I bought a tru-cool #4739 for my trans. I didn't want to take off my other one that I bought (not the junk stock one) so I hooked them in series with T fittings. A transmission man told me that if one got clogged, then the other would still be working. I can't help but to think that my tru-cool is only getting half the flow or pressure in series and not cooling as much as it should. In parallel (without the T's) it would get the whole amount of flow and cool better. Maybe my thinking is going south on this one so I'm asking for opinions.

 

Series is out on the first one hooked to in on the second one.
Parallel would use Tees.

From what you have said you have them in parallel not series.

Yes in series you could get better cooling, but if one clogs, neither will work.
In parallel the one with the least resistance to flow is getting the most fluid.

 

In theory if they are in parallel with a tee, once the pressure equalizes, one cooler could get very little to no flow. The one with the least restriction (or easiest path) will get the most flow. I don't think they will ever be 50/50, but could be as good as 60/40. Time for a hydraulics engineer to chime in on this one.
Joe

 

I'm no engineer, but I understand the theory. To balance the flow through both you need to put a large oriface somewhere in each cooler to provide a little resistance to flow. Then the "easiest path" is somewhat balanced.

 

I also think it would help to equalize the flow if you had the bottom of the T fitting the input, and the sides uot to the coolers, then come in the sides of the T fitting, and out the bottom for the return to the tranny.

I am no hydralics expert, but thats is what I would do if I got another one.

Diesel Rod

 

So, what you guys are saying, I'm in parallel now. That transmission guy asked me how I had it hooked up, series or parallel. I said I don't know, I just went into one and connected the out hose to the other coolers in port. He said that was parallel, that series would be better in case one clogged. I'm confused, is it of your guys opinion that I should get rid of the second cooler and just use the tru-cool by its self? Or can you get more cooling out of two coolers if their hooked up right?

 

Your in series.

remember back in HS the two parrellel lines thing, where they are side by side. series is one after the other. I.E. a series of cars on the highway, one right after the other.

I would do it in series. I have never heard of a cooler clogging. but if I were to do it in parrellle it would be like I said before.

I think series would double you surface area, and parrellel would cut it in half.

Diesel Rod

 

Ok, now I'm confused. I would keep them inline with each other. Out of one and into the other, just like you would normally add one. Mine is: transmission > otw > factory ota > aftermarket ota > transmission. I would just add the other one between aftermarket ota > transmission. The likelyhood of them stopping up is no more than the factory ones getting blocked. Just my .02.
Joe

 

Dieselrod, good memory about the school example. I can't even remember what school I went to.

Yes, SERIES.
Into the first one, fluid continues flowing and cooling, through line and into the next cooler, cools it down even more, the back to the tranny.

If you have an external filter (recommended) it lessens the extremely small chance of a clog. The external filter even adds a slight amount of cooling itself.
Diesel Site sells them with a filter minder and flush valve. ($109. I think)

May as well replace the stock filter (crummy) and fluid too.

The Tru-Cool is my next purchase.

 

Lots of good advice so I did some testing. With the T's on and feeding both coolers at the same time, I made a back roads run of about 7-8 miles. Running it hard I got up to 180 degrees. I then removed the T's and feed the tru-cool cooler first, then the second cooler (hayden), I made the same run. It only got up to 150 degrees. I think the tru-cooler has more resistence and most of the flow was going thru the hayden on the first run (path of least resistence). Thanks for your help!

 

Excellent test. Seems like your test has answered your question for you and for us.
Joe

 

guys don't be sayin stuff about back in school it will make some of us feel really old and for some that is a touchy subject! LOL