[DurmaxPowderHound]

Since buying my truck, a good chunk of the miles I put on it have been hauling and towing, and I usually don't leave my locale without some kind of load. My truck's mileage is approaching the severe duty recommendation for transmission service. I'm curious if it's possible to do a DIY service on the transmission that's comparable to what a mechanic can do.

 

[alberta minimax]

You can but the procedure is a bit involved as there is no dipstick.
You will need a hoist or other lift and all the usual pans tools etc. As well as an infrared temp gun.
Drain, replace filter per normal.
There is a fill plug up on the side of the transmission that is difficult to access without a hoist or other lift.
Fill transmission with similar amount of Dextron 6 ATF that you drained.
Warm up the transmission to 40-45 C. This opens the proper circuits within the transmission. Continue to top up transmission until fluid just starts to appear to drip out of the level plug.
Reinstall both plugs and you should be good to go.
It is imperative that the transmission is up to temperature during this procedure.

 

[Duken4evr]

Seems the trans temp readout in the DIC would be a handy way to monitor trans temp while filling also?

 

[mmiikkee]

You can but the procedure is a bit involved as there is no dipstick.
You will need a hoist or other lift and all the usual pans tools etc. As well as an infrared temp gun.
Drain, replace filter per normal.
There is a fill plug up on the side of the transmission that is difficult to access without a hoist or other lift.
Fill transmission with similar amount of Dextron 6 ATF that you drained.
Warm up the transmission to 40-45 C. This opens the proper circuits within the transmission. Continue to top up transmission until fluid just starts to appear to drip out of the level plug.
Reinstall both plugs and you should be good to go.
It is imperative that the transmission is up to temperature during this procedure.

You don't need a hoist or lift. You can do it with the truck on the ground but axle stands or a lift will make it easier.
The fill plug is easy to access without a lift. You will need a oil jug with a pump or something similar to get the oil back in. Mine cost less than $15.
After dropping the pan, changing the filter and putting the pan back on put in 6L Dexron VI. You will not capture all of the fluid and if you only put in what you got out of it you will under fill the transmission by a lot. I got 4.5L out in a container and spilled a bunch elsewhere. I filled with 6L and about 125ml dripped out when checking the level.
Fluid level is to be checked with a transmission temp between 30 and 50 degrees C. There is a decal on the tranny explaining it. Tranny temp is displayed on one of the info screens on the dash. Truck needs to be level and running.
There are a few guides online that outline the procedure very well. It is easy to do and well worth the time. The dealer will hose you for parts and labor.
Explore a few of the options listed online for draining out some of the oil before you drop the pan. It will be much less messy!

 

[Burgess159]

Yea, like Mike said, you don’t need a hoist. I did mine. If you loosen the pan bolts and remove all but 2 on the front of the trans, that will obviously make the pan want to fall down towards the rear. Have a big catch pan there and you’ll get most of it. Then pull the remaining bolts and gently lower the pan and dump the remaining contents.

Clean the pan, replace filter (if you want). The gasket is reusable if you do not have a new one. Rebolt it all. Next, remove what looks like it should be a drain plug (it’s not, it’s the full check plug). On the drivers side on top of the trans is a full hole that has a black plastic plug in it. Remove that. Now, like Mike said, you need a fluid transfer pump. Stick one end of hose in trans and other in your new fluid container and start pumping. Should take around 6 qts. Also, make sure you are on LEVEL ground. Once you have 6 qts in, or when fluid starts flowing out of the full check hole, you’re done. Replace plugs. Go drive around and get the trans up to at least 123 degrees (it’s that or 121) which is operating temp. Once there go back and pull that full check plug with a pan under it and ready to catch any fluid. Fluid expands when warm so you should have some come out. Once it stops, you’re good. Replace bolt and go on with your life

 

[Duken4evr]

Here is a photo showing the inside of the pan and the tube for the level check plug that looks like (but is not) a drain plug on the bottom of the pan.

Another way to fill it instead of pumping it from below might be to use a trans funnel connected to a length of tube into the fill hole. Did that trick on my wife's car and it worked well. Dunno if we have that kind of access from above on our trucks though. If so, that is a good way to go.

 

[Dmax Dan]

Does anyone know the Torque specs for the trans pan bolts?

 

[EKarlW]

The 6l45/50/80/90 (6Lxx) range is pretty much the same in respect to pan bolts and this site says the pan bolt torque is 9Nm/80FT-LB (which seems a little high) for the 6l80/90 - but this was pretty much a quick search so more hunting may be needed

 

[Duken4evr]

Trans pan bolt torque spec is 6-8 ft. pounds, not 80. The zero matters ?

Just got done installing a PML deep pan, honestly probably next to unnecessary, but what I can I say, I wanted a drain plug and it looks cool AF. Some observations:

A T-handle 10mm is the ticket for easily removing the pan bolts. If you do not know the joys of having a T-Handle set, go get them, they are awesome.

To remove the black plug on the trans fill hole, push up on the top plunger thingie, then push up on it with a flat blade screwdriver, it comes out pretty easy. If you have compressed air, it is a good idea to blow out that area to make sure dirt does not drop in when you remove the plug.

I decided to preemptively suck the oil out 1st before removing the pan, attached is a photo of my pan right after I pulled out all the oil I could using a Penzoil hand pump I bought at Walmart. As you can see, sucking it out first got most of the oil. Hand pumps work great for getting the oil in and out. I planned to replace the pan with the PML and wanted to avoid a "Red Sea scenario" when removing the pan. Taking a little time up front sucking the oil out first before dropping the pan was so worth it! Trans oil is remarkably drippy, but sucking the oil out of the pan 1st avoids the aforementioned "red sea" scenario. Having a good absorbent old towel on hand spread out under the work area is nice regardless.

A cool feature the random Penzoil hand pump I got is the hoses are quick detach. Push in on the quick connect white collars and the hoses release, so you can swap them on the pump. Make sure whatever pump you get has this feature.

My truck has 40K miles on it, as you can see in the photos, the fluid looked really good actually, not a lot of iron sludge on the magnet either. I figure it is good to stay ahead of it though. The filter looked good too, it was a waste of $30 changing that I suppose. Honestly, removing the pan is a bit of a waste of time too. You would do quite well to simply suck the oil out with a pump, measure it (I got about 5.5 quarts - the jug shown in the photo is a 5 quart I keep around for measuring used oil) and refill with what you took out. Drive for awhile and repeat if you really wanna be thorough to dilute the old trapped oil in the torque converter you won't get by draining the pan, and call it a day and never remove the pan. I would skip pan removal if I had a V6 as they have the crossover exhaust in the way of the pan. From my experience, if you change the oil early, this job really does not need to be too difficult and removing the pan is nice to do, but not absolutely necessary.

Final observation - the PML pan I got came with a cool little "dipstick" for measuring the trans level while cold. Attached is a photo of that - it is nice, but not absolutely needed, to have the dipstick when refilling, as you use the check bolt on the pan once the fluid is up to temp.

Description of photos:

1- Oil pump with quick connect hoses (a real sweet feature). It did a good efficient job of moving the fluid.
2 - Suction hose in trans fill port on passenger side of trans.
3 - Removing stock pan with t-handle. Torque for the pan bolts is 6-8 ft. pounds or "lightly snug" which you will see when removing them. No need to test your grip strength here when installing.
4 - Removed pan, note the suction hose to the right of the filter. A big old towel spread on the floor his nice to have here, as it will drip for awhile, unless you have a super huge drain pan.
5- 5 Quart jug filled to brim. I think I got 5.5 quarts with pan removal and filter draining. Probably will see about 5.25 quarts if just sucking it out.
6 - Stock pan as it came off the trans showing the oil left after I sucked it out the best I could.
7 - The PML pan that went on. Note the cool white plastic mini dipstick where I marked the cold level before draining. It is sitting on the middle sheet of paper.
8 - Magnet in pan after wiping showing iron sludge residue. This is not bad. My kid's Kia which has 135K miles and has been quite neglected had a lot more...
9 - Detail of trans filter inlet, looks pretty darn clean to me.
10 - My new bottle holding setup. Was paranoid about kicking the bottles over. Had this Styrofoam box laying around so it was recruited to the cause.

 

[Dmax Dan]

@Duken4evr thank you for the solid write up and pics. I picked up two of the pumps you recommended previously, just by shear chance when planning out all of my drivetrain fluid changes.

On a different note, the method I saw in this video

looks incredibly easy and solves the torque converter issue. Prior to doing the exchange, he has a video draining the pan and changing the filter then refill. Obviously, I would have to drop some extra money on the dipstick but having not looked, does anyone know where our transmission return line is? It is a little more crammed under the hood compared to the 1500s. Thoughts?

 

[Duken4evr]

We have the exact same setup with the return line. Remove the black plastic skirt thing, which has four 14mm bolts and is easy to take off. The return line is on the bottom of the radiator, on the driver's side. We have the same quick connect shown in the video, a 3/4" ID hose fits snugly over the bolt as shown in my pic. Use a good pick like he did in the video, there is not a lot of tension involved on the clip, but you don't want to get it in your eyeball or have it fly off either just remove it carefully and orient it correctly putting it back on.

I decided the next day to do the return line trick and of course by then the system was cold. It initially flowed a bit (as shown in the photo) then stopped and I did not get much fluid (yes, the pan was full) only a slight drip. I think I blew it by waiting until the next day and suspect there is a thermostat involved, so it does not send fluid until it reaches a certain temp. Anyway, learn from my mistake and do it all while everything is warm. I gave up as I figured if I warmed it up again, the oil would all mix and defeat the purpose. If I am wrong about why I did not see fluid please enlighten me.

I gave up as the old fluid was barely dirty and I apparently screwed up by not doing it the day before when the system was warm. I plan to drive it for awhile and then suck out a measured amount of fluid later, and add back the same amount later to address diluting the old trapped fluid in the system with new fluid. I have way more oil than I need, will probably suck out 5 quarts to use it all, and it will basically be overkill, which is SOP in my world

Bonus factoid - while under there, I noticed we do indeed have a drain cock on the bottom of the radiator on the passenger side. Woo hoo! I did not think we had one of those.

 

[Dmax Dan]

Perfect, just the info I needed, thanks again!

 

[Dmax Dan]

One last thing, I see your're using the HP LV, do you notice any difference in the trans? I was watching some videos where GM specifically states Dexron VI for 6spd, HP for 8spd, and HP LV for 10spd but if the 8 has a shudder then use HP LV. I am going with what I believe to be a lower viscosity than Dexron VI, hoping to have cooler tranny temps while towing, so I was just curious.

 

[Duken4evr]

Have not had a chance to drive it yet. PML sent me the wrong check plug, so it has a small rag blocking the hole. They apologized and are rushing me the correct one, should have it tomorrow, am very interested to see how the HP LV fluid works. It is supposed to be backwards compatible and no be hydroscopic.

I have not had any trans issues at all to date, it works really well with the tune installed. Will report back after I drive it with the fancy fluid. Got a smoking deal on it on Amazon by the way, $45 for a box of 6 and is commonly $10 or more a bottle everywhere else.

Here is a pic of the pan installed. It should act as a big heat sink, and it holds another 2 quarts of fluid. It is deeper but does not hang down below the cross member. Do not do any off roading more strenuous than forest service roads and am not too worried about clearance.

 

[Dmax Dan]

I've been weighing on a PML pan for the last year or so, please update with your results. I usually see temps above 230 in the summer, while towing my boat. It has made me more and more anxious, especially coming up on the 90K mark. I just can't afford to have the dealer do it again, since they charged me $1,000 bucks last time. Albeit, I was towing 800 miles from home and the rear wheel seal started leaking, so I just had them do all of the drivetrain fluids while it was there.

 

[Duken4evr]

Have you removed the plastic panels which are located precisely at the bottom of the radiator, right where the trans cooling lines plumb into it? I think those stupid panels really raise the trans temp, and am thinking removing the panels will make more difference than the PML pan. Just taking those off drops the temp 15F from what I can tell. Have not had any issues in winter without them either.

We will see this summer, but I think with the PML pan and the panels gone, I will have to really be working it hard to have the trans exceed 200F. Stock it would go over 200F just driving around on a warm day. Stock with no panels it might go into the 190s as opposed to 210 or so under the same conditions with them in.

Here is a pic of what I am talking about. They can be removed with the grille in place, just use a long needle nose pliers to squeeze the clips to get them to release, and then push them down and out past the soft rubber gasket at the bottom and straight into the recycle bin with the air dam

 

[Dmax Dan]

I am doing this tomorrow, thank you for all of the insight.

 

[Duken4evr]

Got the proper check plug in and installed it, finished filling the trans cold to just shy of the level it read before on the PML dipstick when I started. Warmed it up 115F, pulled the plug and a little fluid came out, maybe about 8 ounces. Seems the mini dipstick is pretty accurate. Will check it again one final time tomorrow when it is cold to see if it is close to the original mark.

Took it for a 52 mile mostly highway drive, the new blue label Mobil 1 fluid works fantastic. Probably some psychological stuff going on as I spent a decent amount of time in this endeavor under my truck getting trans fluid dripped on me and the trans worked great before, but it I believe it feels more fully "refined" now, shifts are quick and smooth on the throttle and nearly imperceptible when taking it easy.

I can definitively say it works better in Tow/Haul mode, feeling a lot less rough and dump truck like as it downshifts with the exhaust brake on going down a grade. It is still firmer in tow/haul, but the harsh aspect of it is completely gone and I will use that feature more now. Quite pleased with all this. The combo of the trans tune and the blue label Mobil 1 fluid is pretty awesome - it is so smooth!

It was 55 degrees out during my drive, so it was cool. Max trans temp at the end was 159F, while I would expect to see mid 180s with everything stock. Time will tell on that, but it seems to run up to 25-30F cooler from my little run. The thick aluminum pan definitely absorbs and transmits a lot of heat, it felt nice and warm when I was under there checking for leaks. I do think removing the panels behind the grille I referenced earlier, and the beefy transmission pan working together do drop the trans temp by about 25-30F.

PML says the pan holds another 1.5 to 2 quarts more than stock. I meant to measure that for myself but didn't. I think the pan hold more like 2.5 to 3 quarts more. It took about 9.25 quarts altogether to do the job. Some of that was waste/lost for sure. Let's call it 9 quarts, and around 6, maybe 6.25 with my aborted return line exercise, came out, for a roughly +3 quart capacity increase.

Attached for reference are the spec sheets for Dexron VI and the HP fluid. HP is slightly lower viscosity and has slightly better viscosity index and flash point numbers. I believe the fully synthetic HP is basically a slightly better version of Dex 6, and it works just fine in the 6L50, much like Amsoil, which is also not Dex 6 approved, works just fine - great, actually. Don't get hung up on HP not being Dex 6. It is better

 

[Jabhill31]

@Duken4evr just followed your writeup on my 2016 Colorado. It was real easy. Took me an hour or so with a few smoke breaks and some cleanup time. Mine is at 64k mostly unloaded highway miles, and hadn't been done yet. Fluid was a bit dark and magnet was black. But it didn't smell burnt at all.
Just to compare cost, I contacted my local Chevy dealer to see how much they wanted. Over $450 with 2.5 hours of labor included.
Thanks again. You made it too easy.

Josh

 

[Duken4evr]

Sweet! Glad my post was a help.

It as been awhile since posting this, the LV HP fluid continues to work great, and I remain super pleased with the lower temps. It definitely is running substantially cooler than stock, peaking at around 105F over ambient air temps, which is way better than before.

FYI - measured my stock pan's capacity and COFans board member 16WhiteColly measured his yet to be installed PML pan, we compared notes and determined that the PML pan holds 2.5 quarts more than stock. The PML holds 7.25 quarts to the check plug hole, the stock pan 4.75.