07-04-2024, 07:36 PM | #1 |
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Upgrading to POSI
My 68 C10 will eventually have a 700r4 installed and the 3.07 open will be replaced with a 3.42 or 3.73 POSI. Have not made up my mind on the ratio yet.
What units are you guys using for your POSI? I have been told the GM80 is good and bad and there are others as well. Would like to get your opinions. Thanks!
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RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234 |
07-04-2024, 08:43 PM | #2 |
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Re: Upgrading to POSI
Eaton is the stock unit, and they are stout and rebuildable. I've had good luck with Auburn. I prefer 3.73 in a halfton truck.
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07-04-2024, 08:43 PM | #3 |
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Re: Upgrading to POSI
I like and use Detroit Tru Trac. No posi friction lube needed.
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07-04-2024, 08:45 PM | #4 |
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Re: Upgrading to POSI
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07-04-2024, 11:50 PM | #5 |
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Re: Upgrading to POSI
I also have a Tru Trac. I love it.
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07-05-2024, 08:38 AM | #6 |
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Re: Upgrading to POSI
For street use you, can't beat the Eaton TrueTrac,
I have them in all 3 of my trucks
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07-05-2024, 10:09 AM | #7 |
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Re: Upgrading to POSI
I have a 700r4 with an Auburn 3.73, haven't put a lot of miles on it but its fun.
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07-05-2024, 12:07 PM | #8 |
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Re: Upgrading to POSI
I will look into the Eaton TrueTrac. I plan on driving and using this truck maybe even a roadtrip or two
Thanks!
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RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234 |
07-05-2024, 12:51 PM | #9 |
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Re: Upgrading to POSI
Did the i6 equipped trucks have 3.73 from the factory in the 12bolt?
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07-05-2024, 01:14 PM | #10 |
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Re: Upgrading to POSI
Mine doesn't, but it's a 292 not a 250. I have 4.11s
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07-05-2024, 02:32 PM | #11 |
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Re: Upgrading to POSI
the standard gear seems to be 3:73 in the I6 1/2 tons.
Get Eaton vs Auburn LS diff. Or the Eaton TruTrack. My $.02 is I prefer the LS vs TruTrack. 700R4 has a VERY low 1st gear so I would go 3:42's to keep the Fwy RPM's down. |
07-05-2024, 03:04 PM | #12 |
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Re: Upgrading to POSI
.
700r4 here with 3.73 Eaton posi. The low 1st gear helps it get off the line quick and the rear gear keeps the RPMs in check at speed. 2000 RPM = ~75MPH, 2150RPM = ~80MPH. Hth, -Kevin
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67 C10 fleet fuel injected '70 402, 700r4, 3.73 posi 07 335 sport turbo 6sp 94 Trans Am GT LT1 6sp posi -- sold after 22yrs 99 540 sport V8 6sp -- sold 73 240z L24 4sp -- given to friend 68 C10 step 350/350 3.73 open -- sold |
07-05-2024, 05:56 PM | #13 |
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Re: Upgrading to POSI
I have a 2001 gmc sierra 1/2 ton with 3.42s. 80 mph is 2100 rpm. Roadtrip cruiser
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RIP to my son Dylan. 5/17/2002 - 8/18/2018 If you want to know more about rare forms of pediatric cancer or if you want to help fund pediatric cancer research, please check out the website for the non-profit I started. https://slothforpedcancer.org 68 build thread http://67-72chevytrucks.com/vboard/s...d.php?t=223234 |
07-05-2024, 09:18 PM | #14 |
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Re: Upgrading to POSI
My '68 C/10 came with a 292 L6 and 3.73 rear.
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07-05-2024, 10:35 PM | #15 |
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Re: Upgrading to POSI
I’ll verify next time I have the truck in the air but if it already had 3.73s that would be awesome and one less thing to worry about.
Can anyone elaborate on the Eaton LS vs Tru Track? What is the cost difference? I want to be sure that when I pop that clutch both tires go up in smoke for many years to come on the street.
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