Duramax Questions

[Ginger]

Been looking at replacing both my trucks with a newer duramax, and i have a few questions.

i know that 06-07 lbz is the best motor. LLY's have overheating problems. Is it that common for the lly to overheat?

biggest question i have, i know they didnt put the 6 speed allison in until 06. Is it a big differance between the 6 speed and the 5 speed?

I found a good deal on a 05 with low mileage, but after reading some, i get worried.

Anything else to watch for besides the normal GM truck stuff?

thanks.

 

[Molly]

My friend has an LLY and ragrets not getting an lbz for the six speed. On the highway he's always over 2k and I don't think I am until 90 but I can't quite remember


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[linden]

I had no real issues with my 5 speed in my lb7 and was runny the ppe level 4 160 tune. I didn't baby it but I also wasn't doing boosted launches. My brother has a 6 speed there is more aftermarket options for them and I think they are supposed to get better economy. No experience with a lly though

 

[a-fuso]

LLY overheating was an early production issue. If the truck has lasted this long most likely it has been updated to the lbz mouthpiece and not had any issues.

The 5 speed trans is identical except it has 1 over drive ratio instead of 2, supposed to be a little stronger, but 5 speed can also be converted to 6 spd during a rebuild.
lly's are also known for injectors going out, just a lot easier to replace than the lb7.

 

[marc]

if your not a mechanical moron an lly is a good truck.

they have a few little quirks but are easily solvable.

also they have the biggest of the stock turbo's so in theory if it is tuned would make the most hp compared to the lb7 lbz and lmm.

the 5 speed is an alright tranny its a little weaker then the 6 speed and as previously mentioned the rpm's are quite a bit higher then the 6 speed but besides that its pretty good.