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Seeking advice on a 96 Chevy 3500HD 6.5T w/ 4L80E for hauling a GN 2 car trailer

J

just-j

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Location
Phoenix, Arizona
I recently bought a 96 Chevy 3500HD Crew Cab w/ 6.5T & 4L80E trans. 126K mi.

This is a pretty HD truck 19.5 wheels, Straight axle 15k GVWR.

The plan is use to 3500HD to haul a GN 2 car trailer.

What do I need to do, to bring the truck up to the task ?? Engine / trans ??

Would welcome to any inputs, thoughts etc.

Thx for looking
 
Need to know more about the truck. What turbo, any tune, hows it doing with heat, etc? How is it towing for you now? What is your budget and time line?

The biggest thing to help is loose the gm turbo if still on there and get ATT, hx40, etc. with 4" exhaust. New set of german bosch injectors is next on the list. Let us know all you can about it.
 
Buy one of each from my web site ;)
www.leroydiesel.com

What is your budget?
First things are Exhaust, K47 intake, LP capable of at least 9psi at the IP. The list go's on and on, but that will get you going.
Down the road a better turbo like the ATT will help a lot.

Edit: Will posted as I was typing so x2 on some ?
 
Hi

I haven't towed anything with it yet!
My budget ...I guess would @ $2,500 ?

I guess the exhaust would need to be upgraded....3" to a 4" or 5" ??
better injectors...
More efficient turbo setup ...from what I've read A-team, ATT, HX40II ??
Some type of "tune" for the ECM ??
A trans shift kit ?
Hopefully, this will get me where I need to be.....towing a 2 car trailer reliably ?

Would appreciate hearing from "warwagon" since we're fairly close in N. Phoenix /Scottsdale area.
 
Yes, there are a number of things for upgrading. My vote is to first figure out the overall health of the truck.

First thing I'd do is run it for 2K miles as-is on the same oil and get an oil analysis. This will help with determining whether the motor needs any immediate work and help set the priority of upgrades / repairs.

With 126K miles on the odometer, unless there is known repair history, plan on replacing the injection pump and injectors (at a minimum) now rather than later.

For getting 'better' injectors, it is not like a DI which can get more flow through them. The choices pretty much are OE-ish or marine. Best route for the injectors is to make sure the guts are Bosch and their pop-off pressures are equal (or nearly equal). In terms of what style (OE versus marine) and pop pressure, this depends on other parts like the turbo and your personal philosophy.

For the tranny, my vote is just to make sure it seems healthy. From everything I have read, a shift kit is Ok where tuners can do nearly the same thing. Also, if you do put in a shift kit, the tuners will need to know so they can adjust the tune to account for it.
 
Ohh, and check out your harmonic balancer! No power there, but the lower ends on these engines suck. Bad balancer will snap a crank / crack block.

Give WW some time, I'm sure he'll chime in.
 
The truck should pull the load if you know that your not going to be able to keep up with traffic... these motors are fuel mizzers, they can pull but just don't expect to pull those long hills out your way at 70 mph.....

Being a HD, what rear gear ya got?? how many rpm's ya run when towing that load???
 
tanman_2006 said:
That truck ended up with a dmax

I'd try the ATT, tune, and supporting mods
Click to expand...


Not only did it end up with a Dmax, but, he managed to hurt that a couple times too. It's the nature of long hard heavy hauling. Duramax parts are expensive. So are Cummins parts. But they have more power and reliability being used hard. Oil changes alone are 10K on the better engines where the 6.5 is every 2500 miles, yes, doesn't even make 3000 miles! UOA will let you know if you can get the next 500 miles out of the oil the next change. Local "Lab One" is under $10 per sample with TBN if you get the 10 pack: http://www.laboneinc.com/ You need a rainy day fund for when your engine lets go or other major repairs. IMO you have a starter truck that should be upgraded to something else if you find it profitable.

Welcome. And my experience is your next door neighbor so I know the grades around here in most directions that go for miles in brutal heat. The More Power Scotty comment isn't a NEED for 1000 HP and 1000 Ft lbs of TQ - it's that 200 HP and 400 lb-ft is wide open slowing down on the grades here and 305 HP and 555 lb-ft has power to spare not working so hard.

The biggest improvement to power, MPG, and cooling on a 6.5TD are all on getting the GM turbo off the engine. Personally I would stall it with the ATT to bring the 6.5 into the ATT's power band from a light and use the triple disc converter clutch when up to speed. (The Turbine Diverter Valve keeps more heat in the engine so I prefer the stall converter over a Turbine Diverter Valve. link.) The triple disc eliminated the 4L80E's weak point of the converter clutch. Do NOT compression brake with the TCC locked as the other weak point is the manual 3rd (or second?) small overrun clutches.

When your trans lets go local good prices and good quality: http://www.allstatetransmission.net/

http://www.thetruckstop.us/forum/threads/let-the-insanity-begin-time-to-yank-it.43647/

Words may not do justice to saying you need to spend money on a better turbo for the job and getting the engine into the RPM power band. Be mindful of your gearing as to if a stall converter will work for you. Here is an article on improvements I found towing hard with a 6.5 TD as well as the carnage learning along the way.
The 6.5L Diesel Factory Equipped Asthma Attack:

http://www.maxxtorque.com/2012/07/the-65l-diesel-factory-equipped-asthma.html
 
Burning oil said:
Buy one of each from my web site ;)
www.leroydiesel.com

What is your budget?
First things are Exhaust, K47 intake, LP capable of at least 9psi at the IP. The list go's on and on, but that will get you going.
Down the road a better turbo like the ATT will help a lot.

Edit: Will posted as I was typing so x2 on some ?
Click to expand...

No joke. Seriously The Walbro Lift pump and the indestructible fuel level sensor he sells are a couple of mods that will save you time and frustration. The factory lift pump doesn't last out here. Biodiesel is another nightmare to be aware of: http://www.thetruckstop.us/forum/th...ulsd-and-biodiesel-this-can-affect-you.35096/

I forget what alternator you have for 1996. If it's on the driver's side with the s#itty R4 compressor on the passenger side you need to upgrade the alternator to the CS-144. The newer years had better and offhand I forget what year GM changed it let alone midyear production change etc.
 
First off, welcome to the forum, and congrats on having such a rare truck! Technically, the crew cab C3500HD did not even exist, but a few big buyers, such as Union Pacific were able to get them bought. They were not in the brochure and a regular small order buyer could not get them.

check and see what rear end gears the big girl has, it will either be 4.63 or 5.13.

I have been doing some small time hotshotting with 6.5Ls, and have had excellent luck, alot of which I credit to the 5 speed manual. The 4L80E is pretty strong, and many have good luck with it, so I would not swap just because. If she goes down, I have long pondered a Allison swap, and the HD should have more room underneath to get it to fit.

Take it from someone who just burnt up the engine on a 93 K2500HD with the factory turbo. You wont get along well with a factory turbo unless you baby it.

Also, another thing to keep in mind with the big HD is that there will need to be modifications made to whatever exhaust you install, as the down pipe is longer. So basically buy a Diamond Eye, but you will need to mod the down pipe.

So, If I were you, I think the smartest route would be:

Fluidampr, and a fresh damper pulley (and crank seal of course)
Diamond eye 4 inch exhaust
A-Team Turbo
K47 air box or S&B (absolutely do not go with a cheap "CAI" as most of the time they are the opposite, a hot air intake)

99.5-00 (order for a 2000 model year C3500) water pump and fan clutch, and a 01-04 (order for an 01 to be safe) Duramax fan. Try to go genuine OE grade AC Delco on the WP at least, and preferably the other parts as well.

The rear end is a Dana 80. I would order a Mag-Hytec Diff cover for it and some 75w140 or 85w140 synthetic gear oil for it. It has a slight flaw in its design, and is pretty hard on oil. GM recommended changed the 80w90 every 3K miles, or 75w140 synthetic ever 30K miles. when shopping for the diff cover, it will commonly be referred to as a dodge application. The axles are quite different, but the center section has the same cover pattern so dont be worried ordering a dodge dana 80 cover for your GM dana 80. :)

Also consider a deep pan and synthetic oil for the transmission as well.

Check over the disc brakes, rear discs are a little high maintenance IMO. Make sure your parking brake warning light works, quick way to cook the rear seal out of the transmission if you forget and leave it on. :)

Past that, maintenance is the biggie, I like to fairly quickly get stuff switched over to AC Delco professional grade USA made greaseable u-joints, and physically remove the radiator and clean everything.

For engine oil, I run Mobil Delvac 1300 super conventional grade, and once I find a vehicle that does not allready have oil leaks, I will be switching to synthetic. :) many seem to be quite happy with Amsoil.


As far as parts sources, mine are: Leroydiesel.com (owner of the business, Leroy himself, is username Burning Oil above) a good local GM Dealer (buddy up to one, should be able to get 15 percent off if you are a good customer, also a good one will be VERY helpful looking up parts) ebay, amazon, and rockauto.com.



Also, this is one of the top 2 6.5L diesel related sites, so you are in good hands. :)

There is one, and only one 3500HD forum, at what other address than www.3500HD.com. :) It is good info for HD specific stuff, and guys can help find HD specific parts. not very high traffic, but they are all still actively posting.

A word of advice, keep track of expenses, try to squirrel away $ for repairs and upgrades, and track mpg, and most of all, try to get high $ loads, as hot-shotting is not usually a huge money maker. :)

Good luck!
 
Looked over the truck in person. It has a GM crate engine in it, but, some miles so the markings are covered in oil creep. The Water pump has HO marked in it. Single rare reverse t-stat housing. Turned off the MAP related SES light and it got 10 MPH more...

Heavy service truck bed and crane removed. After a tour around the bock it really needs some mods to wake it up. Watching the engine not rev up floored gave me flashbacks to trying to tow with patch before the turbo was changed to the ATT and trans tune to shift to the powerband.

Hopefully the ride in patch gave him so ideas of what's possible. IF the project truck in the garage didn't scare em off!
 
Last edited:
hopefully you didnt scare him off! lol

Still amazed no pickup mfg.er wont give you a cheap or free lease to test a new truck to the max. :)
 
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