thermostat opens. A 185F thermostat actually starts opening a little sooner, but still. Going by that, the engine will be warm before the line even sees warm coolant, then it still has to heat the rest of the trans fluid up...
 
Not so sure about that. The line runs through the bottom of the radiator. The radiator doesn't get warm water until the thermostat opens. A 185F thermostat actually starts opening a little sooner, but still. Going by that, the engine will be warm before the line even sees warm coolant, then it still has to heat the rest of the trans fluid up...

Not exactly...The coolant bypass hose starts dumping in the same temp water as the engine water temp. By the time the thermostat starts to opens the radiator is almost at 100°. On my 80 when the engine water temp reads 130° trans temp is at 80°. Almost identical numbers on our 100 series with same trans and a little larger trans cooler.
 
Maybe I'm crazy, but why wouldn't you replace the failed part with a new one?
It's your transmission. I'm no mechanic, but I believe that's a fairly important part of the truck.

because it probably means getting a new radiator... Not cheap.

Not exactly...The coolant bypass hose starts dumping in the same temp water as the engine water temp. By the time the thermostat starts to opens the radiator is almost at 100°. On my 80 when the engine water temp reads 130° trans temp is at 80°. Almost identical numbers on our 100 series with same trans and a little larger trans cooler.

right, but that is probably due to you driving it and the transmission creating the heat. That's my point. A warmer is there to make the transmission shift that little bit smoother a little bit faster. How many transmissions failures here can be attributed to too cold of fluid?
 
right, but that is probably due to you driving it and the transmission creating the heat. That's my point. A warmer is there to make the transmission shift that little bit smoother a little bit faster. How many transmissions failures here can be attributed to too cold of fluid?

Ah - No driving just sitting in park is where my data came from.

Correction - There is no O/D up–shift or lock–up when the coolant temperature is below 55°C (131°F).

Interesting that when towing Lock-up and OD are the fastest heat generators but Toyota will not let you use either until the trans sees temp.
 
Last edited:
The main reason I wanted to bypass the radiator is I didn't want to wait for the part to come in dealer didn't have it.
So I have it bypassed now it runs fine even when cold it shifts to 4th once you get a little over 50.
I also have a 99 4runner I bypassed the stock heat exchanger to a plate cooler almost 10 years ago its still running the original trans at 185000 miles.
What I was worried about bypassing the lc radiator was the trans heating up and the stock cooler being too small.
thanks
 
Yea I did some research on the matter and started the thread that was linked above, but I'm no expert. I think the truth is nobody really knows how much wear you will do over time without the radiator oil cooler. These trucks aren't rocket science, and I don't buy into the voodoo that if everything isn't perfect something will blow up. I'm definitely not denying there's logical proof or science behind what the people above are saying, and I can't logically make a defense that having no rad oil cooler is better than having it the way mr.T designed, but if under the circumstances (like cost) its better to delete the unit I don't think it will cause a catastrophic failure. Honestly, I think if you replaced the tranny fluid with synthetic you'd be getting the best of both worlds. Correct me if I'm wrong, but the new synthetic dexron stuff has greater protection cold than regular dexII warmed up a bit (talking about the old stuff these trucks were designed to use back in the 90's).

Anyway, just throwing it out there that if you own a beater like me, having new parts and making every little thing work as designed isn't always the top priority. I buy OEM parts when necessary and do extensive maintenance just like most on here, but sometimes the juice isn't worth the squeeze for me. BTW, I definitely won't be opposed to coming back here if/when my tranny blows and eating some crow. I guess we shall see what happens!
 
My cruiser is a beach/fishing truck its just a toy something to keep me busy lol
 
Do the rad with the heat exchanger, unless you feel it's cheaper and faster to replace the transmission if/when it dies
 

Users who are viewing this thread

Back
Top Bottom