Dana 300 Transfer Case Parts for Jeep CJ7

Why the Dana 300 in the late CJ7 needs wear parts.

From model year 1980 the Dana 300 replaced the Dana 20 in the CJ7 – a gear-driven cast iron unit with a much lower 2.62:1 crawl ratio, still regarded as the strongest transfer case ever fitted to a CJ. Strong does not mean wear-free, though. As on its predecessor, the intermediate shaft runs on loose needle rollers between shaft and gear: once they migrate or the thrust washers wear thin, play develops and shows up as a hum under load. The tapered roller bearings on the input and output shafts lose their preload over the decades simply because the shims were never reset. At the same time the seals on the shaft outputs and the shifter shaft harden, gear oil escapes and the oil level drops unnoticed. Worn shift linkage bushings finally cause the low range to jump out under load.

The parts that belong on the bench

• Overhaul and bearing kits: For a full rebuild the Dana 300 overhaul master kit combines bearings, gaskets and seals; if you are only renewing the bearings, the bearing kit including shims and needle bearing is the one to pick. A small parts repair kit rounds it off.
• Shafts and gears: With scoring or worn teeth, replace the front output shaft or the input gear; the front output gear as well as intermediate shaft, spacer and thrust washer are available individually too.
• Bearings and shims: For the correct preload you will find the input shaft bearing with the matching shim kit; the front output shaft bearing, the rear needle bearing plus cups and shims for the rear output complete the set.
• Gaskets and oil seals: The gasket and oil seal kit covers the standard jobs; individually you can get the output shaft seal for front and rear, the input seal to the T176/T177, the shift rod seal, the housing gasket and the intermediate shaft seal.
• Shift linkage: When the low range jumps out, shifter shaft and linkage bushing are usually the cause; the shifter boot for T4 and T5 transmissions is stocked alongside the T176/T177 version, plus shift knob with pattern insert, shift fork pad, poppet ball and spring.
• Driveline connection and mounting: On the output side the yoke kit connects the case to the propeller shaft, joined by u-joint straps, pinion nut and lock washer; against vibration the transmission mounting insulator, its stud and the polyurethane torque arm bushings do the job.

Crown, Dana Spicer, Omix and Daystar in this category.

The bulk of this range comes from Crown Automotive – from a single shift fork pad to the complete overhaul kit, the US manufacturer has kept the late CJ models supplied for decades. Yokes, u-joint straps and pinion nuts come from Dana Spicer, original equipment manufacturer of the case itself. The dual shift linkage boot is made by Omix, the polyurethane mounts by Daystar – American production throughout, with the dimensional accuracy that reassembly depends on.

Unsure about preload and shims?

On the Dana 300 the bearing preload decides how long the rebuild lasts: shim thickness at the input and output shafts has to match the measured play, and the torque figures at housing and yoke are tightly specified. Ask us beforehand – we are glad to advise on compatibility, assembly sequence and torque values. Shipping goes out from stock in Germany, usually on the next working day after payment.