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-   -   Rear differential help please (https://67-72chevytrucks.com/vboard/showthread.php?t=810521)

Woodnears 08-13-2020 07:56 PM

Rear differential help please
 
I am asking for your help or basically telling me what I need to do to get the most out of this truck. 68 C10, currently has a 4.8 ls engine backed with a 4l60e. The rear axle is stock with 373 gears. I am running 22x9 wheels and Iím curious if I need to consider changing gear ratios but have no experience with this area.
Anyone else running a similar setup that could give some advice? Itís obviously not a speed demon but I do want a quality built rearend that will handle any future upgrades. Am I asking too much?

kwmech 08-13-2020 08:45 PM

Re: Rear differential help please
 
I wouldn't bother with the 3.73s and the overdrive

Woodnears 08-13-2020 08:50 PM

Re: Rear differential help please
 
It seems a little bogged down. What would you bother with?

mongocanfly 08-13-2020 08:58 PM

Re: Rear differential help please
 
What size tires are you running?
The 4.8 is no powerhouse, but you may need a good tune...did you run it on a chassis dyno after your swap?
The cost to swap gears isnt gonna be cheap, but 373s should be fine with a 4l60e..unless you have really tall tires

Woodnears 08-13-2020 09:15 PM

Re: Rear differential help please
 
Tire and wheel combo are roughly 31Ē

geezer#99 08-13-2020 09:22 PM

Re: Rear differential help please
 
You’re running about 2 grand at 70 mph.
Are you carbed or injected?

mongocanfly 08-13-2020 09:38 PM

Re: Rear differential help please
 
Heres a rpm calc to help you out...
http://www.csgnetwork.com/multirpmcalc.html

Your turning a little over 1800rpm at 65mph..with a 31in tire and a .7 od with 3.73s
I try to set mine up to turn 2k at 65mph..seems to be the sweet spot for me.
If you were starting from scratch I'd say 4.10s...since your already 3.73s I wouldnt waste the money to swap it
But your 3.73s should be fine if you have a good tune..

Woodnears 08-13-2020 11:33 PM

Re: Rear differential help please
 
Thanks for the calculator link, thatís handy. This rearend is leaking anyway and needs new seals, bearings, axle. The Way I see it needs rebuilt anyway. Is it worth going to limited slip?

mongocanfly 08-14-2020 08:40 AM

Re: Rear differential help please
 
In my book,It's always beneficial to add a locker...the Eaton trutrac is one of the best....

SB'72 08-14-2020 10:51 AM

Re: Rear differential help please
 
Trutrac is a great unit

Ziegelsteinfaust 08-14-2020 06:20 PM

Re: Rear differential help please
 
On my 07 gmc with a 4.8 I ran 4.56, but if I had it to do over 4.11's or 4.33's would of been my choice. I had stock steel 17's though.

The 4.56's were not bad, and suited the truck well. Just ceuising over 75, a.d it was always wanting to down shift.

b454rat 08-14-2020 07:40 PM

Re: Rear differential help please
 
Plus those wheels ain't helping any. I have 20s on my tundra and are HEAVY.

gmc684x4 08-15-2020 12:16 PM

Re: Rear differential help please
 
Why such a tall tire on a c10 i can see taller tires on a k10 ?
C10 tire hits the range of 28.5 inchs tall usually

Woodnears 08-15-2020 01:22 PM

Re: Rear differential help please
 
1 Attachment(s)
Hereís a pic of the truck! Think Iím gonna try a trutrac, Iíve heard a lot of good things about them.


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