Question about Transfer Case

[khass0410]

There may already be a thread for this but theres somewhere like 176 pages. How do you know if your Transfer Case is working good? What do I need to do to maintenance it? Also Your differentials. Where do I get my specs for my jeep all I know is I have a 75 CJ5 with a AMC 258 i6 / 4.2l ....Don't know gear ratio what kind of Transmission , Transfer Case , differentials Dana 44 ?? Anyone that can help thanks....I'm a newbie to the 4wd's.

Thanks

 

[Saddle Tramp]

If stock you should have a T-14 and a Dana 20 behind the AMC I6 with a Dana 30 front and a Dana 44 rear. Most likely the gears in the differentials are 3.73. Again this assumes everything is OEM. If the jeep is a new to you, I would change the fluids in all of the boxes and diffs as who knows with what or when they were last changed. Also water and dirt can enter through the vents and cause problems if left alone.

What comes out when drained may tell you if there is a problem but not always. Any metal or metallic flakes in the fluid of course is a bad thing as is milky, or dark, burnt fluid. Also drips or the indications of leaks on the boxes or around the pinion gear yoke or at the end of the axle tubes near the brakes can also be a clue; at least it is an indication of seal problem that may need attention.

Further, visual inspection of the u-joints at the yokes and drivelines is a good idea too and look for excessive play in the axles and drivelines. Jack up the front, grab the top and bottom of the tire and try to lift it up and down to see if you have much play. If so the ball joints may need attention or more. Use your ears and listen for squeaks. Crawl under the jeep and try to wiggle the drive lines. If you hear squeaks, feel rough spots or have excessive play it is again not good. Take the jeep to a professional for their opinion when in doubt or just rebuild it before you have a problem if the piggy bank allows and start off fresh.

I’m sure others will add more but this will get you started.

 

[Incommando]

As mentioned above many 37 year old jeeps are no longer stock, even those that may appear so.

The only way to be 100% sure about your axle ratios is to pull the covers and count the splines on the ring gear and divide them by the number of splines on the pinion. Doing so will also enable you to change the diff. oil as part of your maintenance cycle and, again as mentioned above, inspect the fluid.

The Dana 20 Transfer Case is one of the best ever made and is pretty indestructible. Drain the fluid and look at it. Be warned: it and the used axle gear oil will stink. Replace the fluid.

You can easily test low range by engaging it. The change in the gear ratio will be very obvious. If you can't put the jeep on a lift to test the Transfer Case you can do it by having a driver and someone to observe the front axles & driveshaft. With the front hubs unlocked and the Transfer Case in 2HI the front driveshaft should not move when the vehicle does. With the Transfer Case in 4hi or 4lo but the hubs unlocked the front driveshaft should turn but the front tires will not have power. With the Transfer Case in 4hi or 4lo and the hubs locked the front drive shaft will turn and the front wheels will have power. This is much easier with the vehicle on a lift or at least with both all four tires securely off of the ground with at least 4 jack stands. To check that the front tires are actually getting powered with them on the ground you will have to be on a surface slick enough to allow the tires to spin.

Remember that most axles have "open" differentials and that even when powered only one wheel on either axle set will turn under power. The only time that both wheels will turn under power is if the vehicle has some sort of locking differential (locker) or a Limited slip differential (commonly referred to as an LSD or a "posi," which is the GM term for their LSD that is applied to other versions, too. Jeep called it Trac-lok.)

http://www.jeep-cj.com/forums/f2/amc-20-dana-35-a-15854/

Go to post #2 on the above link and compare the shape of your diff cover to the chart to identify what you have. The OEM axles should be a Dana 30 front and Dana 44 rear. Your front should have a "30" and the rear a "44" cast in the webbing by the diff cover. Sometimes age renders these next to unreadable, though.

 

[khass0410]

Cool, Thanks y'all....Took the cover off of my rear diff. today cleaned it up with some brakecleen about to post another thread with pix and of course questions.

 

[khass0410]

Do I put gear oil in the Transfer Case and Transmission when I do the change? or ATF?

 

[Incommando]

Gear oil