How do I know what gears?

[GusDaDog]

I have a Chrystler 8.25 rear end in my 1992 Laredo...how do I know what gears I have inside there? (4.0L 4x4 Automatic if it helps)

[ACE]

Well unless a previous owner has dicked with it, you will have 3.54 gears in there since you have the I6 and auto.

[PFunk242]

Would that be the same for a 92 w/ a 4.0 and auto?

Fenton Beech

[Yucca-Man]

Typically it should be. Look for a tag on the back of the diff cover that should include the gear ratio. Next time you change the gear oil of course you can look on the ring gear for the tooth count stamped into it.

[XJ-wrecks]

you can tell what gears you have by how many times your drive shaft turns in to every one full turn of the rear tire.

How to:
1. jack up the vehicle
2. use white chalk and mark the rear tire ( i mark it at the bottom pointing directly to the ground) - you can mark the ground to be more accurate.
3. use white chalk and mark the drive shaft (same as tire)
4. rotate the tire and count how many times the drive shaft rotates.

ex.
if the drive shaft rotates 4 times to every one complete turn of the tire
gears = 4:10 ( 4 to 1)

or:

if the drive shaft rotates 3 times to every 3/4 turn of the rear wheel
gears = 3:75 ( 3 to 3/4)

hope this helps!
rex

[JeepinAudiophile]

ex.
if the drive shaft rotates 4 times to every one complete turn of the tire
gears = 4:10 ( 4 to 1)

or:

if the drive shaft rotates 3 times to every 3/4 turn of the rear wheel
gears = 3:75 ( 3 to 3/4)

hope this helps!
rex
This info is not quite correct.... (if it were, then these two gears would yield the exact same end ratio, which we know is not correct)
4.10 means 4.10 rotations of the driveshaft to every 1 rotation of the wheels....
3.75 means 3.75 roations of the driveshaft for every 1 rotation of the wheels... and so on...

Good Luck with checking the gearing....

[Yucca-Man]

you can tell what gears you have by how many times your drive shaft turns in to every one full turn of the rear tire.

How to:
1. jack up the vehicle
2. use white chalk and mark the rear tire ( i mark it at the bottom pointing directly to the ground) - you can mark the ground to be more accurate.
3. use white chalk and mark the drive shaft (same as tire)
4. rotate the tire and count how many times the drive shaft rotates.

ex.
if the drive shaft rotates 4 times to every one complete turn of the tire
gears = 4:10 ( 4 to 1)

or:

if the drive shaft rotates 3 times to every 3/4 turn of the rear wheel
gears = 3:75 ( 3 to 3/4)

hope this helps!
rexGood theory, bad math. The driveshaft turning 4 times to one tire rotation = 4.0:1 gearing, which is exactly the same ratio as 3 driveshaft turns to 3/4 of a wheel rotation.

Always turn multiple times just to be clear anyway; 35 1/2 turns of the driveshaft to 10 wheel turns makes a 3.55 ratio

[JeepinAudiophile]

HA!!! Beat ya to it!!!

[Tom R.]

Would that be the same for a 92 w/ a 4.0 and auto?

Fenton Beech
Yes, without a doubt.

[XJ-wrecks]

hey... gimme some credit. i was pretty close for only doing it twice. :doh:

and the last time was about 10 years ago.

ty SGT Peters

Rex