I got a aftermarket automatic transmission cooler for my Ford C4. Is it best to install it before the lines that go to the radiator or after the radiator? Or is it best to just bypass the radiator?

Clayton

 

Its best to install the aftermarket cooler AFTER the fluid has passed through the stock cooler. The stock cooler is more efficent in removing heat from the transmission fluid as it is a liquid to liquid transfer, the remaining heat will be reduced further by the aftermarket cooler which is a liquid to air transfer.

 

i put mine before so the fluid warms up quicker in the winter

 

I guess the goal is to keep the transmission at the optimal temprature. But what is that temprature? Same as the engine coolant 160-195? If the trans is too hot it doesn't perform well and it may get dammaged. If it is too cold it does not proform right either. Perhaps installing it before the rad is better. That way the temp will be just under the engine coolant temp and allow the trans to cool better under hard use. Also the trans temp should remain consistant.

Clayton

Clayton

 

youre thinking correctly but wrong at the same time. Recommended transmission temps vary based on a few things, 1. the purpose and useage the transmission built for and sees 2. where the temp sensor is located 3. the size of the cooler(s).

Generally speaking, most transmission shops/builders will tell you temps should be about the same as the engine coolant temps, +/- 20 Degrees based on ambiant temps as well load. If youre getting into high-end builds involving high stall converters and such, youre temps are expected to be a little higher and then of course its a matter of finding the correct size cooler to maintain that temp.

Any temp between 140* and 210* is considered "safe", however if I personally saw a trans running 210* all the time, you better believe I would getting a larger cooler.

Now if you think putting the cooler in front of the original cooler is going to make the temps lower than if it was after the original cooler, youre wrong. You might as well not even install the aftermarket cooler at that point, because basically like I stated earlier, the stock cooler is more efficent and will take most of the "shock" (heat) out of the fluid, thus helping the aftermarket cooler work more efficiently.
By installing it before the original cooler, the aftermarket cooler will not do an adequate job of removing heat before it reaches the original cooler and will thus make it seem like its not even there, or even if it does happen to remove enough heat to get the trans temp lower than the engine coolant temp, the original cooler will put heat BACK into the trans fluid, so again, making the aftermarket cooler basically non-existant.

Im surprised there are no instructions in the kit telling you all this, every trans cooler I have ever installed says to tap into the return line on the radiator which would basically eliminate any question on where to put the cooler in this series.

FWIW, here is my B&M 28000 unit mounted, waiting for new braided steel lines:

 

NJTy180,

Thanks for the info. I think your right. I will mount mine after the rad. My cooler looks simular to yours but doesn't use compression fittings on it.

Clayton

 

What if you dont have a rad with the trany cooler built in ? such as in an older truck that originally had a man trany and you are using an external cooler only ? Best location ? and should it have it's own electric cooling fan ?

 

No problem, good luck with the install.

In terms of physical location, putting it in front of the radiator with as few obstructions as possible would be best. Youre not going to get the "best" cooling out of it and naturally the bigger the cooler, the better. Ones with pusher-fans on them work very well, but of course you pay for it in the wallet. If your doing lots of towing or "off roading" where youre putting a lot of stress on the transmission but not going all that fast, one with a fan would be ideal. Of course you could also pick up a used late model radiator (and probably the lines too) from a junkyard and gain some cooling advantage that way.

 

I have seen many transmissions that the owners bypassed the radiator cooler and installed an auxiliary cooler and all metal parts inside the trans covered with rust. This is from short driving trips where the trans never gets hot and condensation collected. Running thru the radiator cooler will heat the trans faster, then add your auxiliary cooler on the return line. Stay away from rubber tubing, hard pipe the whole system to prevent line, trans failure. Run the cooler in the airstream away from the radiator, you don't help the radiator by adding hot cooler air to it. I installed an extruded aluminum cooler, 30" long by 3" diameter that has 20 fins full length ( 337.5 sq/in fin area plus 138 sq /in ) outside between fins. Total area of 475.5 sq / in or 3.30 sq / ft of area. The cooler has fins inside for the oil also. It's mounted across the lower frame rails in front in the airstream. A remote spin-on filter on the return line will keep the oil clean in addition to that coarse screen in the trans plus adding a magnet inside the pan and spin-on filter. Private email me i'll send photos as to post on this form is a PITA.

Carl....=o&o>....

 

Can you expand on this? Point to references or discussion on it? I've been searching for what is the minimum operating temperature of transmission fluid. I see many references and discussion on what is too hot, but nothing on what is too cold.

I recently added a transmission cooler to my car but bypassed the stock cooler. Many people assert that I should keep the stock cooler in series, but other say it's not a concern in Texas. We rarely see 30*F in the winter. However, I'm still searching for the temperature that is considered "too cold".

Thanks.

 

Without the radiator trans cooler the transmission will have slower warm ups that will cause alot of condensation on short trips, internal metal rust as well thicker oil viscosity due to below normal operating temperatures in your 30+ degree enviroment. Too cold can be as bad as too hot.
.....=o&o>.....

 

Right, but what is "too cold"? Does anyone have some numbers to define too cold?

 

well again I will state that I am no transmission expert, but just through some searching, I have found the following information about transmission temperature gauges:

TCI 150° to 300° F

Autometer 140° to 280°

Stewart Warner 140° to 320°

Given that these are transmission specific analog gauges (especially the TCI gauge), I would assume that range is what is considered a maximum and minimum for trans temps.

Now knowing that temps that exceed 210° for long periods of time will shorten transmission life (may very slightly depending on the trans) although the gauge goes higher, leads me to believe that inversely temps below maybe 160° may be harmful to transmission parts, however I have no proof.

Although there are some transmission gauges that read from 100° up, its my opinion that anything below 140* is not within normal operating range and anything below 100* will most likely be causing some sort of damage.

I know its not real solid evidence, but I know if it was me, I would try and keep my temps between 160* and 200*.

Hope that helps.

 

I was searching online for transmission cooler bypass valves. I saw one a few days ago but didn't pay much attention to it. Now, I was thinking of installing one. In my search, I came across an inline thermostat by Derale that will turn on a fan at 180*F and off at 170*F.

Given that, and the other information in this thread, I'm gonna say my 120*-140*F transmission fluid temperature is on the cold side and I need a cooler bypass valve with a thermostat to warm it up a bit.

 

I had a conversation today with my transmission friend (45 plus years in business) who did custom hand fitted and modification work (he invented the Lenco transmission besides running Top Fuel). He wanted to see transmissions lower temp at 160 to 180 degrees for long oil and seal life. You can pull a hill and get over 240-260 plus but the average temp will determine oil, seal and trans life. Also run thru the radiator first, aux cooler then a spin on filter before returning to trans. Also add magnets in the pan and spin-on filter. The spin-on filter will also act as a water trap.
.....=o&o>.....