Jack it up, put it in neutral, spin the driveshaft...count how many times you have to turn the driveshaft for the wheels to make a single rotation. If it's about 3.5 driveshaft rotations you have 3.55's, if it's about 4 driveshaft rotations you have 3.92's. That's about the most promising way to KNOW what gears are in it.
Jack it up, put it in neutral, spin the driveshaft...count how many times you have to turn the driveshaft for the wheels to make a single rotation. If it's about 3.5 driveshaft rotations you have 3.55's, if it's about 4 driveshaft rotations you have 3.92's. That's about the most promising way to KNOW what gears are in it.
Wow. How about just opening the glove box and looking at the sticker? Seems a little easier to me.
Jack it up, put it in neutral, spin the driveshaft...count how many times you have to turn the driveshaft for the wheels to make a single rotation. If it's about 3.5 driveshaft rotations you have 3.55's, if it's about 4 driveshaft rotations you have 3.92's. That's about the most promising way to KNOW what gears are in it.
i thought this only worked if you had a spool also
On the back differential cover there are bolts that hold the cover on. If you look at these bolts there will be a small brass dirty tag on a blot (like a washer). It is usually located on the upper left bolt (drivers side).
If it says 3.9 then it is 3:92 and if it says 3.5 then it's 3:55
This tag is from the rear axle of a 1999 Dodge Durango. The tag reads 3.5, if you look at a 1999 Durango axle gear ratio table, you will see that the 3.5 corresponds to a 3.55 gear ratio.
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Quote:
Originally Posted by rebelboy
bet your motor aint as big as your mouth is.
I don't take sides.....I hate everyone equally.
Last edited by hydrashocker; 08-09-2009 at 08:36 PM.
request a build sheet for your truck. should take a day or 2 and up to a week to get it though, be something to keep for future repairs upgrades ext...
I just got my build sheet from that link above and it states that I have 3.92 gears, tow pkg, aux tranny cooler, power steering cooler, heavy duty engine cooling(?), and anti spin differential rear axle.
I looked on the rear diff and there is a tag for 3.5 unless I misread it?
I'm running 31x10.5x15 bfg at's and @ 70 mph my rpms hover 2100rpm. What are your rpms for various "confirmed" gear ratios with 31" tires??? i'll recheck in the morning.
sorry to get off topic, but I was also wondering:
is the anti spin diff the same as a limited slip?
heavy duty cooling--when i am in 100* weather AC running and it's a lot of stop n go traffic my truck hits 210* or a lil higher. Do you think I have a cooling problem or does this seem normal? can i install a 180* tstat with no ill effects-not saying to fix my problem, but can i install one to help my truck run cooler? how will it afffect mileage-if any? what else can i do to help keep the temps down?
thanks
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99 D SLT 4x4, 5.9, K&N drop in filter, Bilsteins, Magnaflow Dual Exhaust, 31" BFG All Terrains, White Night back up lights for now.
what gears?
