Trans temps higher after skid installed.

[SIKHILUXSURF]

hey guys just installed my Budbuilt skid plate this weekend. and after i put it on i noticed that the trans temps were up during normal driving. and when climbing a hill over the weekend my temps shot up to 205 max climbing up the hill.

for you guys with aftermarket skids and trans coolers did you guys notice your temps go up? did you guys do anything to help aid your transcoolers?

 

[quicksilvr]

I can't help with the transmission temperature issue...but what is that very slick oil drain setup!?! Is that how they are all made now? Because THAT is sweet. Much better than the tiny little hole.

 

[DC runner]

Honestly, this is to be expected. You essentially built a wind proof cage around your transmission. You reduced the total airflow that moved over it. While most of the cooling for the transmission comes from the cooling system design, the laws of thermodynamics and temp transfer tell you that any air moving over the trans itself will help in cooling.

By essentially putting a huge air block up, you reduced your total cooling by some percentage.

If you are concerned...make large slits in the armor or install an aftermarket trans cooler to make up for it.

Also, do we no longer teach basic thermodynamics in school anymore? I feel like this was something covered in High School. If we don't I guess this is why we are falling behind in Science and Math. I guess we stopped teaching it.

The same principle that makes your radiator work (heat transfer) works directly on the engine and the transmission. The cooling system acts as a indirect cooling system... but remember, for the first 50 years... cars were simply air cooled. It worked quite well as long as you could keep the car moving. The problem arises when you have to STOP and keep the engine going. Water cooled helped fix that, but the point remains, direct air cooling is pretty powerful.

 

[SIKHILUXSURF]

yes i do realize that. i actually do have a trd transcooler installed on the truck as well but i wanted to get some feedback from other people with the same type of skid plate and what they did if anything.

 

[the great him]

two things, first yes the skid is blocking the air flow to the trans and motor so temps will increase, and second now you are hauling around that much more weight, those budbuilts are not light skid plates, so its almost like always having another person in the rig with you... the combo of the two will be enough to make a noticeable difference in trans temps... that is one of the reasons i went with dual coolers...

and yeah whats with that removable center section in the skid!? WTF is that how they are doing them now, i might have to buy a new skid plate and sell my old one, cause thats so much nicer than having to take my skid off every time i want to change the oil...

 

[SIKHILUXSURF]

two things, first yes the skid is blocking the air flow to the trans and motor so temps will increase, and second now you are hauling around that much more weight, those budbuilts are not light skid plates, so its almost like always having another person in the rig with you... the combo of the two will be enough to make a noticeable difference in trans temps... that is one of the reasons i went with dual coolers...

and yeah whats with that removable center section in the skid!? WTF is that how they are doing them now, i might have to buy a new skid plate and sell my old one, cause thats so much nicer than having to take my skid off every time i want to change the oil...

hey i have a few questions for you. what are your temps like with dual coolers? how many quarts of ATF are you running in your setup?

as far as my skid i paid an additional 100 bucks to have the door done.

 

[DC runner]

I don't know if I would consider the weight a variable at play. That armor weighs less than your average passenger. That 4runner was designed to haul 5 people, and to do that with the trans temp within safe limits.

No., The real culprit in the increase in trans temp is the loss of a large surface area for convective heat loss. Convection is an extremely powerful heat transfer method. Convection is how literally every modern cooling/heating system works. You heat your house by heating up a coil and running air over it, into the house. The AC works the same way, only with a COLD coil. Your transmission pan is about 2 feet long, and that surface area represents a large area for convection to occur. The "wind chill" effect you feel on your bike when you ride down a hill, well image that on the underbelly of your trans when you drive at 60 miles an hour. You bet it has an impact, and that is, in my opinion; why your temp is up.

I am willing to bet that if you drilled large slits in both the front and rear of your armor (to allow the wind a "channel") you will drop your trans temp back down to what you expect.

If you look at OEM armor, it always has air channels in it. Go buy a cheap dremal tool or a angle grinder and make your self some long, narrow channels like you see on your OEM from valance. Then, also make similar air channels on the backside of the armor.,
You have to make sure you create a path for the wind. Just making slits in the front won't do anything... convection is all about the air MOVING over an area. Not still air.

You could add an additional cooler, but from an engineering standpoint: Giving the trans that second method of cooling will help fix hot spots.
Just my somewhat educated opinion on the subject.

 

[the great him]

hey i have a few questions for you. what are your temps like with dual coolers? how many quarts of ATF are you running in your setup?

as far as my skid i paid an additional 100 bucks to have the door done.

idk how many qts, i have not done a full drain of my system yet. i think i added like 2.5qts all together so... as far as my temps, i generally see around 140-150 on the hwy and can see up to like 180 climbing hills, if i really get on it or load things up i have seen way over 200, but thats like been far beyond "normal" driving. and when i wheel it i can see over 200 as well as stop and go traffic.


im not going to get into another "discussion" about trany temps and what affects them, bottom line is added weight affects it period. yes the 4runner was designed to haul 5 people, and tow... but no it was never tested in this manor. no vehicle is. engineers do not go load 5 people into a car and drive it around for hours at a time trying to find things wrong with it. this stuff is all based off of computer models that say "it should work" and that only is under ideal conditions, not taking into account, hot days, high humidity, extra load on the vehicle ect. bottom line is added weight will affect how hard the trans will work, just like bigger tires will have an affect on it

 

[Dous]

I had a thought, still haven't done it yet, but one day i might.

I have a huge fan from a Ford Taurus, the ones people use for the E-fan swap, there is enough room between the sump pan and the belly skid for it to fit (I think).

That fan moves a crap ton of air, I think it might help bring the temps back down.

 

[Singtoe]

I had a thought, still haven't done it yet, but one day i might.

I have a huge fan from a Ford Taurus, the ones people use for the E-fan swap, there is enough room between the sump pan and the belly skid for it to fit (I think).

That fan moves a crap ton of air, I think it might help bring the temps back down.

Sounds like your making a hoover craft.


IMHO cooling the trans itself would cause more electrical use in turn generate more heat via the alternator and the motor generating more heat to generate more electricity.

Put a little fan on the transcooler. if needed.

 

[Dous]

Sounds like your making a hoover craft.


IMHO cooling the trans itself would cause more electrical use in turn generate more heat via the alternator and the motor generating more heat to generate more electricity.

Put a little fan on the transcooler. if needed.

Good point, I will never do it anyway, I hate dropping those skids.

 

[chimpy]

hey guys just installed my Budbuilt skid plate this weekend. and after i put it on i noticed that the trans temps were up during normal driving. and when climbing a hill over the weekend my temps shot up to 205 max climbing up the hill.

for you guys with aftermarket skids and trans coolers did you guys notice your temps go up? did you guys do anything to help aid your transcoolers?

:jaw drop:That thing looks like it should have BRINKS written on it. Very heavy duty indeed.

 

[Stick Figure]

too bad you can't get your hands on some nice carbon naca ducts to direct air on to that trans!

I bet that would keep it nice and cool! :lmao:

 

[Dous]

too bad you can't get your hands on some nice carbon naca ducts to direct air on to that trans!

I bet that would keep it nice and cool! :lmao:

Obviously you aren't very well versed in this subject matter. There is a much cheaper way of doing this.

The great thing is, these can be had at your local Vatozone. Provided the Honda drivers haven't already picked them over.

 

[SIKHILUXSURF]

too bad you can't get your hands on some nice carbon naca ducts to direct air on to that trans!

I bet that would keep it nice and cool! :lmao:

haha Brandon its funny you brought those up. i though about them but,

one i would have to cut some huge holes to make em work. i pulled them from the shelf and took a look at one lined up to the skid and its alot of cutting to fit it.

two i would crush the naca if i hit a rock or went over something.

 

[fish0281]

As someone who has masochisticly pursued various heat transfer topics in college/grad school, I'll give you my $0.02:

While there is heat transfer from the body of the transmission to the surroundings, it is the convective cooling at the radiator that provides most of the heat exchange. Have you noticed an increase in engine temps too? I'm wondering if the skids are preventing sufficient air-flow through the radiator itself? That thing looks like it'd prevent a lot of air-flow through the engine bay (and, hence the restricted flow through the rad itself)...

The increased weight of the plates themselves in principle will cause the tranny to work harder, but it will not cause that dramatic of a change.

 

[Stick Figure]

Obviously you aren't very well versed in this subject matter. There is a much cheaper way of doing this.

The great thing is, these can be had at your local Vatozone. Provided the Honda drivers haven't already picked them over.

You kind of missed the inside joke here, the original poster has less traveling to do to get the carbon naca ducts than the auto zone crap.

haha Brandon its funny you brought those up. i though about them but,

one i would have to cut some huge holes to make em work. i pulled them from the shelf and took a look at one lined up to the skid and its alot of cutting to fit it.

two i would crush the naca if i hit a rock or went over something.

yeah those do take some huge holes, its always lots of fun to cut up a bumper or something for those.

While there is heat transfer from the body of the transmission to the surroundings, it is the convective cooling at the radiator that provides most of the heat exchange. Have you noticed an increase in engine temps too? I'm wondering if the skids are preventing sufficient air-flow through the radiator itself? That thing looks like it'd prevent a lot of air-flow through the engine bay (and, hence the restricted flow through the rad itself)...

The increased weight of the plates themselves in principle will cause the tranny to work harder, but it will not cause that dramatic of a change.

Since the skid starts after the radiator I can see 2 potential causes for the issue if its radiator/cooler based.

The stock skid drops lower right away which may act as a small front splitter pushing air up into the radiator. Similar to how a trans am or corvette cools the radiator with out a front grill opening.

The other option would be not allowing the air out of the engine bay once it has passed through the engine bay. You cold always do a quick test by shimming the back of the hood or removing the weather stripping at the back edge to see if it lets more post radiator heat out. Of course that hot air will pull into the cabin through the cowl vent so your AC may suffer a bit while your doing that.