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Discussion Starter #1
Greetings. I am just a few days away from taking home a new to me 2005 Silverado 2500 HD with the 6.6L Duramax diesel power-plant. This will be my second Silverado but first with the diesel. I had the truck looked over by a mechanic who gave it a good bill of health and we took it for a good test drive, also turned out well. We were surprised that the ride was as good as or better than the previous Silverado 1500.

I have looked up most of the RPO's listed in the glove box but haven't found definitions for a few. If anyone knows what they refer to please let me know: 1SZ, 6GL, 69I, 7GL, M74, PDN, R97, TQ3, UB1, UQ7, and U2K. I am puzzled by the M74 as I have found some references that seem to indicate this means the truck was built with an Allison LCT 1000 5 speed automatic transmission however the shifter just indicates "P R N D 3 2 1". Am I missing something? None of the truck badging indicates an Allison transmission.

Anyway, I am looking forward to reading about the Duramax.
 

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Welcome to the DF!!
 

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Discussion Starter #4 (Edited)
. . . nice truck man how many miles?
Well, I don't have a lot of money so I had to go with a well "broken in" vehicle. This one has 190K but runs with a lot of heart and has a good record.

I wasn't aware all had Allison, thought I had read that some had another GM brand. Why do they badge some with Allison and some others not? What about the 5 speed for the M74 RPO? Is this a 5 speed with some kind of automatic overdrive while in "D"rive?

Thanks both for the welcome.
 

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Welcome to the DF!

Did you buy the truck from Carl Black in Kennesaw?
 

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Welcome to the DF. Good luck with your truck
 

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is your avatar a blackberry barcode lol
 

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Discussion Starter #9
. . . if you need anything check with georgia diesel.
I'll be sure to look them up if I find the need and have the money.

Did you buy the truck from Carl Black in Kennesaw?
No, from a small corner lot outside the southwest burbs.

is your avatar a blackberry barcode lol
Not familiar with bb stuff but it might be. It's actually known as a QR code. It's like a bar code in that it contains data. Ask a friend with an Android phone or maybe an iPhone to read it.

Should I post my RPO questions in another part of this forum?

Can anybody guide me to the photo galleries and how I can set up one of the three indicated as a feature of becoming a member?

Thanks again for the greetings.
 

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welcome to the DF
 

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Discussion Starter #11
Found the gallery. Haven't figured out how to embed gallery pics into messages though, it's late.

Here's a couple of pics. Pretty much plain but I can't wait to pick it up.



 

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Well, I don't have a lot of money so I had to go with a well "broken in" vehicle. This one has 190K but runs with a lot of heart and has a good record.

I wasn't aware all had Allison, thought I had read that some had another GM brand. Why do they badge some with Allison and some others not? What about the 5 speed for the M74 RPO? Is this a 5 speed with some kind of automatic overdrive while in "D"rive?

Thanks both for the welcome.
Yes it is an automatic overdrive and on the end of the gear shift leaver is a button....push and hold turns the overdrive off and tap the button turns the tow/haul mode on!! And welcome:drink
 

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And the 06 and later models had the duramax/allison badge on the side and the earlier models just had duramax diesal on the side
 

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Discussion Starter #16
Yes it is an automatic overdrive and on the end of the gear shift leaver is a button . . .
That's good to know. In researching this I read a forum post (different site) where a guy was griping about not being able to keep his 2001 Silverado from downshifting out of overdrive while towing his fiver and there was no way to keep it from going into fifth. Either he didn't RTFM or that year they didn't have the override button. I even found instructions for a mod for '99 - '02 Silverado's with the Allison transmission to create an override button.

And the 06 and later models had the duramax/allison badge on the side and the earlier models just had duramax diesal on the side
That solves that, thanks.

. . . Where is South of Atlanta? . . . If I can ever be of assistance, don't hesitate to ask. . .
We're newly relocated to Fayetteville. Thanks for the offer, I'll keep you in mind. You just may get a message from me here seeing as I have just purchased a well worked truck. I guess I get to do a little work right at the get-go. While test driving I noticed it said the fuel filter had 0 hours life left. The mechanic we consulted said it was a little work to do but I could do it myself nonetheless. And, I'm gonna need tires in the next few months. I have set aside a bit of money for this, maybe you can tell me where the best deals can be had around here.
__________________________________

Another question about the RPO's. I found that SAF indicates something like "LOCK - SPARE TIER, HOIST SHAFT". Does that mean there's some kind of lock securing the spare tire? If it is there (if the original owner didn't take it before trading it in) does it use the ignition key or am I looking at possibly having to cut this thing off so I have access to the spare tire?

Thanks all for the welcome and good info. I'll probably be able to drive the beast home as early as Monday but probably Tuesday.
 

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Discussion Starter #18

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All the years have the allison! Some have a the five speed and some have to six speed. From '01 to '05 they are the five speed and from '06 to current they are six speed. If you get underneath your duramax the tranny oil pan says allison on it! Welcome to DF!!
 

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That's good to know. In researching this I read a forum post (different site) where a guy was griping about not being able to keep his 2001 Silverado from downshifting out of overdrive while towing his fiver and there was no way to keep it from going into fifth. Either he didn't RTFM or that year they didn't have the override button. I even found instructions for a mod for '99 - '02 Silverado's with the Allison transmission to create an override button.

That solves that, thanks.

We're newly relocated to Fayetteville. Thanks for the offer, I'll keep you in mind. You just may get a message from me here seeing as I have just purchased a well worked truck. I guess I get to do a little work right at the get-go. While test driving I noticed it said the fuel filter had 0 hours life left. The mechanic we consulted said it was a little work to do but I could do it myself nonetheless. And, I'm gonna need tires in the next few months. I have set aside a bit of money for this, maybe you can tell me where the best deals can be had around here.
__________________________________

Another question about the RPO's. I found that SAF indicates something like "LOCK - SPARE TIER, HOIST SHAFT". Does that mean there's some kind of lock securing the spare tire? If it is there (if the original owner didn't take it before trading it in) does it use the ignition key or am I looking at possibly having to cut this thing off so I have access to the spare tire?

Thanks all for the welcome and good info. I'll probably be able to drive the beast home as early as Monday but probably Tuesday.
First thing I would do it get all the fluids switched out and put on to your own schedule especially since you don't know when they were done. Fuel filters are very easy to do and several of the vendors here offer great deals on them.

Look forward to hearing from you. Take care,
 
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