What Would Ya'll do to Equip a Vehicle for Towing?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

hatzie

I'm Awesome
Joined
Dec 27, 2015
Messages
100
Reaction score
146
Location
New Hampshire
Machine flushing is actually asking for trouble.
BTW I don't classify swapping the whole ATF oil charge by putting the trans cooler return line in a bucket to catch the nasty oil being pushed out by the fresh ATF you continually add to the pan as a flush. That's a 100% ATF change.
Drop the pan once and change the strainer. Add a Magnefine filter to the return fluid line from the coolers to clean things up. Then drain the pan without dropping it at shorter intervals... 2-3 oil changes and swap the fluid. I change my first Magnefine on a used rig at 1,000 miles and the next ones every 5,000 miles with the engine oil. The ATF is usually cleaner after the 2nd Magnefine than I used to get on two pan drains.


Yeah i didn't buy the 285s for the stability, I bought it for the extra off road capability and look, but I can feel the excess drag over 265s, which i had at one point. My pan already has a drain plug, actually, but with 251k on it I don't really want to touch it.
And luckily, all of the driving I'd do is between East Texas and Kansas, so just rolling hills. The trans temp gauge is a great idea actually.

The drag you feel may actually be a setup issue in the PCM. Your truck, if it's like most 3/4 ton GM trucks, came with 30.5" 245/75R16 tires. You need to change the parameters for the Transmission and Engine controls to reflect the 32.7" 285/70R17 tires you're running. Those 33s throw off the speedometer so it's showing a slower than actual speed but they also have your PCM pulling parameters from the wrong areas of the fuel, shift, and transmission pressure maps. You will perceive this as drag.
It's amazing what re-calibrating the PCM tire size will do to the driveability. If I hadn't just experienced the fairly extreme difference in driveability on my 2005 2500HD with just a 1.2" outside diameter calibration change between the PCM calibrated for the original 30.5" tires and the new 31.7" tires I wouldn't believe it.
My 2000 GMC C2500 has a 5 speed stick so I really don't feel much drag... Just went from the stock 245 to 265 tires on the same wheels and my tuner software won't touch the 6.5L ECM.
 
Last edited:

Supercharged111

Truly Awesome
Joined
Aug 20, 2015
Messages
12,614
Reaction score
15,238
You're using the transmissions pump then. How are you keeping it filled while it's running, just pouring it in from the top? I think most people when they here flush, assume the machine at a shop. Most of those have a pump, and don't use the transmissions own pump, which is where the contaminates are supposed to come from... Maybe they're pushing the fluid backwards? I've never studied it thoroughly as it's not something I plan to do.

Spec for a filter change is 6 or 7 quarts. I usually dump in 2 gallons and then idle to fill the empty jug. It fills up quick! Repeat as necessary. I pumped 4 gallons out of my 1500, 3 would have been enough but I still had sediment settle on the bottom of the 4th. Calling it an exchange vs a flush is fair. I've never done a flush on the machine. The horror stories there are sufficiently founded for me to stay away. The exchange method is far and away superior to a filter change. The fluid is cherry red after an exchange. Filter changes have always been a waste for me, the fluid is always still nasty after.
 

Dan_Frisbie

OBS Enthusiast
Joined
Nov 22, 2017
Messages
61
Reaction score
47
Location
Milton, FL
The shop flush machines (at least mine) uses the machine to exchange fluid, but the vehicle is running to circulate all of the fluid. It doesn't move dirt to other places, it removes it.
If you put any load on your rig, do this every 20,000 miles and your transmission will be happy and healthy.
 

454cid

Sooper Pooper
Joined
Sep 5, 2010
Messages
8,003
Reaction score
8,885
Location
The 26th State
The shop flush machines (at least mine) uses the machine to exchange fluid, but the vehicle is running to circulate all of the fluid. It doesn't move dirt to other places, it removes it.

Yeah, those are the machines I've read are actually safe to use. Other machines provide the pressure though, and those are the ones that are more common... at least that's my understanding of the situation.
 

Awest623

A juicy girl got me, again
Joined
Nov 23, 2017
Messages
745
Reaction score
512
Location
Washington State
Others already touched on it but I'll say it again, downsize your tires if you're planning to haul often. Either that or regear to 4.56. Also on your cam/crank misalignment. Check your dist gear for slop. The timing chain would have to stretch a LOT to throw that code.

Sent from my LG-SP320 using Tapatalk
 

Trenton

Just a Texan transplanted in the Rockies
Joined
Feb 2, 2017
Messages
206
Reaction score
198
Location
Aspen, Colorado
Machine flushing is actually asking for trouble.
BTW I don't classify swapping the whole ATF oil charge by putting the trans cooler return line in a bucket to catch the nasty oil being pushed out by the fresh ATF you continually add to the pan as a flush. That's a 100% ATF change.
Drop the pan once and change the strainer. Add a Magnefine filter to the return fluid line from the coolers to clean things up. Then drain the pan without dropping it at shorter intervals... 2-3 oil changes and swap the fluid. I change my first Magnefine on a used rig at 1,000 miles and the next ones every 5,000 miles with the engine oil. The ATF is usually cleaner after the 2nd Magnefine than I used to get on two pan drains.




The drag you feel may actually be a setup issue in the PCM. Your truck, if it's like most 3/4 ton GM trucks, came with 30.5" 245/75R16 tires. You need to change the parameters for the Transmission and Engine controls to reflect the 32.7" 285/70R17 tires you're running. Those 33s throw off the speedometer so it's showing a slower than actual speed but they also have your PCM pulling parameters from the wrong areas of the fuel, shift, and transmission pressure maps. You will perceive this as drag.
It's amazing what re-calibrating the PCM tire size will do to the driveability. If I hadn't just experienced the fairly extreme difference in driveability on my 2005 2500HD with just a 1.2" outside diameter calibration change between the PCM calibrated for the original 30.5" tires and the new 31.7" tires I wouldn't believe it.
My 2000 GMC C2500 has a 5 speed stick so I really don't feel much drag... Just went from the stock 245 to 265 tires on the same wheels and my tuner software won't touch the 6.5L ECM.

I actually planned on getting the truck tuned. Since I added the larger tires, cold air intake, and exhaust, I planned on redoing the timing chain and replacing an O2 sensor because the readings are starting to go inactive. I got on a Snap On tool at my work and while the other O2 sensors are constantly changing, the downstream Bank 1 sensor is going static. I'd likt o replace those first so that way BlackBear can tune without problems.
 

Trenton

Just a Texan transplanted in the Rockies
Joined
Feb 2, 2017
Messages
206
Reaction score
198
Location
Aspen, Colorado
251k and you're not gonna flush that trans? You're just asking for it. I feel guilty having not yet flushed my dually at 138k.
I don't know the service history of my truck. The fluid is fairly clean for the age, but I'd hate to screw up my transmission by rustling up particles when I change the fluid. I know the techs at the shop I work at are totally against a flush, but the safest bet is a pan-off filter/fluid change IF I want to. I'd like to throw in some Amsoil since I have it in everything else, but I hate messing with transmissions because of the unpredictability of them.
 

Supercharged111

Truly Awesome
Joined
Aug 20, 2015
Messages
12,614
Reaction score
15,238
I don't know the service history of my truck. The fluid is fairly clean for the age, but I'd hate to screw up my transmission by rustling up particles when I change the fluid. I know the techs at the shop I work at are totally against a flush, but the safest bet is a pan-off filter/fluid change IF I want to. I'd like to throw in some Amsoil since I have it in everything else, but I hate messing with transmissions because of the unpredictability of them.

This belief needs to go away. Read my other posts about how the fluid stays dirty with just a filter change.
 

454cid

Sooper Pooper
Joined
Sep 5, 2010
Messages
8,003
Reaction score
8,885
Location
The 26th State
I don't know the service history of my truck. The fluid is fairly clean for the age, but I'd hate to screw up my transmission by rustling up particles when I change the fluid. I know the techs at the shop I work at are totally against a flush, but the safest bet is a pan-off filter/fluid change IF I want to. I'd like to throw in some Amsoil since I have it in everything else, but I hate messing with transmissions because of the unpredictability of them.

If you have problems after a filter and fluid change the transmission was already worn.
 

jsfrmsj

I'm Awesome
Joined
Jul 7, 2016
Messages
142
Reaction score
106
Location
USA
meh, I had my transmission flushed at 160k, almost at 185k now with no issues. Original trans according to the previous owner (I bought it with 147k miles).
 
Top