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01 CCLB D/A K3500 DRW sitting in the yard...

GM Guy

GM Guy

Manual Trans. 2WD Enthusiast
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Location
NW Kansas and SC Idaho
Hey all,

Got a 2001 Chevy K3500 DRW Duramax/ Allison CCLB pickup sitting in the yard, hopefully i did not screw up on price.... Under 5 grand.

Engine runs like a top, supposed to have had new injectors 3 years ago, and it fires right up, no smoke, and no blowby, so it seems the engine is solid. Truck has 238,596 on it for miles.

The transmission is the part that is worrying me, I bought it with the issue known, so its a gamble I knew I was taking on.

I am exploring the issues with it at this thread as to not de-rail this one: http://www.thetruckstop.us/forum/threads/how-common-is-a-bad-shift-cable.44863/#post-511668

So, I ask you guys, what needs done to it first after I get the trans going?

I am thinking oil and all filters changed, but past that, what needs adressed on a LB7?

how well will it tow when bone stock? I will be pulling as heavy if not heavier than the 6.5L fleet, so it will be worked some for sure.

Is there any weak spots like cooler lines and harmonic dampers? Basically all I was aware of was the t-case pump rub, but past that I dont know squat.

Any input appreciated!

thanks!
 
Get some upgraded trans cooler lines and an upgraded Mike L cooler. I changed fluid every 25-30k (drain and refill), spin on every oil change (10k for me).

Other wise a pcv reroute, lift pump (Leroy can hook you up), and good primary filter. Keep up with a fuel lube treatment.

It will pull just fine stock, it will pull great with a single efi live tow tune.
 
Dexron 3 OK?

Also, how hard are the t-stats to change? It didnt seem to want to warm up too quick, but it was just idling for about 10 minutes.

Keep in mind the only mods I am doing is for durability/ longevity, gotta keep it cheap if I am going to re-sell it to buy a ZF6 2wd. :) Only reason I bought this one is due to the price, in case anyone thought I have gone insane... :)
 
I think you are going to like it better than you think. ZF6 isn't all its cracked up to be after driving one.

T Stats can be done in under 1hr. My 06 wouldn't idle to temp in the cold BTW.

Those mods I mentioned are for longevity of injectors and the trans. IMO a light efi live tune for the trans helps alot.
 
tanman_2006 said:
Get some upgraded trans cooler lines and an upgraded Mike L cooler. I changed fluid every 25-30k (drain and refill), spin on every oil change (10k for me).

Other wise a pcv reroute, lift pump (Leroy can hook you up), and good primary filter. Keep up with a fuel lube treatment.

It will pull just fine stock, it will pull great with a single efi live tow tune.
Click to expand...
Upgraded trans cooler lines are good, but I see no reason for the MIKE L cooler. You can buy an EARLS for a good bit less money, and adapter fittings to hook it up easily enough. There is no need for a PCV reroute on an LB7 as it already vents to atmosphere after it goes through a plastic catch can. The LB7 system is FAR superior to a re routed and just vented to atmosphere system. If you install a lift pump, go with a flow on fail pump, otherwise if it quits working, you're walking. I like my KENNEDY pump as it's extremely quiet, draws very little current, and flows ALOT of LOW pressure fuel. Not sure if Leroy has access to this style pump or not, but they work great for stock or lightly modified DURAMAX's. Leroy does have a nice pre filter for your lift pump which is basically what I'm running. Also ONLY run the METAL fuel filters. Careful with tuning on 5 speed ALLISON trucks as the stock 5 speed ALLISON isn't the strongest, I don't reccomend more than a 35HP tune for one thats going to do much towing.
 
GM Guy said:
Dexron 3 OK?

Also, how hard are the t-stats to change? It didnt seem to want to warm up too quick, but it was just idling for about 10 minutes.

Keep in mind the only mods I am doing is for durability/ longevity, gotta keep it cheap if I am going to re-sell it to buy a ZF6 2wd. :) Only reason I bought this one is due to the price, in case anyone thought I have gone insane... :)
Click to expand...
TES-389 fluid or DEX/MERC is what you want to use. DO NOT USE ANYTHING THAT SAYS IT'S COMPATIBLE WITH DEX VI! It will DESTROY ALL your seals in the trans in SHORT order. Stats aren't bad t odo at all, alot easier to do than on later model trucks. pop the oil fill tube out(stuff a rag in the hole), Remove the one bolt that hholds the coolant outlet tube to the t-stat housing, remove the 4 bolts that hold the t-stat housing in, and slide the housing out the front. Do not remove the A/C compressor as this will almost gurantee you that you will ruin your compressor. The R6 compressors shift when unbolted under pressure, and the seals that seal the housing will twist and leak. Also ONLY use AC delco or OEM stats, aftermarkets will not warm up at all unless your under load.
 
Ferm with good info as always.

I didn't know that about lb7 pcv, the mike l was just an example I ran dual Leroydiesel engine oil coolers for my trans (what was on hand lol). I run the fass 150 but I think a raptor 90 would be fine stock with a prefilter. Never used the Kennedy pump but I hear it's an industrial type pump.

On the efi live tune I just meant a light tow tune to wake it up a hair and maybe help out on shifting, nothing crazy.
 
Only going from what I have read. I would do the lift pump for sure. A cheap friend has a Duramax and was fighting things because he didn't want to pay for the lift pump upgrade.

Personally I prefer a lift pump that makes enough noise that I can hear it run when all is quiet. The Jeep is so quiet, I can not hear it run when it is jumpered to prime the fuel filter. It's an in tank model, so that may make a difference. I'm still thinking I might have should have used a lift pump for a 93 6.5

I would also do the FS2500 bypass filter.

I am assuming since you bought it, that it is 2 wheel drive
 
Maybe an LB7 is significantly different but I have plenty of performance from the LBZ running a plus 85 Predator tune and stock fuel system
 
Good news!

Stopped by the local GM dealer, and its had some $ spent on it.

Injectors in 08 @ 160K
T-case in 13 @ 200?K
Front end rebuilt in 13 @200K
had I believe both the booster and the master for the brakes, power steering pump, high pressure line from pump to steering box, etc. I think also in 13

It did have the cable replaced in 13, so I am wondering if they did it wrong, or if the NSBU is causing issues. cable is 117 from GM, and NSBU is 199.

I think I will wash it out and get some lube on the shaft, and see if I can get stuff to free up, if not, I guess cable from GM, and a NSBU and a 6 pack of filters from Allison.
 
jrsavoie said:
Only going from what I have read. I would do the lift pump for sure. A cheap friend has a Duramax and was fighting things because he didn't want to pay for the lift pump upgrade.

Personally I prefer a lift pump that makes enough noise that I can hear it run when all is quiet. The Jeep is so quiet, I can not hear it run when it is jumpered to prime the fuel filter. It's an in tank model, so that may make a difference. I'm still thinking I might have should have used a lift pump for a 93 6.5

I would also do the FS2500 bypass filter.

I am assuming since you bought it, that it is 2 wheel drive
Click to expand...

Automatic, 4wd. :O Remember Jeff, price is a major reason its in the yard, pretty hard to pass up. :)

Tanner, I am sure the ZF6 is not all that its cracked up to be, as i hear they use cheaper components than the Ford ZF6, but the NV4500 is pretty underwhelming too, with its wide 3-4 gap, and I am manual tranmission loyal to a fault. :)

Plus, all I can think of right now, is that ZF6s dont have a cable or a NSBU.... :)

IMO for mpg comparing a ZF6 to a 5 speed Ally, the ZF6 would probably come out on top, maybe the 6 speed double OD ally would beat them all. I do know I was NOT impressed on LBZ mileage when my buddy offered to pull my trailer to California so he could see the sights (I paid fuel and gave him a Tekonsha Prodigy P3) I was impressed on power though. :)

With that in mind, how out of the question is it to 6 speed ally swap a LB7?
 
What condition is the truck in interior why's?

Would it be something I would be interested in? Cindy doesn't like the NV4500 in the truck and she has ended up driving it quite often for some reason.
 
If you decide to sell it for a reasonable price I might be interested.

A friend bought a zf6 equiped truck, gets a whole 16mpg highway, trans is kinda loud, clutch didn't hold stock power pulling a stock trailer. He quickly pawned it off and got the same truck with an auto.

Since your truck a new tcase it should be smooth sailing from here on out
 
Stock the LB7 is not that bad, the only real drawback in stock form is the fueling delay from a stop. With a regular wastegated turbo, it doesn't spool up very quickly when set to be smoke free. The 5 speed ALLISON is NOT going to hold much power if used for towing, it's no where near as strong as the 6 speed(and the 01-02 is the weakest). MPG will be almost identical if not slightly better with the ALLISON honestly. They both have 3.73 gears(ALL DURAMAX's come with 3.73 gears stock), and the OD ratio of both is pretty close. The ALLISON keeps the turbo lit, and doesn't drop out of fueling when shifting which actually helps to keep the engine up in the power band.

DO NOT BUY THE NSBU FROM GM! They will RAPE you for it. The same exact NSBU from ALLISON will be about $70. Spin on filters are $8 a piece at my local ALLISON dealer, GM paints em blue, and marks em up to $50 list price(normally sell for $30). Like I put in your other post, I doubt your NSBU is bad, the P0841 code is BAD JUJU, and will require some diagnostics to find the problem, not throwing parts at it as it is indicative of an internal problem to the valve body or C solenoid control circuit. And a 6 speed conversion will NEVER pay for itself in fuel savings. I believe the kit is up around $2K now, and on average most only see a .5MPG(YES a HALF a MPG), with most saying the best is a 1.5MPG improvement. Stock SRW LB7's are KNOWN to get 20 MPG if driven easy at 70, as LB7's got the best milage stock(tuned the newer trucks seem to do a little better, but stock the LB7 is king).

Disconnect the shift cable, and see if it the shift shaft moves fairly easily at the trans FIRST. As to your trans issue, get out your DVOM, and start checking the wiring for the C shift solenoid.
 
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