Upgraded trans cooler

Is that 154 the pan temperature? I've never been able to get the torque converter temperature reading to work. I'm not sure about a thermostat.

Is this the Hayden your ordered?

$52 Hayden 679 Universal 11” Rapid-Cool Add-On Transmission Cooler to Enhance Cooling (not for direct replacement of the factory unit)

https://www.amazon.com/dp/B000C3BBKS/ref=cm_sw_r_cp_apa_i_07FkFbAQGKWN0

 

That is the one. I believe it is the pan temp as that is the only option it allows me to select to display. Out of all the readings, the trans temp one can be a little picky. Sometimes I have to restart the app to get it to read.

 

140 is honestly a bit too cool as it is. Ideal trans temp is 180 just like an engine. That being said 140 probably won’t hurt anything but I wouldn’t want it getting much cooler than that

 

Kind of what I was wondering/thinking. That’s why I was thinking the in-line thermostat might be a good investment.

 

T stat with a 160 degree will work fine

 

Is that at the pan or at the torque converter though? I thought it was stated that the pan will always be 20-30 degrees cooler than the internal temp but I might be wrong.

 

Seems like a lot of trouble to go through to re-engineer a system that hasn't failed. Has anyone had persistent overheating issues with their Tundra transmission? And lack of cooling was the issue? I've done some pretty heavy towing 7000+ in some steep hilly areas and not seen the needle move on mine. And the fluid needs to be warm to work properly. It's not gonna burn the fluid in the 175-200 range. Maintaining the transmission fluid level, using the proper fluid and changing at appropriate intervals per the Toyota service manual should be sufficient. Old fluid does not cool or lubricate as good as fresh fluid. I like to mod things and improve things, but I would hate to contribute to the premature failure of a part or system trying to solve a problem that doesn't exist.

 

Converter temp will always go up until it hits lockup. As long as your under 200 you fine in my eyes for torque converter temp.

 

Only reason I’m going to a massive aftermarket cooler is to remove the factory in radiator cooler and a potential coolant mixing with trans fluid issue. It’s not super common but it does happen with these trucks

 

Well I did some research and I found a bit of information. The general consensus is that you cannot over cool transmission fluid, especially in vehicles that have an additional cooler inside the radiator (like us). The cooler inside the radiator is dual purpose. It heats the fluid during colder temps and cools the fluid during warmer temps (along with the external cooler). I also called two transmission shops and they confirmed the same findings. One guy told me "Find the biggest cooler you can fit and run it." Now I would look at that within reason because I wouldn't put one large enough to block the AC condensor or radiator.

Not to say that I believe this 100% but 160* or below is a temp I am comfortable with personally. I have slowly been exchanging the current fluid with Valvoline Maxlife Synthetic each oil change which should help the life of the transmission over all as well as run better at the cooler temps.

Now, with all that being said, is this mod necessary? Absolutely not. Obviously many people have gone quite a few miles on there OEM setup with normal maintenance, or no maintenance in some cases and they still live. I like to mod my truck and this seemed like a fun inexpensive project that didn't take a whole lot of time. So far, I have only been driving it to and from work and the temps seem to stay right at 140* sometimes 150*. It's probably in my head but it seems to shift smoother between 2-3 and 3-4.

Source: Etrailer

Source: Advanced Transmission

Source:Hayden

Source:AAMCO

Source:Transmission Repair Guy

 

Seems like conflicting info. Close to 175 is best, but its OK to cool the shit out of it! I've seen a friend's vehicle blow a transmission line from overheating. I wouldn't want that fate for sure. Are the failures of Tundra transmissions caused by overheating? I've heard of numerous accounts of transmission failures in these trucks. I've not babied mine from a workload standpoint and I'm at 254k miles with only a slight 1-2 shift shudder occasionally. And mine is likely a first run on the assembly line with a Sept. 1999 build date. So weak planetary gear in these? Replaced the filter and pan gasket once around 100k miles when it was new to me. Have changed the 4 qts or so in the pan a few times since then. May start changing the fluid at oil change intervals, which is annually at this point.

 

I'm sure some are. We have 1 member here that converted his to a manual after his automatic transmission failed. When I asked him about it, he said he thought it failed because he overheated it during a trip to Moab.

I thought the planetary gear issue was only with the 02's but Google results seem to show it was from 00-02 with the upgraded planetary gear most likely in 03.

Going back to the bigger trans cooler I can see the arguments both for and against but I personally doubt running this Hayden unit will do any harm. My cooler has a bunch of bent fins from 18 years of rock strikes so I may eventually upgrade.

 

If i ever haul or tow ill switch the o/d button, but jesus christ just driving around town at 55 mph puts me at 2900 rpms already with o/d off unloaded, so if i do 65 ill prob be at 3200. Noooo thanks. It just seems a little excessive for your revs to be that high

 

Ya I can see both sides. The one site I quoted said +/- 25* from 175*. I would say 90% of failures in any auto transmission is due to heat. Whether that be from driving, over loaded, low fluid, bad fluid, etc; it all generates heat. As easy and cheap as it is, I have made it part of the oil change routine to exchange the fluid. We don't realize how good we have it having an easy access drain plug.

Well I took it a step further because I am so OCD; I contacted every shop local transmission shop near me and they all gave me the same response. I told them I installed a cooler rated for 30K GVRW vehicle and one of them literally laughed and thought it was awesome. They all said anything between 125*-175* is the perfect temp. I got one guy that seemed pretty familiar with Toyota and Japanese vehicle setups that confirmed what I originally thought. Being that it has two coolers, the one inside the radiator will heat the fluid if it gets too cold. 175* is the normal temp range but that is almost maxing out the fluid, by lowering it, you are extending the fluid life, preventing varnish on metal surfaces, preventing seals from hardening and preserving the life the bands/clutches. All of them said it won't cause any issues, even in the winter time. I did keep my older cooler just in case but I am not as worried about the temps anymore.

 

You went pretty deep with the research and it was a pleasure to read all of it, bravo!

For me personally I jumped up in size because a: I live on mainland Mexico 1/2 the year and it's regularly 95+ with humidity. B: I have a 5000lb boat that I have to tow up 2 mountains to get to the marina. It's a win in my eyes because as you said it is only extending the life of the fluid by keeping it cooler. No reinventing the wheel here just a solid mod for peace of mind. Not only that my old unit had consistent readings of 180 to 190 like yourself...that's too close to the edge for me. Thanks for taking the time to do all the footwork on research @SouthPaw

 

Some key takeaways for me from all this back and forth on these coolers:

1) Keep OEM Transmission Cooler.

2) Install a secondary cooler with an 180° by-pass thermostat so when temps rise above that 180° the secondary cooler activates inline with the OEM Cooler. This eliminates the ‘too cool for school’ fluid.

3) I’ll get a secondary B&M Cooler that will be so big I’ll need new front coils.

With all the above being said, this transmission is 18years old and not sure how much protection/life an additional cooler will add to her. Shes grunted out plenty of tow/haul over the years and been a good gurl. I’d say its not necessary to do one based on the performance and longevity over the OEM Cooler over the years, but it won’t hurt adding a secondary pinned at 180°.

‘Cool’ factoid: The 4.7L engine has an ‘oil cooler’. It is located at the oil filter. Radiator Water flows around the cooler ‘cooling’ the oil passing through to the oil filter. A large oil filter acts as a ‘cooler’, as well.

 

Further research indicates some of these trans/rad coolers have built in bypasses. In other words, they have a built in ‘thermostat’ that when the fluid is cold it restricts flow to the cooling fins and bypasses the cooling process. The cold fluid is sent back to warm up. Once warm the capillaries open and allow cooling.

Technically, which is a better option to control fluid flow for someone doing a secondary trans cooler? The inline thermostat or the built in bypass radiator system?

 

More or less. The OEM will obviously suffice but if your old needs replaced from damage or boredom (like me), do the swap . I won't be using a by-pass tstat though. (but I am not throwing away my old one yet lol).

 

My objective is to keep the OEM. My question is in regards to the secondary cooler. What is best technique for keeping temps at 180°?

1) Use a secondary cooler with built in bypass?

2) Use a secondary cooler without bypass and use an inline 180° thermostat valve?

 

Here is the idea drawn out in two scenarios. Keep the OEM Cooler and add a New Cooler inline with the 180° Bypass Valve. Theory is the OEM Cooler is backed up by a Redundant New Cooler once fluid temps go over 180°. Fluid stays at 180° in all seasons/driving conditions.

 

It's a great plan and in theory it's totally usable. I wish I had thought of that before I did mine but I've talked to a few very versed transmission guys now and they all say that 130-150° is an excellent operating temp especially on a sealed transmission. The general consensus is that 180° was the optimum operating temp on older vehicles but now with ECM controlled systems and modern sealed trans the cooler the better. I'll be the test rabbit and let you guys know how my tranny is going after I put 15k on it before the year is over. It really does seem to shift smoother. Keep in mind that on the torque app it is reading from the pan and not the converter so my guess is it would be closer to 25° +/- warmer than the pan thus putting it in an optimal operating temp with pan reading 130 to 150. My 2c

 

Mine does seem to shift smother as well. 1-2 has been firm but if it wasn’t for the RPM gauge and exhaust, it would almost go un-noticed on the rest of the shifts.

I think it’s a great idea but it wouldn’t be something I would tackle. I’m happy with my current setup, especially for the ease of installation and cost ($50).

Now can anyone tell me we’re the hard line mounts? Don’t laugh, but I must be over looking it. The only place I think it could is the bottom of the radiator bolt mount?

 

I'll get a picture of mine for you tomorrow

 

Thanks. I looked for a long time last night for a set up as I’ve drawn above. Couldn’t find one. Probably for a reason.

In theory it is doable. I’ll keep this on the back burner. Might not ever do it, but at least it is a workable idea for around $180 in total cost.

 

It mounts up on the lower portion of the engine block I believe. There should be another bracket like it (horizontally back) towards the rear of the engine.

 

Just remember the reason 170-180 is ideal is the transmission is designed to run around that. Metal and fluid expands as it heats up. When it’s cold the fluids a little more resistant to flow and the valve body vanes are a bit more restricted (if you have had a 1st gen Tacoma you know they don’t shift into 3rd easily till the trans is up to temp)

 

Well I asked another group and they said there is a hole on the frame. I found a bolt that fit so I’m not sure it is right but snugged up nice and seems to be aligned correctly?

 

I also got my mountain run in today and I have to say, I was a bit surprised. It mostly sat at around 160* until I started heading up the pass. It’s a 65mph speed limit, all up hill. Of course no one goes the speed limit and is running 70-80mph. I was pacing traffic and I remembered to check it and..


That was the hottest it got. It floated around 180* +/- 15* the whole way up. Once I got into town, it settled to 170*. This makes me wonder what it was running previously before I made the swap, 200+? I drove all day today and once it was fully warmed up, it sat averaged 160* for the most part. Kind of makes me wonder what the magic number for the dummy light is set at.

 

i think thats the wrong hole... the one you need has a little hole next to it for that ear on the bracket

 

This hole?