2008 GMC Towing mods/General Mods

[1970judge]

Hi all, first post here. I'll try to keep this short. I have pseudo inherited my brothers 08 GMC, 1500 5.3 LC9, CCSB Z71/4x4. It was parked a few years ago, he lost oil and figured it had finally let go. at the time I was out of state (im the family car guy) so couldnt look at it. Fast forward, i moved back, got around to it..fired up..no issues. I added some oil, filter, etc. My guess is the local goons overfilled it and it popped the filter. SUMARRY AT VERY BOTTOM

Anyway, he gave the green-light to utilize it for Daily-ing and towing my track car. Looking for opinions. Ive done a TON of research here lately, but there is one thing I am unclear on. (Scroll down for that if you dont want to read any further).

Needs: to tow a 3,837LB Z/28 (2015). Thumbing around online, choosing a good trailer, should be within spec here.

Want: It has 250k miles, it needs some TLC. Ive built many of rowdy LSx engines, and thats not what im after. Small cam, dod delete/afm etc, i'll probably do some mild porting etc. Just looking for some more torque. For those that use a 1500 to tow, any trans cooling mods to be done? I'll add a larger cooler up front, but anything else? better pan options? Obviously the stock 4l60e also has 250k on it. Anyone using the TSP low lift cams? Im looking in that range, to not lose any low end, and gain a little mid to high. Probably use a short tube header as well, not long tubes. Pretty much the entire suspension/ujoint have never been servies, so that'll get done to.
 

What I do not know! I stopped working at a performance shop around 2008, and just altogether stopped paying attention to things. What 'years'/RPO's will drop in with no work (extension harnesses, reluctor wheels...etc) that are 4.00+ bore. What I gathered is as long as im using Gen IV engines im good. I ask because idealy, eventually, id find an L92/LS3 or 6.0 to drop in (L92 was the business when I was getting out of performance stuff). Just looking for basically anything to drop it that is 4.00+ bore, but  thats down the road.

Summary version:    08 CCSB, 5.3, 4x4 with 250k miles needs to reliably tow a 3837lb car. Any experience with the TSP low lift cam? What Short tube headers have people run? What trans cooling mods (bigger coolers/better pans) have people run? For future reference, What RPO engines are absolute, direct drop in? (6.0/6.2 RPO's).



 

[swathdiver]

Welcome to the forum.  Most fellas choose the Tru-Cool Max 40K transmission cooler.  PML makes pans with fins, stock depth and deeper, same for rear axle.

 

Shorties work fine and keep bottom end though many will disagree.  Exhaust on 5.3 is 2.75" and any larger will kill bottom end.  I personally think those TSP cams are still too big for a truck, I like the Cam Motion and Crane and Vinci cams that can run the stock springs.  All that duration and lift moves the powerband away from where a truck wants it IMO.  You can ask these questions over at the Performance Trucks forum and for the shorty headers, over at the TahoeYukon forum, look up KBUSKILL, aka Ken.  He has shorties and a custom exhaust on his Suburban and did not want to lose bottom end torque, spent a lot of time by trial and error to get it right.  Good man to talk to about that.

 

The 2007-2009 5.3s do not have VVT.  All of the 6.0 and 6.2 motors have VVT.  It is not hard to add the wiring or pin the ECM if you don't get one with a donor motor.

 

The LC9 is Flex Fuel capable, you can run E85 or any amount of Ethanol you want to make more power or pay less per mile if it is cheap enough.  The engines love the stuff.  

 

For 6.0 motors these are your choices: L76, LY6 and L96

For 6.2 Motors these are your choices: L92, L9H and L94

 

None of these engines used the 4L65E.  The L76 used the 4L70 and 6L80 in some pickups, the LY6 used the 4L80 for a year before switching over to the 6L90.  all of the 6.2s use the 6L80.

 

Use this link to educate yourself about all of those engines.

https://help.summitracing.com/app/answers/detail/a_id/4854/~/chevy-lc9-engine-specs

 

 

She should tow fine, you just have to slow down.  GT4 means she has 3.73 gears.

Edited September 21, 2019 by swathdiver
Additional Information

[SierraHD17]

Shorties are useless with their 1 5/8" primary tubes... you are better off with the stock exhaust manifolds as a short tube will do nothing for power and just make noise. 

 

The tsp high lift version will make more torque than the low lift... that's a fact.  You have a decent base with a 9.9:1 compression 5.3. Vinci is another truck oriented cam grinder and some of his setups are worth your time.  

 

Your 60e won't live long lol so prepare for a rebuild.  A big cooler and modest tuning is about the best you can do.  A 6 cylinder trailblazer torque converter is a nice little bump that stalls around 2400 rpm muchike the stock 4l80e one does behind the 6 liters.

 

Don't even look for an L76 as it's just an afm disaster and people want more for nothing with it.  Just like the L94 6.2...

 

I'm mixed on the 6.2s lol... might get a good one or get a rattly bottom end problem dud like the two I have lol.  One of mine has 53000 miles and the other has 70000 lol.  I'm seeing about getting the new 6.6 direct injected engines crank and rods to rebuild the 70k mile one and swap it in my 6.2 truck.  I like torque too and have a 216/228 cam for vvt it will like.

 

Honestly the LY6 or L96 6 liters are rock solid and cheap and easy to find.  Worst case mill the heads and take the cam from the 5.3 afterwards.  An even better combo is to sell the L92 heads and use the 243s off the 5.3 on the 6.0... way better lower rpm pulling power especially if you delete the VVT and bumps compression to around 10.3:1.  

Edited September 21, 2019 by SierraHD17

[intheburbs]

I say run what you brung.  You have the heavy duty cooling package (KNP) and 3.73 gears (GT4).  Sure the transmission has a lot of miles on it - any mods to improve engine output will just accelerate failure.  If the transmission blows up, it blows up.  No point in throwing money into it now.

 

With the trailer, you're at about 5000 lbs.  Assuming you'll go flatbed, not enclosed, the truck should tow that pretty well.   See how it does, how the temps run, and then assess and plan your mods.

 

[1970judge]

Thanks for the feedback. I agree run what ya brung is mostly what i'll end up doing, a small bump in power aside. I'll baseline it eventually pulling it from here to Houston at some point, that way if it breaks i'll be close to home. Ideally, it would be ready to haul long term by next fall, wouldnt mind making it out to LV for a yearly track event at LV motor speedway. Around these parts its mostly flat, so shouldn't be super hard on the truck initially.

One thing of note: replying to the First replier. These LC9's DO have VVT/AFM as far as I know, or am I wrong on this (FWIW this truck ground the cam down at 100k, which I told him to Delete it/cam swap it then but he didnt listen). I intend to, if nothing else, rid this truck of that garbage.

[CamGTP]

2008 does not have VVT. That is 2010+ for a 5.3 engine, your truck only has AFM/DoD.

 

The same basics will apply for the delete though. New cam, cam gear, lifters, pushrods, valley plate, gaskets etc etc plus the custom tune.

[1970judge]

9 hours ago, CamGTP said:

2008 does not have VVT. That is 2010+ for a 5.3 engine, your truck only has AFM/DoD.

 

The same basics will apply for the delete though. New cam, cam gear, lifters, pushrods, valley plate, gaskets etc etc plus the custom tune.

Thanks for clearing that up! Ive read it both ways, but you know, internet inaccuracies and such, wasnt sure.