In-line Transmission Filter With Bypass Valve

[pwilcox]

I have a THM 350C AUTOMATIC TRANSMISSION that I am rebuilding. ISN'T IT A GOOD IDEA TO INSTALL AN IN-LINE TRANSMISSION FILTER WITH A BYPASS VALVE? I want to install it in the COOLER LINE between the TORQUE CONVERTER and LUBE CIRCUIT to keep any particles out of the lube circuit.

If yes, then which one should I buy? I can't use a SPIN ON FILTER because of limited space unless it 's a MINI.

[ivymike1031]

didn't like GregL's answer, eh? Welcome to AF.com...

Doesn't your th350 have a filter built in? Are you adding additional filtration, or replacing the pick-up filter?

[pwilcox]

As far as BUILT IN FILTERS go, my THM 350C has PRESSURE REGULATOR AND GOVERNOR SCREENS in addition to the normal filter. These DO NOT protect the LUBE CIRCUIT which is supplied by fluid returning from the cooler. My TORQUE CONVERTER sends its fluid directly to the cooler.

So I 'm wondering if it's a good idea to add an IN LINE FILTER WITH A BYPASS in the cooler line.

If yes then is there one that is better than the rest?

[ivymike1031]

so the fluid flow goes like this (?):

1) pick up from sump (filter)
2) pump
3) torque converter
4) cooler
5) lube circuit
6) the rest of the tranny

??

[pwilcox]

From my understanding of the THM 350C the fluid flow goes like this:

1-fluid pickup at filter
2-pump and pressure regulator
3-after the pressure regulator it splits between
a) torque converter
b) valves, accumulators, governor,
modulator and pistons

4- the fluid that goes to the torque converter goes directly to the cooler
and then to the lube circuit.

[ivymike1031]

so your concern is that particles will enter the fluid after the filter and then pass through the lube circuit?

[pwilcox]

Yes---specifically particles from a defective torque converter will apparently go to the lube circuit if there is no in-line filter.

So isn't installing an IN -LINE FILTER WITH A BYPASS in the cooler line a good idea?

If yes, then is there a brand that's better than the rest?

[ivymike1031]

dunno... I guess that would remove the particles... I'm wondering how often a torque converter will fail in a manner that produces excessive particles. I guess the lockup clutch could leave chunks in the fluid, if the tranny is so-equipped. It seems that most people go a really really long time w/o a tranny failure, and when they do have a tranny failure, the TC is replaced simply because it's full of crud from the broken tranny.

There are people out there who use filters between the TC and the fluid, but they don't seem to be all that common. This guy ( http://www.se-r.net/transaxle_clutch/auto_lsd_info.html ) mentions that he is looking for one for his nissan, you might see if you can contact him to see what he found.

Alternatively, I found these other sources of info that may be useful to you:

http://www.humvee.net/hid/rungear/trancase.html "The inline trans filter I used was from Summit Racing Equipment, Phone: l-330-630-3030. You can buy it as a complete kit, #PRM l0677. It comes with a temp gauge also"

I took the liberty of tracking that one down (there was an error in the part number) - follow this link: http://store.summitracing.com/partdetail.asp?part=23047


http://www.dakotart.com/faqarticles/...tall/page7.htm " I recommend installing an inline tranny filter just incase there was some debris that got by during the installation. I installed mine on my passenger side fender. I plummed it the following way. Tranny - Radiator - In line filter - Aux cooler - Tranny. You should install the in line filter before the radiator but I did not since it was more convienent to install the filter after the radiator and before the aux cooler. "

[pwilcox]

Appreciate your effort IVYMIKE1031!!!!

[Freddie's Buick]

I can't add any suggestions to this thread. You guys know much more about this then I do. But I have a question about my THM-350C and perhaps you guys can help. Many thanks!

My THM-350C is an ECM controlled 'lock-up' type and it works great along with my '81 'G' body classic, (gotta love it)! But I have a whole lot of mods that will require me to get rid of the computer.

What would happen to the trainy if I get rid of the computer?
I know how to put a switch on it to lock up without the need of the ECM.

But when should I use the lock up? Can I run it without having to use the lock up feature and not do any harm? :bandit:

Your answers are very much appreciated! :smoka: