Novak Conversions Jeep Wrangler TJ engine mounts

Anybody able to decode a VIN with axle ratios?

Gilaguy23

TJ Enthusiast
Original poster
Joined
Sep 21, 2021
Messages
767
Location
TJ north
Trying to work a purchase on a 97/4.0/auto many hours away. Owner does not know what rear axle or ratio's it has. Its running 33's and It a deal breaker probably having to regear if i ts 3.07's. The basic decoder does not cover this info. Recon you'd have to work at a dealer or??
Thank you for any help.
 
All he has to do is crawl under it and read the tags on the axles assuming they are stock.

He can also report back on the engine rpm at a specific speed after torque converter lockup. This will allow the axle gear ratio to be closely calculated with an approximation of the 33's actual rolling diameter.
 
The VIN information and the metal tag under the differential cover bolts may be incorrect if a previous owner changed the gears.
To approximate the installed gear ratio you can jack up the rear of the Jeep, place a mark on the driveshaft and the tire, spin one of the tires and compare how many revolutions of the driveshaft to revolutions of the tire.
 
My suggestion would be to not worry about the gearing too much. Depending on your purpose for this jeep, you could either put the tires back to stock to match the stock gearing if that’s what it has, or you could limp it along like the current owner has done and look for a set of 4 cylinder axles to swap in eventually. If you like and want the Jeep, I wouldn’t let the gearing stand in the way. And who knows, maybe it is regeared to a better ratio.
 
Novak Conversions Jeep Wrangler TJ engine mounts