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Any advice for towing....

Ernie12

Full Member
Joined
Aug 16, 2010
Messages
125
I just traded in my 06 z71 with 3.42 axle for a 2012 LT 3.08 6speed trans., This truck is a little different to say the least.  I tow a 5000 LB boat when loaded with gear in the summer and would like some advice.

Do you guys just put it in drive and use Tow mode?  Would this be the best way as not to burn up the tranny?  Any advice would be appreciated .
 
Are you in a hilly area if you are I would use drive or even manual

Since you have the 3.08 gear you may want to see if you have a tranny cooler.
 
Ok Im a little confused now I looked at my RPO codes and it lists      GU6  which is Rear axle, 3.42 ratio   is there another way I can confirm this?

The dealer had it listed as 3.08 

I checked and I do have the Tranny cooler. Its small but its there.
 
Ernie12 said:
I checked and I do have the Tranny cooler. Its small but its there.

Just to be certain, if your truck is like mine, and it most likely is, there will be a "smaller" cooler that is mounted vertically in front of the radiator on the driver's side.

That is a cooler for the power steering fluid.

My factory aux transmission cooler can be seen mounted right in the lower center in front of the radiator and it is horizontally mounted, is larger than the power steering cooler, and measures right at 12" from side to side.

Others have assumed the smaller cooler was for engine oil or the transmission, but that is not the case.

If you have a factory engine oil cooler, the lines are routed into fittings on the driver's side rear of the radiator.

The regular transmission cooling lines run into fittings on the rear of the passenger side of the radiator.

With the aux transmission cooler, the fluid is routed into the regular cooler inside the radiator, then the fluid passes through a set of lines to the aux cooler in front of the radiator, then the fluid is returned to the transmission.

Hope this helps identify your set up.

Of course, this all is assuming the second gen trucks are similar to the first gen trucks.

And you know where assuming can get us.

(y)
 
Thanks EXT thats the same setup I have.  Now about the axel since the RPO codes says  GU6 I must have the 3.42  and not the 3.08 like the dealer listing.
 
I've never heard of a 3.08 rear gear. Seems like both 3.08 or 3.42s would be making the truck shift down a lot.
I haul a 5k lb boat too.....with 4.10s.
 
Starting in the 09 model 3.08 were standard for improved gas mileage, 3.42 were optional.
 
It sounds like a high gear for the rear, but with the six speed trans 1st and 2nd gear are lower so off the line performance with 3.42's is similar to 4.10's but like MS03 2500 said mileage is better because of lower RPM on the highway.

While towing depending on load and grade you may need to keep in a lower gear to prevent the trans from gear hunting..
 
Well I towed my boat the other day and my engine started to overheat a little so I checked the transmission temp and it was overheating also hovering around 225  and that is not good.



Do any of you guys recommend a certain type of Transcooler to install? I saw one on Etrailer that looks pretty good and install doesnt look to bad.
 
Ernie12 said:
Well I towed my boat the other day and my engine started to overheat a little so I checked the transmission temp and it was overheating also hovering around 225  and that is not good.



Do any of you guys recommend a certain type of Transcooler to install? I saw one on Etrailer that looks pretty good and install doesnt look to bad.

225 is still supposedly OK with Dexron VI; I don't condone running tranny fluid temps that high but fact is I see those temperatures on my 2012 Corvette in 95+ degree temperatures.

I prefer stacked plate transmission coolers like a B&M Supercooler or a Long Manufacturing Tru-Cool unit (they supposedly make the B&M units). Get the unit with a low temperature bypass in it; this will assure the fluid bypasses the cooler in the winter until the fluid gets warm enough (gets less viscous and flows more easily); too-cool transmission fluid is almost as bad as too-hot. The larger the unit the better. Plumb the auxiliary cooler after the radiator cooler so that it is adding additional cooling on the way back to the transmission.
 
GU6 is a 3.42 rear... check for K5L, that is the heavy duty trailering package that includes the extra trans cooler. My truck also has KC4 and KNP which are codes for oil and trans cooling systems. I tow my 5000lbs boat in tow/haul mode, the mileage sucks but it keeps the RPMs up and stops unnecessary shifts. I also keep an eye on trans oil temp on the DIC.
 
greatgab said:
GU6 is a 3.42 rear... check for K5L, that is the heavy duty trailering package that includes the extra trans cooler. My truck also has KC4 and KNP which are codes for oil and trans cooling systems. I tow my 5000lbs boat in tow/haul mode, the mileage sucks but it keeps the RPMs up and stops unnecessary shifts. I also keep an eye on trans oil temp on the DIC.


Thanks GreatGab,  I have all of those codes also . I tried towing in D with trailer mode and the trans get pretty hot. Also tried it in manual experimenting with different gears with and without tow mode but it still keeps getting to hot. Definitely looking into a larger trans cooler before my next tow.
 
I tow 6,000 Ibs and got to 212 degrees for the first time ever after 3 Avalanches all with HD cooling (Tow systems) this past summer. Maybe Global warming (ha). Is 212 still ok... sounds like I'm still ok. I tow in northern Ontario so its maybe 80 degrees ambient temp in summer. Sound ok, or should I look for more cooling capability? Trying to keep this baby alive for many years.
(I'm at 100km .. so I guess 65,000 miles on the truck)  :B:
 
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