How-To: Remote Spin-On Transmission Filter Kit.

FL335i · March 30, 2016

Has anyone installed a spin-on filter kit for the trans on the K2's yet? I want to install one. Going to be my next mod. Go along with my coolant filter kit and 1500 HD Badging. JK on the badging. Looking for tips of mounting location, fittings etc... Looks like I might be going blind on this mod too.

Coolant System Filter How To:

Update 04/09/2015

Ok, the remote spin-on trans filter kit went on this morning at 41,843 miles.

Parts and costs:

-Derale base kit. Part # 13005. $32.92

-Napa Gold Hydraulic Filter. Part # 1269. $13.00

-Napa Pro Select Filter. Part # 21515. $3.18

-3/8" Transmission Hose. I bought 6', used 1'. $3.56 for 1'

-3/8" SST Hose Clamps from HD. Had them already, they're like $1/ea. Figure $4 for clamps.

-1qt of Dexron VI. $6.41

Grand Total cost of $63.07

Let's talk flow direction of the trans fluid. There was a lot of threads on the internet regarding which port on the trans is the output and which is the return, which way it flows through the radiator and external cooler. I can say for certain, that the flow direction goes into the external trans cooler (Condenser top portion) on the passenger side, then goes into the top of the radiator and comes out of the bottom of the radiator and back to the transmission. I actually had the hoses on the filter base backwards at first. With everything hooked up I had my wife start the truck while I was under it to visually verify the trans fluid was flowing correct into the filter base. Good thing I did, b/c based on the internet theories it was backwards. I swapped the hoses on the base and re-verified with the engine running for a few seconds. Flow path is as follows: Transmission -> Filter base -> External trans cooler (condenser) inlet on the passenger side -> small metal hose that goes from the external cooler into the top of the radiator (driver side) -> out the bottom of the radiator (driver side) -> back to trans. I cut the section of factory rubber hose that goes up toward the passenger side (ext cooler/condenser). I did this out of pure fitment and install. I could care less if the filter was before or after the radiator/cooler. Does not make a difference. With my setup, I was able to cut the factory rubber hose and hook it directly to the filter base. Eliminating another splice and more clamps. I wanted to keep the factory metal lines in place also. Trying to keep the chances of a leak and or issues as low as possible. The 21515 (PH8A) filter I have in the pics is a monster. 1qt filter. It hangs down quite a bit below the frame, but it does clear the skid plate. However I would not consider it a prime location for rock crawling and smashing through the woods. but I wanted to make sure I could run the full size PH8A filters and still install the skid plate. Mission accomplished. I'm only running this monster filter for about 2 weeks and then I'm changing to the small compact 1269 hydraulic filter. I wanted to run the cheap oil filter to do some initial cleanup before I put a $13 hydraulic filter on there that's rated at 10 micron. Side note, the wix filter for the factory allison transmissions is rated at 15 micron. I'm happy with how the install went. I will snap some updated pics in few weeks when I change out to the 1269 filter. That filter should barely hang below the frame. It's half the height of the 21515. Hope this helps guys. I spent 80% of my time just laying on my back figuring out where I was going to mount the base.

Another option could be to use a Magnefine filter in the factory rubber hose sections. I could of installed that thing in 5 minutes. I have a magnefine on my '89 K5 P/S system.

Another side note. I'm just shy of 42k miles. the ATF if factory fill and when cutting the line and all what I caught my oil drain pan container was darker than expected. Yes I have towed, not a lot. Lots of Hwy driving too. But the fluid compare to the new fluid I put in was unreal. Color was very dark. It smells bad compare to the new quart of fluid. My point is I would say I would definitely be due for a service at 50k. I may actually leave the monster cheap oil filter on there and just do a full trans pan service at 45k. Along with adding a PML low profile aluminum pan so I have a drain plug. Put the 1269 filter on at that service.

Edited April 9, 2016 by txab

FL335i · April 5, 2016

As for the trains kit, I posted in someone else's old thread about the trans cooler. I found two GM diagrams of the oil cooler and trans cooler. So I posted those to help out and heck, helped me b/c I did not understand the arrangement of piping and parts to be honest until I found those diagrams and looked it this past weekend. I ended up buying a Derale filter base from summit racing for $32 shipped. Starting with that. Going to run a NAPA 1269 hydraulic 10 micron filter. I'm going to cut one of the trans lines at the rubber section and barb into with some 3/8" hose. I need to figure out two things.. 1- where exactly to I want to mount the filter/base. 2- if I'm putting the filter inline before the radiator/cooler or after. I'm leaning toward the later. That would mean the fluid comes out of the trans, go to the radiator, to the condenser (ext cooler) and then to the filter and back to the slush box. I'm going to remove the front skid plates and see what room I have and pick a spot on the frame. I've got this kit about 90% built in my head. It's not rocket science. But my truck has 42k and the fluid is not exactly looking new anymore. The last detail I'm thinking is going to be putting a magnet on the dome end of the filter, or side... Something. I just installed a Magnefine p/s filter on my '89 K5 and like the idea of a filter and magnet. Don't worry, I'll do a write up of this kit too.

Edited April 8, 2016 by txab

kd2dwj · April 5, 2016

There's plenty of room under here on the frame, I'm looking at the tranny right now.

Honestly I'd put the filter in before it goes to the tranny cooler, the fluid will be at it's thinnest state when it's hottest and the filter should allow the fluid to pass quickly while trapping contaminants.

Idk how I feel about barbs for this, we are talking a lot of pressure here, maybe some stainless AN lines, I wouldn't mind even making new lines from the tranny all the way to the cooler to add the filter just for the piece of mind.

FL335i · April 5, 2016

^ It's not much pressure. IIRC 30psi. The key is good hose and clamps. I'm going to do my HW on the hose. no autozone stuff.

Edited April 5, 2016 by FL335i

txab · April 9, 2016

Good write-up

FL335i · April 10, 2016

Update. I've driven the truck around today to run some errands. Warmed it up and came home and checked the trans level. Touch low, but 1qt is what this kit added. I'm about 1/2qt low right now even after adding a full 1qt, probably what I lost cutting lines and visually checking flow. Just a short 20 miles around town proved to clean the fluid up a bit. the fluid is not as dark as it was yesterday. I have some sample kits coming from Blackstone Labs. I'm going to have my engine oil checked out at my next oil change, probably run it down to 15% left on the OLM. I'm going to pull a sample of the ATF after a week of running the 10 micron filter.

Edited April 10, 2016 by FL335i

Eddie 70 · December 4, 2016

I like this idea. Especially since I am seeing that you have to loosen the exhaust at the manifolds to get the pan to clear the crossover pipes. I am at 75K on mine and think this would be added insurance.

How is this working for you after a few months. Everything still nice and clean? Any issues? Leaks? Anything you would have done different?

Anyone else done this?

Edited December 4, 2016 by Eddie 70

Bobaloo22 · December 4, 2016

Great idea! I also am very interested in this mod.

Thanks,

Bob

FL335i · December 5, 2016

This mod is working out great. NO leaks. Shifting is great. I'm at 57k and the fluid is still pretty good looking. However I'm off for 2 weeks around Christmas so I'm dropping the pan and replacing the filter with a AC Delco. I also got two gallons of AC Delco Dex VI fluid on Amazon cheaper than I could buy stuff locally. So in two weeks I should be on 60k's doorstep. Doing the pan filter and external filter + fluid.

Eddie 70 · December 6, 2016

I haven't bought any fluid yet but need to in order to get this done over the holidays. I see there are two versions of AC Delco Dexron VI in gallon jugs on Amazon. Which did you buy? Any reason for one over the other?

FL335i · December 6, 2016

I bought the part # that ends in 5 IIRC, not the 930, but 935. I don't think there is a difference..... One is sold by GM, the other AC Delco.

sdeeter19555 · January 3, 2017

Has anyone considered a bypass filter instead of a full flow filter...better filtration, less chance of restricting flow?

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FL335i · January 13, 2017

I doubt the filter gets that plugged up.... I change it at every 3rd oil change. I cut mine open after 3 oil changes and it didn't have anything in it that was visible with the naked eye.... looked like a brand new filter with ATF in it. Plus... Just looked it up, the 1269 filter has a 8psi bypass valve built in. Just like an oil filter bypass. So if the filter is clogged, the bypass opens and you still get flow.

Edited January 13, 2017 by FL335i

FL335i · July 31, 2017

68,500 mile update. Running great. Fluid is clean. IIRC, I'm on the 2nd filter. I think I'm going to be doing a filter every 3rd oil change. Which is about 14months for me.