Intro: 2007 Cadillac DTS Transmission Fluid Change (all 7.5 Ish Quarts)
I decided to create this 'able since there are far too few instructions on Northstar engines (and because the dealership charges more than $300 just to drain the main pan's 4 qts). These engines seem to be a torturous machine that only the mildly insane attempt to work on themselves. Probably from the lack of free documentation and the enginuity that always provides a humbling/patience testing project that leaves you scarred mentally and physically. SO, now that I have that off my chest, this is one of the easiest maintenance tasks performed on the Northstar engine, so it is surprising that the dealership only does a half-complete job. With the right tools or something close enough, this task should take 2-4 hrs give or take for injuries, distractions, explaining to neighbors why you are using so many expletives and that they are directed at an inanimate object, but you are not off your meds, etc.
Consult your owner's manual (or the all knowing GOOGLE) for precise maintenance intervals and fluid levels for your vehicle. Mine is recommended flushed @ 100K miles. Before performing this task, make sure all tools and equipment used to lift the car and support it are in good working order. NEVER rely on a jack to hold your car off the ground for more time than it takes to put a jack stand under it. Be sure to find a proper load bearing point to place the jack stand. Don't want to create more work. If you have a set of ramps or a lift, then things get easier. I'll be using drive on ramps. Make sure your ramps/lift/jack stands are rated for the weight of your car.
Step 1: Gather Items Required for Quest
- Safety glasses or face shield
- Gloves (I have sensitive skin)
- Lifting devices
- Wheel chocks for the rear if you only lift the front
- Socket set/various tools (if you don't have a sort-of full set of tools, this probably isn't a task for you)
- Pan or something to catch fluid (at least 8qts)
- Cardboard to catch fluid that the aforementioned pan didn't catch
- Rags/paper towels to clean fluid that aforementioned cardboard didn't catch
- Jugs to recycle the fluid in
- AC/DELCO transmission fluid (8qts cheap on Amazon in 1Gal jug)
Step 2: Get the Car Off the Ground
During the lifting part of the process, it is a good idea to have a partner help you keep an eye on things.
Mine told me to stop before I ran off the edge of my drive on ramps. If you can't find anyone, then call/skype someone while performing the task so someone can witness your safety until finished.
If using jack stands, always put chocks behind the rear wheels (if not lifting all 4 tires off the ground) before lifting and always lift and secure one side of the car at a time. It is twice the work but a hundred times more safe.
After the car is on the ramps, secure the rear wheels by putting some sort of chocking device snugly behind it. Wood is my go to guy.
Step 3: Remove Primary Pan
The gasket for the pan is reusable, so don't fret about purchasing one (unless you have a damaged one, in which case you found/caused after you removed the pan. Insert expletives here...).
Loosen the pan bolts by HAND gradually with a 10mm ratchet (if I remember correctly). It doesn't matter where you start, but follow a criss cross pattern until one side is loose enough to drizzle a little bit out. The recommended side is the rear passengers to drizzle from, but it is unlikely that your gasket will separate from where you want it to (Insert pan and cardboard here). Try not to pry with anything to get the pan and gasket off. You risk damaging the gasket and pan. If necessary, tap with a rubber mallet gently on the sides to loosen the pan.
After it is finished drizzling, loosen the bolts the rest of the way on one corner to drain the fluid in the pan. Then remove the rest of the bolts.
Once pan is free, inspect the gasket and magnet for signs of fatalities. Some metal particulates are normal on the magnet and pan (or so I'm told). Take a picture of the shavings if you need to consult an expert at a local shop or store.
Step 4: Remove the Two Reusable Filters
Take a gander where the pan was and inspect the filters for debris. It is good to know, document.
Remove the two filters and clean gently with your brothers/sisters toothbrush and some cleaner that is safe on plastic if needed. Make sure all cleaners are rinsed off and the parts are left to dry before installing. Inspect for holes and tears. If damaged, replace. If not, set aside in a clean spot for later.
Clean the pan and magnet. It will look like brand new!
Step 5: Drain Secondary Pan
Remove the secondary pan drain bolt. It is located where the stream is coming from in the pictures. You will probably want to use the socket with the thinnest wall. It is a tight fit by the harness. The bolt was pretty hard to break loose.
Step 6: Remove Top Part of Air Box
To make it easier to access the transmission fluid cap, remove the top part of the air box completely by removing the torx screws, hoses, and pigtails (plugs). Then remove the cap.
Step 7: Improvised Tool (optional Step)
At this point, I rigged up my wet/dry vac to blow out the rest of the fluid. I did not see any more fluid come out, so this step may be unnecessary. If you feel like you need to do this, get a pair of panty hose with no holes in them. Make sure your wet/dry vac is super clean inside and the hose and filter are clean as well. Put a panty hose on both ends of your vacuum hose to collect any particles blowing out of the vacuum/hose. Remove the transmission fluid cap. Attach the hose on the "BLOW" side of your vacuum and put it on top of the fill cap opening. Turn the vacuum on and try to make a good seal on the hole. You may have to rig something up depending on your vacuum's accessories.
Step 8: Pan Re-assembly
At this point, assuming you haven't broken or lost anything (physically or mentally), you can begin putting everyhting on the pan side back together as it was in the reverse order (secondary drain pan bolt, filters, pan). Remember to tighten the bolts in the same manner by hand and criss cross, gradually, not all the way tight at once. You don't want to warp the pan. I was unable to find torque specs so I just gave it the 'ole gutentite by hand (the dealership can probably provide the torque specs).
Step 9: Filler Up
Now that you have the pan on, and no extra parts (hopefully), you can put some fluid in. I would start with just a quart at first to make sure there are no leaks. If there are no leaks, proceed to filling with 7 quarts. Screw the cap on.
Step 10: Air Box Re-assembly
Install the air box in the reverse order of removal. Now you are ready for a test drive!
Step 11: Test Drive
Once you have assembled everything, removed the car from its ramps or stands or whatever, make sure to remove wheel chocks. Go for a test drive, making sure to put the transmission in every gear to make sure the fluid is dispersed on all the gears.
Step 12: Final Fill
After your test drive, with the car running, check the transmision fluid level. If it is low, add some fluid until it is full to the indicator on the cap dipstick.
Step 13: Celebrate
Now that you are finished, go inside and celebrate knowing you have saved almost $300 by changing the fluid yourself!