Inline tranny filter

dangerous06

dangerous06

diesel tech
Joined
Mar 24, 2008
Messages
3,564
I put a 1249 Hydraulic filter inline before the Factory cooler about 3 years ago and my fluid has been clean ever since! Well I did a torture test on the set up let it run for 15 months and 30k of hard heavy hauling. Well today I pulled the filters and fluid. I Drained the pan first Still red with a slight burn to it but still clear. Next I pulled the in pan filter and it had very little dirt in it. I then pulled the spin on 1249 Napa filter and holy crap not only was it like a cup of liquid metal but it was heavy too! I have to say this filter set up works perfectly even when packed with crap. I have a pressure gauge because I was leery of the set up at first I thought as it clogged I would lose pressure but it never did! I just wanted to share a tranny saving idea that worked great!
 
So what is to be gained by this? The factory filter with normal changes has proven to be very effective in protecting the transmission.
 
Protects your transmission in the case of a torque converter failure by catching the debris before it can make it back to the transmission.

No need to drop the pan again for messy filter changes. Your OEM filter will only require changing every 100,000 miles or so.

The fluid in pan stays clean, protecting the transmission from debris.

The filter canister acts as a small transmission cooler

The bypass valve design allows fluid flow even if the filter plugs with debris.

Allows the addition of a transmission filter pressure gauge to monitor the condition of the filter.

Allows the addition of the transmission flush valve to make torque converter purging easier.

The spin on filter replacements are less expensive than the OEM style.
 
If your converter fails, you should probably rebuild your trans anyway because there is more than likely more damage than just that.

Prove the 100,000 mile changes. And you can get a double deep pan that adds more fluid for better cooling along with a drain plug.

The stock transmission filter keeps the fluid in the pan clean. If you have so much debris that its getting past the stock filter then you have bigger issues to worry about.

The external filter may provide 1* of cooling to the fluid.

So the bypass is another area that could possibly fail and block fluid flow and kill the transmission.

There is almost no one running a transmission pressure gauge so that's a moot point.

Last I checked its $30 for a filter and gasket. If you are breaking your budget over that, then you have bigger issues.
 
Last edited:
BgBlDodge said:
So it's another part that could fail or leak and isn't necessary. Got it. And last I checked, a gasket and filter were like $30 and it took me a whopping hour to swap it out and add new fluid so yeah. Not sure how it gets much easier.
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Like a lot of us i have more money into my tranny than i'd like to admit. I dont see why your being such a hater.. something like this is just added insurance for a good clean transmission. As far as another part that will fail or leak, well i guess that all depends on how stupid you are on the install. Tranny lines are pretty cut-n-dry, ones in, ones out. I'm not going to rush right out and do this but its good info i think.
 
I do run a pressure a gauge in the cab It has never even blinked 150 constant! As far as the stock filter doing a good job that's bull! Every pan I have ever dropped has had a coating of fine metal all over the inside! Sometimes a lot in the pan! Since the inline my pan and filter have been spotless as is the fluid. A high mileage or abused tranny even has a metal sheen to the fluid I just did 39k of ridiculous towing and the fluid was as clean as the day I put it in! Changed it because I know I got it hot a few times! IMO this mod is well worth doing as is the 2 micron fuel filter inline before the CP3!
 
dangerous06 said:
I do run a pressure a gauge in the cab It has never even blinked 150 constant! As far as the stock filter doing a good job that's bull! Every pan I have ever dropped has had a coating of fine metal all over the inside! Sometimes a lot in the pan! Since the inline my pan and filter have been spotless as is the fluid. A high mileage or abused tranny even has a metal sheen to the fluid I just did 39k of ridiculous towing and the fluid was as clean as the day I put it in! Changed it because I know I got it hot a few times! IMO this mod is well worth doing as is the 2 micron fuel filter inline before the CP3!
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Def agree on the pre cp3, my airdog 200 doesnt seem to do that great of a job. I had a contaminated rprv and injectors with foreign material. That is less than 200 miles on a set of purflow filters too.
 
What size lines are u feeding the filter with? I have a base, just need thee filter. Still running the stock collers?
 
I use -8 on my 03', im not sure if this would be needed on the 68 Dan.. It already has two filters. But i you did bigger lines with a bigger cooler then i probably would for the hell of it.
 
joelc79 said:
I use -8 on my 03', im not sure if this would be needed on the 68 Dan.. It already has two filters. But i you did bigger lines with a bigger cooler then i probably would for the hell of it.
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I was thinking for my 48re. Thanks
 
BgBlDodge said:
So what is to be gained by this? The factory filter with normal changes has proven to be very effective in protecting the transmission.
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I guess I should throw away my airdog because it already has a factory lift pump and factory fuel filter...
 
I look at things differently and don't prefer to over complicate. I've had a built transmission before so I'm well aware of the cost. This to me just seems completely unnecessary. Do what you want. I'll save my money and do regular changes at 20k mile intervals just like always and not worry about it. My built tranny is still going strong with nearly a 140k miles on it. Guess I just don't see the benefit of an additional filter when the factory one has proven quite effective.
 
apocalypse1812 said:
I guess I should throw away my airdog because it already has a factory lift pump and factory fuel filter...
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And I'll be more than happy to show you several people who have gone over 200k miles on stock filters and pumps and injectors....
 
the filter located in the oil pan is a suction filter in other words its a rock screen. your unable to keep a tight micron rating due to pump cavitation as restriction increases. all heavy duty transmission have a inline filter because its pressure feed and you can get a 20 micron filter. ive installed one on my excursion that's a 20 micron 98% absolute with a 5 psi bypass. I would suggest it.
 
I ran 1/2" lines. I cut the line going to the factory cooler put the spin on filter in line and ran the out back to the stock cooler as over kill I added two more coolers inline mounted under the bed than back to the pan My temp drop is about 15 degrees without the fans on and with them on I can keep the temps at 180 or below no matter what! Even when it's 110 outside!
 
Probably a stupid question but what oil pressure does the 48re run normally?
 
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