Gevo

FINALLY, got around to this. Took a tranny oil temp warning light on my dash to do it

I purchased the Auto Meter basic oil temp gauge and the B&M oil cooler below:




Cleaning the skid plate to paint for some rust prevention. Later found I'm out of rust-oleum.. booo I'll get back to that.


After some research I thought I will be better off to get some brass piping items to mount the temp gauge in. The alternative was to buy the auto meter manifold, $35 vs the $12 I spent. I wish I had a lathe, I would be machining my own awesome little manifold.

I took a look at the grill cuts in the skid plate and tried some rough testing to see how well the air will flow into the oil cooler which I planned to mount behind it (using garden hose and finger to spray). I found that the water flow straight through, but doesn't change direction slightly upwards, which is what I was hoping for. The oil cooler would have to be mounted slightly above the openings in the skid plate (or so I thought at this point), either way I adjusted the grill cuts to make them have a larger opening, and I also achieved a few degrees of angle change between the water going in and out of the skid plate. Success. Funny thing, after my final mounting position was decided, I readjusted all this to a more straight through opening, almost to stock, just bigger openings. So, time not so well spent. lol.

So, after a lot of trial and error... meaning temp mounting of cooler, installing skid plate, removing, remounting, re-installing skid plate... I was able to come up with a good location and angle for the cooler. I had to keep it away from the steering components and also as far away from the skid plate as I could in order to avoid any offroading mishaps damaging the cooler, leaking tranny oil.. etc. These two pics are of the second to last and final mounting position.



After that, I realized I had a bit more clearance and was able to move it closer to the steering components. This also allowed me to mount the cooler closer to vertical, which will result in the best air flow through it and also not direct the warm air into the engine bay. Although, the aerodynamics of the engine bay are very difficult to imagine and understand. I'm pretty sure it's a huge turbulent mess in there. And I'm pretty sure the front bumper and flat face of the 4Runner isn't going to provide laminar air flow as my garden hose assumed. Basically, I feel there is a near future need of a fan to help draw the air.

Anyway, here are some more mounting pictures. These are in the final position, with the hoses in place. It was a squeeze getting the filter and brass fittings on the in-coming oil line.




Also, I tried to bend the mount in such a way that in case of the skid plate landing on a rock and going up far enough, the cooler mounts would bend for some additional movement. SO I tried to make nice clean long bends. I need some shorter bolts.





I put some heat protection on the hose nearest the bottom of the radiator.


Final. Left it this way, ran out of time. Have to do wiring and install gauge on dash.


SOme thoughts; I'm glad I didn't have room enough to mount it in front of the a/c condensor and radiator as others have. I am paranoid about the engine not overheating, or even maintaining as much cooling ability as possible. I say this because the B&M cooler restricts the airflow through it QUITE a bit. Also, it angle the outgoing air about 45 degrees in the lateral plane. This is good for it's own cooling ability, but no so much for the radiator behind it. Once I get the gauge installed, i'll be able to determine if I 'need' a fan on the tranny oil cooler or not. People here say they are able to maintain 170 to 200 degrees with the coolers during lite offroading. If I can maintain the same without a fan, that would be great.


OK. Any thoughts, comments, suggestions.. go ahead

JasonYota

iTrader: (1)

Good install! Never though about mounting one there. Any pics of the gauge set up inside?

Gevo

Haven't done the gauge mount and wiring yet. Hopefully tomorrow, my day off from work.

This was at first out of necessity, but as I wrote above, I prefer now not to mount it in front of my radiator anyway.

Gevo

I completed the rest of the installation a few days ago and now have been running it since. I am not completely sattisfied with the outcome. During hot days (it was just about 100 yesterday) on the fwy at about 50mph, it would steady out around 180 deg. Then when a little acceleration is needed and the torque converter unlocks, that sucker shoots up to 200. I know it's not getting the best airflow over it, but i have NOT mounted the front skidplate yet. I wanted to test with and without it. I'll mount that soon and see what the difference is. But, if It wants to stay at 200 degrees often, I'll be putting a little electric fan on it for some well directed air flow.

I took someone elses idea from here and mounted the gauge as shown.

RSR

You're absolutely going to need a fan in that location.

Also, you should be seeing lower temps than you are IMO.

See this thread (for next gens but a lot of useful info there): https://www.yotatech.com/forums/f2/b...3/index22.html

Also, in regards to heat from tranny -- mounting the cooler in front of your condensor will not increase engine heat. In fact, a external tranny cooler cooling fluid before going into stock radiator actually turns your tranny fluid into a heat sink for the radiator fluid. A net positive for your engine...

There's not room to mount this vertically on your drivers side in front of condensor?

Marc

You could always bypass the cooler and then check your temps.
That will let you know how effective the current cooler setup is.

Gevo

RSR, I hadn't thought of it as a heat sink before, that is interesting, as long as the temperatures of the oil cooler aren't to to high.

My concern was mostly from the flow of air prospective. The B&M cooler is very dense, and redirects the flow of air about 45 degrees in the lateral direction. And, it's not all that small either, perhaps I got the 'wrong' size for fitment purposes, but it will take a good amount of good air flow away from the radiator.

But, to answer your question, no, it simply would not fit infront of the radiator in any orientation. The refrigerant lines are in the way.


Marc: I have the temp sender at the inlet to the tranny cooler, before it cools. The idea was to get to see the highest temperatures seen by the trans.

I do have half a thought to install a second temp sensor in the outlet line, mostly for fun, but also as you mentioned, to see the amount of cooling. I believe with a fun switching system I can use one gauge and two sensors/senders.

I am going to look for a slim fan, at the minimum I am sure it will be required for offroading.

JasonYota

iTrader: (1)

Another idea for you and others, when I install a transmission cooler on my 4runner it will be mounted somewhere flat under the body with a fan. Sort of a "rear mount" cooler.

Yotard

I mounted my cooler in front of the radiator and I mounted my gauge on the transmission output to the cooler and I see the exact same temps. 180 in lockup and 210 climbing hills or accelerating out of lockup. The high stall speed on these converters produce a lot of heat.

RJR

Do you know what the maximum recommended temperature is for the transmission fluid, or at what temperature the light comes on? 200 degrees going into the cooler doesn't seem all that hot. Most lubricants benefity by getting above 212F periodically just to boil off the condensed water in the system.

JasonYota

iTrader: (1)

I've always read/heard around 190. The hotter it gets the faster it breaks down the fluid. About the condensation, as long it gets warm enough for long enough to remove any moisture it's fine. Doesn't have to "boil". Trans fluid and antifreeze won't boil at 212 anyway.

Yotard

the idiot light is set for 300F which the fluid is done when it gets that hot. Toyota didn't properly design the transmission cooling system by just using the radiator. My trans temp idiot light came on for the first time with stock tires climbing up to donner summit on hwy 80. I added the cooler in and not only does it not get over 210 maybe 225 for short periods but I haven't turned the idiot light on ever since and I am running 32's now.

RJR

Here's a bit more information on transmission temps:

This from General Motors:
From the 99 2500 Sierra owner's manual.

"If your vehicle has a heavy duty automatic transmission, you will have a transmission temperature gage.

When your ignition is on, the gage shows the temperature of the transmission fluid. The normal operating range is from 100*F (38*C) to about 265*F (130*C).

At approximately 265*F (130*C), the message center will display a TRANS FLUID HOT message and the transmission will enter a transmission protection mode. When the transmission enters the protection mode, you may notice a change in the transmission shifting patterns. The transmission will return to normal shifting patterns when the transmission fluid temperature falls below 260*F (127*C).

If the transmission fluid reaches temperatures of approximately 275*F (135*C) or greater, the message center will display a TRANS HOT...IDLE ENG warning message. Pull the vehicle off the roadway when it is safe to do so. Set the parking brake, place the transmission in PARK (P) and allow the engine to idle until the transmission fluid temperature falls below 260*F (127*C). If the transmission continues to operate above 265*F (130*C), please contact your nearest dealer or the GM Roadside Assistance Center."

Doing a bit more research on this, the general consensus is that the rate at which standard, mineral oil based ATF degrades doubles for every 20degF above 175 degrees. So, a fluid that will last 100,000 miles at 175F will last 50,000 miles at 195F, and 25,000 miles at 215F. That seems dramatic, but keep in mind the effect is cumulative over time, so if the fluid only gets hot once in a while, it's not that big of a deal. For example, if you hit 215 deg for 5% of your driving, you should change your fluid at around 85,000 miles instead of 100,000 miles. Synthetics resist high temps better, so the doubling effect doesn't come into play until higher temps, maybe around 225F or higher.

Keep in mind also that automatic transmissions don't like cold fluid, either. It needs to be upwards of 150F for proper shifting and valve operation. That's why transmission coolers are normally run through the radiator - during cold weather the radiator actually performs the function of warming the fluid for better transmission operation. It also appears that most factory installed auxiliary coolers have a thermostat which bypasses the cooler until the fluid gets to 150-160 degF.

Gevo

Great stuff, I appreciate the discussion!

Before I forget, the B&M cooler claims it has a built in low temp bypass, so that's covered.

Now, I had read that above the 175 deg mark the fluid starts to degrade rapidly, and now without a fan (or the skid plate yet) I am running above 200 about 20% of the time. Before the install I thought I had a chance not to 'need' an electric fan, but now I'm convinced I need one. First of all for offroading, less air-flow, higher revs.. etc... and then for that 20% above 175 on hwy, and maybe even more on city streets.

One thing to point out, I did NOT route it through the regular radiator oil cooler portion since I broke one of the nipples. I will repair that nipple, run without a fan for a few days and see what the difference is, if any.

I got the tranny rebuilt about 6000 miles ago, and a month ago the shop who did the work went bust. My 12000 mile warranty and a trusty shop is gone now... either way, I want the best protection/operation of the tranny. A few bucks spent now may save a lot later.

After all, even if you change oil more often, the warmer running parts fatigue and wear faster.

I'll hook the radiator cooler in line and report back soon.

JasonYota

iTrader: (1)

With the internal thermostat in the B&M cooler there is no need to route the fluid through the regular radiator.
Mine is routed this way though I have a cheaper tube style cooler without a thermostat.
Also to aid in warm up the ECU leaves the torque converter unlocked until a certain temp is met.

rworegon

Just as a point of reference from the 1995 Tacoma FSM, it states the normal ATF operating temperature for the A43F, A340E, and A340F auto transmissions is 122-176F.

Other Toyota auto transmissions are likely in a similar range.

Gevo

JasonYota, my goal in routing through the radiator is for cooler temps, in the morning, it doesn't take much to warm up to 115 degrees + . Although, I also need to get a hold of a laser thermometer and check the temperature of the brass fitting that the temp sensor is mounted in and compare with the gauge readout... Perhaps as I believe RJR mentioned earlier, it is not the correct reading...

rwOregon, that is about the range I have been reading as well. The Autoshop documents say 158 to 176. So, my ultimate goal is to keep the temp in that range during any driving activity. http://www.autoshop101.com/forms/AT11.pdf

So, As I am writing all this, I'm wondering what the output temp of the engine coolant is through the radiator? If the engine is maintaining about 200 degrees at the manifold, it follow to assume that the output temp of the coolant from radiator is significantly less than that... wondering, how much real benefit is there from routing through the radiator oil cooler in series... anyone know exit coolant temps? Can't find much online.

RJR

I think the primary heat generator in an automatic transmission is the torque converter, when it's not in "lockup" mode. Under those conditions there's a lot of slippage which turns into heat. So I think you're wise to plan for managing the heat during offroading, because for sure the torque converter is going to be in "slip" mode a lot of the time, especially going up steep hills at slow speeds.

My first 4wd vehicle was a 1976 F150 pickup with a 3-speed automatic, a 3.73 rear end, and a 2:1 transfer case, for a measly 19:1 crawl ratio. The only thing that made it work was that big V8 up front with a boatload of low-end torque, but on steep offroad hill climbs you could smell the transmission fluid cooking as the torque converter was nearly stalled for minutes at a time. I never measured the fluid temperature, but I'm sure it was hitting 300+ degrees. Fortunately, I traded the truck off before the transmission bought the farm.

Gevo

Ron, I have a feeling the ford tranny was more tough than these toyota trannies. But, nonethless 300 degrees apparantly is the end of the oils life.. so.. good thing you got rid of it

I need to do research now and see what the best cowling vs. Ele fan setup is for this situation. Find a thermostatic switch with the right temp range, wire in a manual switch override and go offroading to test

If its not this hobby, its something else... love it !

RSR

A lot of this discussion is redundant on this thread: https://www.yotatech.com/forums/f2/b...3/index21.html

Temperature:
Maintenance section of FSM says this for auto tranny temps:
Further: