i changed the fluid a while back and i cant seem to find the tags anymore. but at 70 im a hair shy of 2000 rpm. any ideas. also, is it a sterling read or a dana 60? how do i tell? thanks dan

 

i have 4.10's and get 2500 rpm's at 73mph so id guess you probably have somthing like 3.73's im sure somone with your same gears will chime in and correct or confirm for you. but you defently dont have 4.10's

 

i have 3:55s and i run just under 2000 rps at 70 mph

 

thanks alot guys, dan

 

Yup sounds like 3.55's to me

-Robb

 

any advice on wether its a dana 60 or a sterling?

 

I do believe we have Ford 10.25" Rear's... check this link.
http://www.4wheelnoffroad.com/axle.html#Ford

 

all of the 250\350's have 10.25 diff's out back and dana's upfront, the 250's have dana 50 and the 350 has a dana 60

 

you have 3.55. thats what i have and im right at 2000 doing 72mph. i think the only options on these trucks were 4.10 or 3.55 the 3.73 didn't come till the new body style

 

Is there a way to tell which gears you have by a VIN number? Curious about the truck I'm thinking of buying.

 

No but you can from the vin tag on the B-pillar (door jam near latch bolt)
c5 is 4.10 limited slip
c9 is 3.55 LS
35 is 4.10 open
39 is 3.55 open

 

Wish mine said c9... nope 39 hate my open diff...Need 4x4 every time i'm in a bit of ice or snow or sand...
Don't have the $$$ for a locker...

-Robb

 

i wish i had a split rear end in my truck i love the 4.10's towing 5th gear 75mph my truck is like a freight train, passing semi's like there not even moving climing grades or agenst the wind, but when im unloaded i wish i had 3.55's

 

a friend of mine has a ls dana 60. is this a direct replacement? i already intend om putting a dana 60 up front. thanks, dan

 

no it wouldn't be direct fit that i know of. also wouldn't be an upgrade either