I've been thinking, I see a lot of threads devoted to the management of engine oil temps and cooling system temps but I never hear about trans temps.

Maybe it's just because of how I was raised and taught to build cars... but all of our high horsepower/rpm street cars as well as our road race and purpose built drift cars have a transmission cooling system and a differential cooling system.

And our RWD cars have larger transmissions with larger fluid capacities as well as more surface area to dissipate heat and we still have heat issues. Same thing with differentials, any kind of hard driving/abuse seriously heats up the gear oil.

So my question is this.

Has anyone ever monitored manual transmission gear oil temperatures, whether b,d,k, or h on our FWD platforms?
If so, what range did you see under what conditions?
What kind of system are you using to control temps?

The way we normally do it is drill the bottom of the case in a location that always has oil present, no matter what kind of driving. We then run a braided line through a filter and then to a tilton or similar scavenge pump, feed it through an oil cooler (cooled by direct airflow from the front of the vehicle or fed with a high rpm/flow brake duct fan) we then pump the oil back to the transmission to the top of the case so it showers the gear set.

Looking at a typical b series turbo application, the underhood temps are high (just see the heat management thread on this page) not only do you have residual heat from the motor but you've got radiant heat from the downpipe as well as the radiator/intercooler flowing straight into and around the transmission caaes. Not to mmention heat from the gears turning, high loads, etc. You also have a differential in the same space sharing the same lubrication oil. I don't see how temperatures aren't high.

I have a few spare tilton scavenge pumps laying around and had a few ideas on how to make a transmiaaion cooling system work on a FWD Honda/acura.

The best place to draw fluid from the transmission IMO would be to modify the drain plug with an AN fitting.. as low as possible on the plug to ensure you remove the majority of the debris, or machine a new fitting with an AN fitting integral to the piece (it would likely need to be centered if being machined) as no two transmissions are threaded the same and the fitting could wind up at the very top) and while not optimal it would still get the majority of debris out of the case.

It's either that or drill a hole below the drain plug and weld or thread in an AN fitting, although for experimental purposes I don't want to go drilling into cases.

This oil would then be pumped through a reusable/cleanable stainless steel low micron single or dual stage filter assembly. The dual stage might be better as you have ,ore filter area to better screen debris and not clog a fast as a single stage. Some sort of valve would be on either side of the filter so you can close them to facilitate filter servicing/evaluation without having the drain all the gear oil.

It would then reach the scavenge pump and from there one of two things can happen.

1) trigger the pump with a temperature switch mounted directly to the transmission (not sure if heat soak will cause premature activation of the pump)
2) have the pump wired to a switch in the car or hardwire it to a switched power source

If #1 is chosen, fluid will go straight from pump to cooler
If #2 is chosen , fluid will circulate constantly but a thermostat diverter assembly will be in place to bypass the cooler until a pre defined temperature is reached. The benefit to this is fluid is constantly being filtered whether its cooled or not, which would greatly help synchro life. Once the pre defined temperature is reached, the thermostat assembly allows oil to pass through the cooler.

Now here's where I'm kind of stuck.

How to return fluid to the transmission, logic says use the fill/level plug on the side of the transmission. There's one slight problem. The lines, pump and cooler will add volume to the system, requiring you to fill the trans like normal, run the pump system and add fluid until the proper level is attained.. the problem is with the side plug being removed to check fluid levels is you'd have to get creative to still pump the fluid back intothe trans without mmaking a huge mess.

Also my concern is that given the fill level plugs proximity to the drain plug/scavenge pump source location, is that most of the same fluid would get filtered over and over again, still leaving hotel potentially debris laden fluid in the case.

Now one could simply drill a hole in the top of the case and return it that way. However again, being an experimental setup (at first) I don't want to go drilling random holes.

Maybe I'm over thinking this, I'm not sure... but I feel it would be beneficial to filter/cool the gear oil in a high horsepower boosted FWD setup, whether a street car or track car (mostly circuit/road racing, I don't see the need for a drag car to have a cooling system due to the short duration of use)

So

Thoughts
Opinions
Advice
Input
?

Thanks

Also, if anyone has done something like this, please share photos/ specs/experiences.. I'd like to hear what people have to offer

 

It's a good post.
I do get what your asking, but in away it almost "over-step" the basic questions that people tend to start with such as:


1) what are normal MTF opperating temps & what are general temps in some racing applications?

2) what are honda MTF temp rated for before hey lose their lubricating properties.

3) IF OEM MTF is not good enough, what are other MTF fluids out there that other are using with good results?

4) Has anyone encoutered tranny failure strictly to heat related issues (not power)?



I just don't want you to over think the "how-to" unless you know if there is a consensus that MTF temp is an issue with boosted hondas.

 

Awesome questions, Charlie. I have found on other applications such as R34 Skylines, SR20DET and EJ257 Time ATTACK cars, for sporting applications, that temps can just be super high from endurance racing, not based upon power level. The exception are from truck applications that experience HIGH levels of engine load that transfer to the transmission or transfer case.

For Hondas, We don't make enough engine load torque, nor go through transfer casings to transfer the fluid to really warrant the expense and use of transmission coolers, although I suppose any amount could theoretically help. Our B-series and K-series transmissions really were designed for fluids much like engine oil,which still experiences less heat on average than the transmission. Now.. How that translates to any practical use only the strong at heart can experiment with, but I haven't seen the real need for them even in endurance racing due to the design of the materials, gearing and placement of where the fluids interact.

For those with clutch-type LSDs (I'm not worried about the clutch itself) using the right gear oil IS PARAMOUNT in making sure that not only will the plates break in properly, but that GL-5 fluid temps stay lower. I'm talking with a couple of professionals that are making their own mixes to better those transmissions with Clutch-type LSDs. I won't divulge on their contents of what they're considering (that's not fair to them) but it'll be nice to venture into this area as I'll be eventually converting my Integra to AWD.

I guess if people want to try it, go ahead, but for the average drag /street racer around on this forum, its serious expense that only the cavalier should attempt.. But it is worthy of further discussion...

 

What's Honda mtf? Acdelco syncro mesh makes the car drive like a new 7 series

 

Honda MTF... is HONDA'S MTF.. They have their own blend.

GM syncromesh has done wonders as well. Not sure about the AC Delco version.

 

Manual transmission fluid....

I don't run OEM fluids, never have, never will... I already know I'm gong beyond their service limits.
I normally use GM synchromesh in my boosted transmissions, helps with the drivetrain shock.


Generally (I use that term loosely) more power equals more heat as the transmission experiences higher loading forces, the added torque and rotational forces (face it, we drive turbo cars harder than we ever would a naturally aspirated car) equals more friction which means more heat. Also given that most people run thicker gear oils to help protect transmission internals also equals more heat due to thicker oils adding more friction (normally) that's why cars that go from OEM weight gear oil to say, synchromesh, experience a power drop... the thicker fluid clings harder to gear surfaces which means more drag, which means more friction which equals heat.

See what I'm getting at? Friction is the enemy but ultimately inevitable when dealing with heavy gear oils.

Again, the typical street/drag car won't really see elevated trans temps, not even people that autocross. Because the driving event is such short duration that it doesn't really matter.

Now in my case I do a lot of mountain runs... and we drive our cars hard in the mountains. We also have a membership to Atlanta Motorsports Park, so I will be doing a lot of hard circuit driving, we also do Road Atlanta and Barber... again hard, extended driving, especially RA and AMP, they are two very fast, aggressive tracks. Barber is really hard on tires and brakes but you can basically do the track in 2nd and 3rd.

I don't honestly know if anyone here could say what average transmission temperatures are because since I joined this site I've never seen a setup nor anyone mention this topic. We can ***-u-me that the transmission temps reach those of similar manuals, given similarities in oil viscosities but having the differential in the same housing sharing the same oil definitely adds more heat.

And if not for cooling, running the fluid through a filter will definitely help extend transmission service life as well as well as protect internal components from synchro debris.

I think it will be interesting once I get the car done, I'll do a temperature datalog of transmission temperature with no cooler under various driving conditions and then one with... but remember using a thermostat system only allows oil to enter the cooler once a certain temperature is reached... so it would still be good insurance were temperatures to rise very high

 

Also, remember that the transmission case itself will absorb surrounding heat, which can also cause premature temperature increases. Also just by the gears turning the fluid gets moved through the transmission and cools by evaporation. Once again, typical street/drag/autox setups have enough no load/partial load events to facilitate cooling.

Power levels do come into play somewhat... the average stock internal sub 300hp builds really don't need it but once you start getting to the 400+ range one can assume you're going to drive fairly hard and have built the car for a purpose.... knowing people on this site I can bet 99% are for drag racing. The other 1% though need more attention to small details because going around a track at speeds over 1mph for extended periods of time, plus rev matching on downshifts/engine braking, plus flat shifting, heel toe, etc all add additional stresses to the drive train and the first places this stress is seen are normally the axles and transmissiin,.

The rule normally goes if the axles don't brake first, the transmission will.

I'm just trying to cover all aspects of the build to ensure maximum reliability and efficiency. I don't like pulling motors, swapping transmissions, clutches, etc. I'd rather overbuild it once and be done

 

wantboost - You should search better...

https://honda-tech.com/forums/road-racing-autocross-time-attack-19/transmission-cooler-installed-2768707/

TheShodan - What AWD setup are you considering? Sticking with a Honda platform or something else? If Honda, the viscous coupler or the dual pump? Reasoning behind your choice?

 

I can tell you that typically we never want to see above 175 for automatic transmissions. Not sure how that applys to MTF though.

 

i have monitored the manual trans temp on my 400hp z6 before.. i bout a trans temp gauge. i installed the probe in the drain plug. trans temp gauges are pretty much for automatic transmissions because the gauge starts out at 100 degrees..i monitored it for a few days and made alot of pulls on the highway and such and the temp may of just barely got over a 100 degrees at the most. and yes the gauge was working correctly. i learned that no matter what i did the manual trans fluid never got hot so i have since taken the gauge out of the car since it is not needed.

 

To the new guy, thanks for the link but don't be a ********. Pretty much confirmed exactly what I thought in the first place. I don't spend time in any other sub forum.

Like I've said before, street cars don't need anything like this, on city streets you can't legally or even begin to drive hard enough to raise temps, nor will any drag car.

My car is more than a street car, I do track days at road courses, temps will soar

 

I know it'll still be with the Honda platform utilizing the B-series engine. But I'm still in the midst of my investigations with a few companies and engineers (not just "shops") to narrow my approach. This won't be for another year or so of additional work. I've had the car 15 years. Another 1-2 won't hurt anything.

 

Why do I think I smell a Weismann transmission/transfer case lol

 

Gm synchromesh is made by acdelco. I started on hmtf that is ****. My gears started going in weird and knotches racing. This tranny is my baby I put that fluid in and it's been ran and raced for 4+ years. I run it in my Gsr trans and it dries even better since it has less abuse.

There's less pumps and systems in our tranny I don't know much of the science behind it all but keep a good fluid and don't miss treat it the trans will last a long time. And this is racing once its pooched u rebuild it.

 

I havent found a fluid I'm in love with yet but so far this time around im runnign valvoline VR1 straight 30 weight in my transmission (non-syntheitc) and it shifts smooth as butter.

 

As for fluid and don't want to beat this to death. I asked synchrotech what fluid should I use (just recently bought there carbon rebuild kit and LSD) they said honda mtf or torco mtf

 

and i have always ran 10w30 motor oil. Never once had an issue.. YET, i guess?

 

I'll be putting half Honda Half Redline shockproof when my trans is done

 

a few years ago i was rebuilding b series transmission on CL. I advertised there. I had a abundance of parts so i was fixing trans for about 300$. I know I saw a few come in that had super thick oil in them, that had cause premature synchro wear. The best was a JDM ITR trans with LSD and 4.7 final that was grenaded due to the idiot running straight ATF in it.
So as far as hot temps, I never saw any transmission that looked like they had excessive heat at any one point. I.E. the changing of color due to high heat.
I did a lot of these any any of these people road raced their cars, not saying this is the best info, just my experience.

 

Fluid choice is huge, some people pick thicker fluids because it protects better but at the expense of quicker wear

Here's another good question, who has seen transmission failure due to fluid contamination? Like fluid breakdown, debris,etc. Because even running the fluid through a proper filter element will remove most contamination, to a point.

Like I said before, on the cars that don't see excessive heat build up at least filtering the fluid will be beneficial. But as the link above shows, cars that do a lot of road racing will see a huge temperature build up.,, fluid at 300 degrees is degrading super fast and could cause improper lubrication due to excessive fluid thinning.

 

While I have not measured fluid temp, I know that the typical d,b,h and K transmissions will run very hot on road racing/trackdays. A few things I have noticed over the years:

-Oem, basic synchomeshs like pennzoil, gm etc work best for daily driving duty and fairly low powered street cars.
-higher powered turbo setups ~ 350/250 tq and up cars will start showing wear on gears with oem type fluids
-Road racing and track days will deteriorate and overheat the oil pretty rapidly. K-series cars will have a very short life to gears 2-5 and final drive if you run oem type fluids
-Redline shockproof works amazing to cushion and protect gears from wear and breakage, but this has mixed results on synchro life and usually requires more gearbox inspection and servicing.
-motul ff fluid seems to work very good on street and track car even with older oem synchros, no experience with high power cars on it.
-Too many people neglect the transmission and its fluid, and dont seem to acknowledge or realize that they are a maintenance item and need fairly periodic overhauls and "freshening"

 

^exactly, each fluid has a very specific use
And you're also correct, a lot of people do not realize a transmission is a service/maintenance unit. Every hard shift, missed shift, grind, etc all introduces various materials into the fluid, from brass pieces off the synchro to synchro material itself, as well as debris from the gears. This needs to be addressed especially when doing something strenuous like road racing, as elevated temps and debris in the fluid will cause premature wear and eventually lead to transmission failure.

We use royal purple in our RPM stage 5 tr6060 is the z06, which also happens to have a transmission and differential cooling setup, all of which have internal pumps and feed a cooler at the front of the car,

I have 2 tilton scavenger pumps laying around, as well as various an fittings, 2 billet aluminum remote oil filter blocks from HAAS racing which have ports for pressure, temp, i had planned in using both for the motor, with two different filter medias for each filter mount. If i cant find these I'll pick up a dual filter inline unit

also i have aluminum hardline in various diameters (as well as a bending tool) that i would use for plumbing to and from the oil cooler on the chassis side and connect these to the motor side with braided line, as well as having braided line, kevlar line, etc from previous products. I had a setrab cooler that was perfect for transmission duty but a friend needed one for his lsx swapped s13 that he drifts so I let him have it, luckily I know where to get them cheap.

I also have my transmission in the garage and I'll be looking for the best way to draw fluid from the trans as well as return it. I'll post some pictures when I get home.

The other thing is I can setup the return system to the transmission to shower the gear clusters from additional lubrication. This would require me to split cases and fabricate a shower rail system inside the transmission but it shouldn't be a big deal

 

subscribed to this.

the only time i HAVE broke a gear is when i didnt have torco rtf in it. i have not broke a gear with the rtf ever.

 

Sub'd.

I see someone already posted the prelude tranny cooler + pump thread.

 

So my transmission has wandered away(cleaning the house and the garage is being used as a stating area for furniture)

I went and got my tilton scavenge pump out of storage the other day, still works perfectly
It has 8an inlet and outlet fittings on it already and I feel this is a decent size to run, the transmission doesn't have a huge fluid volume so it wont take much to recycle it within the system. My concern also was that larger fitting diameter =larger diameter hose, so that's just a lot of fluid that isn't needed. Keeping the lines and everything small means it will have low pumping losses due to smaller fittings and short lines, also the cooler will be very small (need to see what I can dig up for a setrab unit) the filter I'll be getting off of eBay, the inline filter will have dual media, sizing of each media filter TBD.

I do know that the trans oil cooler will get a carbon fiber shroud and I'll be running a duct fan a local guy makes (imagine a shopvac on PCP)

Logistics
I know the fan for the trans oil cooler will be on a thermo switch, no need in planing extra load on the electrical system.
I still need to find a suitable thermostat unit to plumb inline so when the pump is on its not constantly fees fluid through the cooler... I know mocal makes a unit but not of many others.

All of these sensor based systems will have switched backups to prevent failurea, might even make a valved unit to bypass thee thermostat remotely (everything fails eventually lol)

I appreciate all of your replies links, and advice

Today I'll be taking pictures of all of the various components for my cooling systems, mostly oil and teams fluid, engine coolant cooling is still be looked at at this point as well