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2005 chevy trailblazer_ls
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251 Posts
Discussion Starter · #1 ·
Well I just bought a 16' toy hauler in upstate NY and towed it home. I was not happy I couldn't keep a constant highway speed of 65.
My TB is a 6 cyl with a 3.73 rear and 32" tires. The trailer unloaded weighs 3500 lbs. I can maintain 65 on flat ground with no head wind or while drafting anyone in traffic however on the open road the slightest increase in required power the trans downshifts. I swear that trans drove through the entire Catskill Mountains in second at 4000+ rpm

It runs about 25-2800 rpm in third at 65 and then jumps to 42-4300 rpm when it downshifts to second.

The truck pulls a 2200 lb trailer fine and even with the 3500 lb trailer accelerates fine to highway speeds it just wont maintain them. Its like I'm right on the edge of the power band. If this were a trans with a shift detent I would probably try and adjust it for a little later shifts.

PS the trailer will weigh in at about 4700 loaded.

I'd like to know if and how a tune might help me out? Any experience here?
 

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Basic Vendor- Skid Plates
2007 chevy trailblazer_ls
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3,700 Posts
The 32" tires are probably your killer, there... Your 3.73 gears are now 3.55 gears, and 65mph is actually 68mph... Not big differences, but when you're talking about towing a brick, and 60-65mph being the breakover point where wind really starts to have a larger effect, it is a big deal...

A tune with later shifts will cause it to downshift sooner.

A tune will, however, increase your static timing, and should give you more power...

If you're out of warranty, it can't hurt...

Mike
 

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2002 chevy trailblazer_ltz
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3,250 Posts
IMO, getting a towing specific tune should help you. The tune will tailor the PCM to give you power where you need it in the power band, and allow correct shifts.

If you go with someone like PCM4Less, you simply tell them what your towing, how often, the weights involved, rear gear ratio, etc, etc., and they should be able to come with something that will help. Give them a call....ask for Kelly.

Take a look at this thread.....should give you a good idea of who they are and what they can do for you, plus their phone # is there too.

http://forums.trailvoy.com/showthread.php?t=43984
 

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2005 chevy trailblazer_ls
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251 Posts
Discussion Starter · #4 ·
Well it's gonna have to wait now. Blew a exhaust manifold gasket yesterday. Already fixed. One broken manifold bold and a new manifold along with the gasket. The gasket actually let go because the bolt was broken. I did the manifold because of all the threads on here about cracks.

Total cost for the manifold, exhaust gasket, donut gasket manifold bolts and misc hardware $215 and about 4 hours of sweat to get that very back lower bolt out!
 
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