New to me diesel TV

DC8Captain · 09-03-2018, 03:33 PM

Just traded in my Suburban 2500 with an 8.1L gas engine. At 10,000+ feet even it has a hard time pulling my TT. Got a 2500 crew cab with a 6.6L diesel and Allison transmission. I've never had a diesel engine vehicle before so I'm looking for cautions and suggestions reference the diesel engine. Also after reading the manual I'm not sure what and how the transmission brake works on the Allison. Is there something to do to engage it or is it automatically controlled. The manual wasn't very clear on this. No response is too simplistic here. My knowledge on diesels and the Allison tranny is lower than quail poop in a wagon rut.

ricemanwm · 09-03-2018, 05:22 PM

With my Duramax, when I enable tow/haul mode the transmission down shifts more aggressively when coming to a stop aiding in braking. If you would like more engine assisted braking enable the exhaust brake. I have found I don’t need exhaust braking where I live so I just enable the tow/haul mode when towing the travel trailer. The exhaust brake is ideal for long down hill runs coming out of the mountains.

87Yugo · 09-03-2018, 06:23 PM

I was told that there is less wear and tear when you use the exhaust brakes. True or not?

oldmanAZ · 09-03-2018, 07:04 PM

Certainly less wear on the vehicle and trailer brakes. I've never heard of engine braking being creating more drive-train wear.

curver900 · 09-11-2018, 12:45 PM

Quote:

Originally Posted by fdhealy4

Just traded in my Suburban 2500 with an 8.1L gas engine. At 10,000+ feet even it has a hard time pulling my TT. Got a 2500 crew cab with a 6.6L diesel and Allison transmission. I've never had a diesel engine vehicle before so I'm looking for cautions and suggestions reference the diesel engine. Also after reading the manual I'm not sure what and how the transmission brake works on the Allison. Is there something to do to engage it or is it automatically controlled. The manual wasn't very clear on this. No response is too simplistic here. My knowledge on diesels and the Allison tranny is lower than quail poop in a wagon rut.

edit :
there is much more maintenance depending on that.. fuel filters, the allison is pretty bullet proof make sure the fluid has been changed at no more than 75k, all the rest of the fluids changed too.. do them all.. depending on mileage, serpentine belt changed?, depending on the year some had issues with injectors but that was solved in 2007 ish...

use tow haul mode when towing the engine braking is automatic...

I had a 2005 and it was a nice truck just front end components weren't all that "stout" my 2010 ford had much better front end components...

pics of course always help

Seann45 · 09-11-2018, 01:23 PM

Change your fuel filter every time you change your oil.. injectors are expensive to replace.

Vasquez Kid · 09-11-2018, 01:59 PM

Congratulations on your new to you Duramax.

As my signature shows I have an 06 and I'm quite fond of it and the Allison transmission. This is my first diesel as well and I've had it almost 2 1/2 years. I've put on about 20k miles of the 265k that are on it now.

I bought this used truck to specifically tow my TT. I did have a bit of a learning curve as it does behave differently from a gasser. Mostly what I mean here is I had to get used to driving it in the RPM's 'sweet-spot' of 2k - give or take ~ 200 rpms. This is due to the peak torque being produced here. I found that revving it higher (like you might want to for a gasser) for a hill lets say, only started raising the coolant & trans temps. As I understand it this cycle actually gets started due to exhaust gas temperatures rising.

I invested $5 for the "Torque Pro" OBD2 app (android only I still believe) and a Bluetooth OBD2 adapter for $25. If you're an iPhone person another app out there is called "Dash Command" that can give you similar data. Of course you can always go with real-world gauges too. I'm bringing all of this up because I find it important to accurately monitor, at least, coolant and trans temps out here in sunny/hot Southern California while towing a heavy load. The factory gauges have proven to be very inaccurate.

It is also highly recommended that when you use a diesel you let it get up to full operating temps and then bring it down to normal temps before you shut it down. Bad examples would be to jump in it, quickly start out just to go around to the corner market. Also when coming home from towing letting it sit and idle for a few minutes before shutting down. I hear that this is best for the turbo's longevity as well.

Their is a huge aftermarket for the Duramax and you can go crazy with upgrades and mods. Lift pumps, tuners etc can be very effective. So far mine is mostly stock and i've only got a shot list of things that I'll do to it.

I could go on-and-on about the Duramax/Allison topic but you will find a ton of great info out there on the web. I would also go out and find an INDEPENDENT diesel mechanic that has a good reputation.

Take good care of it and it should drive circles around the gassers!

Cheers,

Jeff

6.6L Duramax LMM Specs & Information
Allison 1000 Transmission - GM Diesel Trucks - Diesel Power Magazine

tjpolsin · 09-11-2018, 04:55 PM

Quote:

Originally Posted by fdhealy4

Just traded in my Suburban 2500 with an 8.1L gas engine. At 10,000+ feet even it has a hard time pulling my TT. Got a 2500 crew cab with a 6.6L diesel and Allison transmission. I've never had a diesel engine vehicle before so I'm looking for cautions and suggestions reference the diesel engine. Also after reading the manual I'm not sure what and how the transmission brake works on the Allison. Is there something to do to engage it or is it automatically controlled. The manual wasn't very clear on this. No response is too simplistic here. My knowledge on diesels and the Allison tranny is lower than quail poop in a wagon rut.

I'm a Cummins' owner, but I can echo the rest of the responses here.
- Change your fluids at recommended intervals. Use a paper log (or find a digital app) to keep track.
- Fuel filter change is a must. Mine is good for 6 months. $50 if I do it myself, $150 if the dealer does it. Youtube is a good source to see if you want to tackle it.
- A diesel truck takes a while to spool up, so you won't get a sportscar launch from a stop sign.
- I engage my exhaust brake nearly everytime I drive; towing, highway, in town. No issues in 90K miles (and i'm still on my original front brakes)
- Turbo cool-down. Really only an issue if you are towing or hauling hard. My manual recommends up to 5 minutes max if I have been towing at max gross and have worked the engine hard. By the time I have exited the highway, found the fuel station, and parked, my turbo has cooled down.
- From your signature, it looks like you are from CO. Research an engine block heater for winter.
- Enjoy!!

Colorado · 09-11-2018, 08:08 PM

Diesel fuel in the States is DIRTY change the filter regularly. I use the additive below to prevent algae growth, control water too. It’ll also help with the amount your DEF cycles. Join a Chevy Forum that has a diesel specific section, they will help you with the do’s and downs of your specific truck, engine and transmission, they’ll help you fix things without having to take it to the dealer.

Archoil AR6200 Fuel Treatment TWO PACK - 2 x 16oz Bottles - Treats 1,000 gallons of fuel https://www.amazon.com/dp/B01N9QEVQL..._QphMBb71A1BQS

DC8Captain · 09-12-2018, 04:13 PM

Thanks everyone for your replies. I have read each one with interest and they also validate my suspicions that I knew very little about diesel engines. Any new folks to this thread please continue with your facts and observations.

Dale

vcbice · 09-14-2018, 09:10 AM

I also leave the exhaust brake engaged most of the time. On some models (especially VGT type turbochargers) you need to engage the engine brake frequently or the soot will bind it up over time (100,000miles). This was a common problem with the non-DEF Cummins. Wear and tear. Yes, the transmission is stressed more. On long downhills and heavily loaded I watch my trans temp (the torque converter generates a lot of heat). Only saw the temps rise once (10 miles of 6%).

Maintenance is more expensive with a diesel. Just look at how much oil they hold.

The cooldown part is important. The turbos get extremely hot when under load so you want to let it cool down a bit before shutting down (which stops oil flow to the turbo bearings). Turbos spin a very high RPM (up to 100,000 rpm) and need good oil flow. The owners manual will have a chart that shows cool down time for various conditions. When towing I usually do not shut the engine off unless I am stopping for more than 15 min. Yes, when fueling I leave the engine running. Stopping at a rest area we take turns and the engine runs.

I second the block heater for cold weather. Most wear takes place when starting (cold oil). Keeping it warmed is good insurance.

Tow/haul mode depends on the trailer/load. Our 7000lb trailer I never used it and rarely had to manually select gears. The 11,000lb trailer I engaged it all the time and on some hills would manually select the gear.

Have fun with the rig. Towing with the diesel is almost relaxing.

taviking22 · 09-14-2018, 10:21 AM

Congrats on your purchase! You are probably already loving what a diesel brings to towing capability.

I have the truck in my sig. The only thing I will add is that I bought the truck new and now am at 150k miles. The truck is stock except for Firestone Ride Rite Air Bags. Routine maintenance as said is key. I follow the DIC recommendations for oil change and fuel filter changes. When they are at 25% of life remaining I do the changes. In my opinion anything sooner is a bit of overkill and expense. But then clean oil and filters never hurt anything. (Guess I put my faith in the Isuzu and Chevy engineers) The rest of the maintenance needs I follow the owners manual recommendations. All this and the engine does not burn any noticeable crankcase oil.

About every 2 years I take the shroud off of the cooling stack/fan and give the radiator, tranny cooler, etc. a very good cleaning. It's amazing how many bugs and debris can accumulate.

I have had to replace glow plugs. But they are like replacing spark plugs if you are Houdini-like and can get into obstructed places.

I would recommend you visit dieselplace.com as I have learned a lot from the Duramax forum there.

Best wishes and happy and safe travels!

PlayersZ28 · 09-14-2018, 11:26 AM

Quote:

Originally Posted by Seann45

Change your fuel filter every time you change your oil.. injectors are expensive to replace.

That's a bit extreme. Water is the killer for the fuel system more so than dirt. I change the fuel filter every other oil change. My current Dmax has a fuel filter life count and it works out to every 3rd oil change (I stick to every other)

PlayersZ28 · 09-14-2018, 11:37 AM

My son's 05 DMax is getting close to 600,000km. Think this is the 4th one he's had. We've done head gaskets on it, couple of injectors, wiring issues, etc. They're a solid drivetrain as long as you are nice to them. Going crazy with filter and fluid changes doesn't help anybody but the parts supplier. The DIC is good with the oil change info, as mentioned do it at 10-25% area if you want, my son has run his past on numerous occasions. Watch where you buy fuel, water in the fuel is the bane of diesels. The trans has 2 filters, one outside and one inside. The Alison is a good trans but if you abuse it you'll pay. Stock power won't hurt it. My son & I both use Edge monitors for PID display. I watch EGT's pretty close when towing. I used to use Torque Pro but it was too much trouble and I found that the OBDLink adapter I was using would mess with the truck if I started the app when moving (on my '11 F350). Have fun with the DMax.

Fleetman · 09-19-2018, 02:09 PM

6.7 Powerstroke rules!! Diesel is the way to go for towing. Agreed as to the unnecessary overkill on fuel filter changes. My F250 let's me know when it's getting time. Use high quality filters, synthetic oil and parts, should run forever. When towing, even in rockies, I set my tow/haul mode and cruise control and let the brains of the unit do all the work. Only on occasion do I have to override with manual downshift.

kdhenson · 09-19-2018, 05:30 PM

Have a Cummins so I don’t know much about your set up but will give a word of caution concerning where to buy fuel on the road. I only buy fuel at reputable truck stops such as Love’’s and the other major stops. Reason #1: I know I can get in and out with my fifth wheel. Reason # 2 : although unfounded, I have been cautioned by career OTR driver friends to steer clear of the smaller stations. According to them the fuel quality isn’t as good and you are much more likely to get some water in your fuel system.

mohok1 · 09-19-2018, 06:37 PM

Hot Tip. If it is bone stock leave it that way. Don't change to a different air filter. Don't mess with success. I have a 2008 2500 HD Diesel Silverado (2nd owner) which I bought in 2010 with 32k miles on it. It had been used to tow a 5th Wheel and that is the primary use for me. Have 71k miles on it and have only had to change out the fuel lines as that yr model had a problem with the crimps. Went to a after market kit and had my dealer install for me.
No other problems. Fall in love with 'Tow Mode", it took me a while to do so but I think that is the way to go. Let the truck do what it was designed to do. Love my truck!!! Happy Trails!!!

LeonDawn · 09-20-2018, 05:20 AM

I have worked at a machine shop for over forty years and have become friends with many hot shot drivers. Probably 95% of them tell me the same thing. If you are towing anything use tow mode and exhaust brake. That being said I had the same questions. I took their advise. My wife and I just finished a 21 day 5885 mile trip from north of Houston to Seattle and back. We have a 09 Dodge Ram 3500 SRW pulling a Pinnacle 36 FBTS. We were loaded for 3 weeks close to 16K pounds. Going up mountains was a piece of cake and with tow mode and exhaust brake the big Dodge held me to 45 mph down several 6% plus downgrades 6 miles long. Made a true believer out of me!!

hboy · 09-20-2018, 07:39 AM

Quote:

Originally Posted by fdhealy4

I've never had a diesel engine vehicle before so I'm looking for cautions and suggestions reference the diesel engine. Also after reading the manual I'm not sure what and how the transmission brake works on the Allison. Is there something to do to engage it or is it automatically controlled.

Congrats on the new rig. If you have a later model duramax that has the engine brake then I would recommend using it often. It will save your brakes overtime and really helps out slowing down from highway speeds. If you don't have the engine brake and your referring to transmission downshifting during tow/haul mode- this is okay but nothing compared to the engine brake.

My experience with the diesel is more maintenance. The engine oil turns black within a couple hundred miles of being replaced. There are fuel filters/water separators that need changed.

I have noticed faster tire wear that I think is due to the extra weight on the front axle from the heavier engine. If it's a later model truck and requires DEF, I fill up at truck stops. Typically I put in about 2-3 gallons of DEF every 2-3 months. More frequently when towing heavy. Since the DEF has a shelf life, and depending on how many miles you drive it is feasible for the DEF to sit in that tank for months and months. I add a couple gallons at a time just to keep from sitting on old DEF.

I try to avoid short trips in town where the engine doesn't really get up to temp. If you have a short commute to work or activities frequently it may be better to use the gasser. I like it better when my driving takes me on the highway and the engine gets up to temp quickly and runs for a while.

Just my thoughts. Enjoy!

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