PROBLEM SOLVED at cross roads with rear gear ratio choice in 5.3 swap to truck
#1
Launching!
Thread Starter
PROBLEM SOLVED at cross roads with rear gear ratio choice in 5.3 swap to truck
read down few posts . found 4.10 gear axle bolt in for truck.
SPECS : 1985 chevy short bed 2wd / 03 5.3-4l60e combo / 2.5" drop front and rear with 275/60/15 ( 28" tall ) tires planed .
this truck will be used for daily driver use / some play toy / 1-2 trips to drag strip if lucky / pull small trailer with atv or what ever.
the truck was orignal 4.3 v6 th350 and 2.73 gear open.
since the truck is getting full frame off reso mod i figured time to change the rear ratio up .
i have another 10 bolt from same style truck with 3.08 open. and i have picked up a ford 9" 31 spline truck axle to swap in was to be 3.50 gear but turns out 2.72 ratio guy did say he would make it right by me.
well today he calls me up and has another 3rd member with 3.25 ratio open but 28 spline from late 60's early 70's truck axle. ya i could swap spider gears out for the 31 spline mabye as some say the older 28 spline carriers wont fit the 31 spline shafts in them.
both axle choices need brakes full rebuilt so same money in that department. and if ford 9" can swap on 8.8 truck axle disk brakes stupid easy from what i have read. so money best spent on 1 or other in this department.
i was kind of hoping for good all around 3.50 like he was to have sold me . 65 mph it was going to get me 2k rpm basicly .
also planned on eaton true trac helical gear posi at some point in 9" if i went that route.
what combo would you run if it was you ?
i live in upstate ny lots of smaller hills and flat land good mix of it all.
thanks for any help guys as i am new to ls swaps and 2wd my self. ( i am 4x4 big truck guy mostly ) and you know what these ls motors like for rpm ranges.
SPECS : 1985 chevy short bed 2wd / 03 5.3-4l60e combo / 2.5" drop front and rear with 275/60/15 ( 28" tall ) tires planed .
this truck will be used for daily driver use / some play toy / 1-2 trips to drag strip if lucky / pull small trailer with atv or what ever.
the truck was orignal 4.3 v6 th350 and 2.73 gear open.
since the truck is getting full frame off reso mod i figured time to change the rear ratio up .
i have another 10 bolt from same style truck with 3.08 open. and i have picked up a ford 9" 31 spline truck axle to swap in was to be 3.50 gear but turns out 2.72 ratio guy did say he would make it right by me.
well today he calls me up and has another 3rd member with 3.25 ratio open but 28 spline from late 60's early 70's truck axle. ya i could swap spider gears out for the 31 spline mabye as some say the older 28 spline carriers wont fit the 31 spline shafts in them.
both axle choices need brakes full rebuilt so same money in that department. and if ford 9" can swap on 8.8 truck axle disk brakes stupid easy from what i have read. so money best spent on 1 or other in this department.
i was kind of hoping for good all around 3.50 like he was to have sold me . 65 mph it was going to get me 2k rpm basicly .
also planned on eaton true trac helical gear posi at some point in 9" if i went that route.
what combo would you run if it was you ?
i live in upstate ny lots of smaller hills and flat land good mix of it all.
thanks for any help guys as i am new to ls swaps and 2wd my self. ( i am 4x4 big truck guy mostly ) and you know what these ls motors like for rpm ranges.
Last edited by sweetk30; 07-22-2012 at 01:15 PM.
#2
TECH Resident
Every car I have ever had I put 4.10s in, exept one truck I had with 4.56s. I personally wouldn't mess with anything under 4.10, but a lot of guys feel differently. I can tell you though, that with four gears, even with 4.10s, you won't be much above 2k at highway speed.
That being said...I still have stock gears in my swap project. Gotta put the money into getting it running at the moment.
That being said...I still have stock gears in my swap project. Gotta put the money into getting it running at the moment.
#4
TECH Fanatic
I would run 3.50 or 3.73 since your not going to use it to tow heavy. That will still give you some ice RPM's at cruise and will help when towing to keep it from hunting for gears up a small hill.
#5
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I've got 4:10s in my VMax, although I have 20s. I had 16s and 3:73s on my old 99 with a 5.3. With both trucks revving was never an issue. If it were me I'd watch the classifieds on Performance Trucks and find a set of cheap 3:73s when someone's swapping to a lower gear.
#6
Launching!
Thread Starter
well got my money back on the 9" rear. thats out for now since i am so close on the budget and it wasnt the ratio i needed.
did some digging around and called up a old buddy of mine. he had a few 1/2 ton rears in his pile of axles. found a 12 bolt with 6 lug and 4.10 gears. then he remebered the pickup trailer outback of the shop has a 5 lug rear. so we pulled the cover and found good clean oil and even 4.10 gears in it also.
so for 100 bucks i get a bolt in clean up brakes and seal the rear back up 4.10 12 bolt rear. not bad at all i think.
just a little more gear than i wanted but i can deal with it over 3.08 i had to use otherwise.
thanks for the input guys
did some digging around and called up a old buddy of mine. he had a few 1/2 ton rears in his pile of axles. found a 12 bolt with 6 lug and 4.10 gears. then he remebered the pickup trailer outback of the shop has a 5 lug rear. so we pulled the cover and found good clean oil and even 4.10 gears in it also.
so for 100 bucks i get a bolt in clean up brakes and seal the rear back up 4.10 12 bolt rear. not bad at all i think.
just a little more gear than i wanted but i can deal with it over 3.08 i had to use otherwise.
thanks for the input guys