Dana 300 T-case

[Roy Gardner]

Hey guys first day here...... Looking for some professional help, although I am an ase certified tech.... I DON'T KNOW IT ALL.... LOL.
I have a 1981 Jeep CJ7 inline 6, SR4 Transmission , Dana 300 t-case. Just did a reseal on the Transmission and t-case to eliminate some leaks........ NEW concern...... In 4 HI In third and fourth gear I have a ratcheting noise coming from the t-case especially on decel. If I shift the case from 4 to 2 and back into 4 sometimes it is gone. Now when I did the re seal I removed a .002 shim from the fromt output drive to add a little more load on the bearings...... Something tells me that this is where my prob is.
Any thoughts?????

 

[JR74CJ5]

You know I haven't ever re-built one myself. I seen this earlier and was hoping another "builder" might have better info for you.

I would say if it didn't do it before, just leaked, and you took the spacer out, and now it does it, I would try correcting what you changed. I'm not sure if you'd need a new spacer / shim or re-use the one you took out etc, but i would do that.

Now again, I do not know squat about the Dana 300 , and have never fully re-built a Transfer Case as of yet, so what do I know!

oh and :ww: to the site! hope you stick around!


~Jr

 

[Roy Gardner]

Hey thanx for the welcome........ Ya know I'm actually not convinced it was there before...... I built this for a buddy of mine and he says its new..... I tested it forwards and backwards before I kicked it out.... 2Hi, 4 hi, 4lo..... evrything sounded awesome.... Right out of the box he took it wheelin up in the snow..... BIG SNOW... the kind where you air down.... Anyway he calls me and says it makes noise in 2HI in third and 4th but it went away..... He had his dog with him jumpnn around I suspected he bumped it inbetween shifts....????? Got it back today.... I drove the piss out of it and the only thing I have is a noise on decel in 4HI in third and fourth..... Maybe its there in first and second as well??? It has loud exhaust. I drove it again and again.... same thing.... If I push ahead on the shifter a bit all good. My diagnosis is a bent HI-LOW shift fork from trying to force it in gear...... I told him that and he says he never used 4HI...... HMMMMM. I see people looking at this post and have read previous post's.... and the answer is usually to replace...... I say run it..... My pockets are deep..... LMAO.....

 

[JR74CJ5]

now I assume its very difficult to hear and know it IS coming from the T-case if like you say it only happens (mostly) when in 4Hi/Lo First if you are on the pavement in 4 anything (hi/lo) in 3rd or 4th gear, at least in my 74 every things going to be making noise (including my hooker headers! ) Could be any part of the drivetrain making the noise... Is there a locker in the front end?

When you had the T-case apart did you see anything out of the ordinary internally to make you think the "snow trip" may have over worked any of the internals? Unless it's twin sicked with no interlock pins, I think it would be hard to screw it up by shifting... My pit bull has knocked my shifter into neutral while in motion before, but never between hi / lo 4...

Again I have a Dana 20 tcase, so maybe different on a 300?

I've had to yank hard on my shift knob a few times to try to get it in and out of gears (before twin stick-ing) and had never bent the shift forks on mine, BUT thats not to say any of that is impossible! I've already established my Limited knowledge on this subject! lol


~ Jr

 

[Roy Gardner]

No you make good points..... No locker in the front, single shifter... I hear the twin stick is better. Front to back.... 4lo, neutral, 2hi, 4hi. It was a thought, I thought maybe he could have pushed it one way or another.... Just a thought... this thing is makn me CREATIVE with ides. Anyway Ya.... 4 wheel on the black top could be all it is. Afterall, its not even what he was worried about... Noise in 2hi.... I got nadda. I am just tryn to rule out anything. I told him to run it... If it breaks or gets worse worry about it then. Its a pavement queen anyway so its not like hes gonna bah ha in 4hi anyway..... Thanx for the input... Im gonna send it out AGAIN and see what happens.....

 

[mtnwhlr]

4 wheel on the black top could be all it is.

Thats a BIG NONO.

 

[gert]

Your noise could be the pinion bearing on the rear axle, I had that problem if there is to much slack in the pinion to ring gear it will whine. I would grab the pinion yoke and shack it around to see if the bearing is wearing out.

 

[Roy Gardner]

GERT........ Ya know its always the simple things that kick ya in the ^*#!+..... I went out and checked this thing out as ITS STILL HERE.....
I did re-use the rear bearings, and races during the rebuild of the AMC20 ..... I tend to run my bearings on the tight side always.... I think my total pinion torque by itself was 28" pounds.... a tad high for used bearings I know but it usually works out ok for me. The seal is dry and the yoke is still firmly in place,.... HOWEVER I did find play in both rear shaft u-joints..... Not much but we all know it dont take much.
I consider myself a seasoned vetran when it comes to drivetrain but simply overlooked the obvious ( elephant in the room ). When I got the jeep it was already lifted, new driveshafts, and 2.73's pulling 35" tires. Came to me with ( no power, cant use fourth gear, clutch is shot ). I pointed out the obvious and made the upgrades...... Never checked the u-joints..... launching 35's with 2.73's makes sense the joints would be under severe stress huh? I am gonna replace both joints today and give it another try........ Almost positive thats it now..... Will post the outcome this afternoon. DAMN... There must be something with getting gray hair that makes you forget to check your basics......... Thanx ROY

 

[JR74CJ5]

I think my total pinion torque by itself was 28" pounds.... a tad high for used bearings I know but it usually works out ok for me.

I think I remember seeing it was supposed to be a lot higher than that...

 

[gert]

I think I remember seeing it was supposed to be a lot higher than that...

I think he is referring to the pinion bearing drag not the pinion nut torque which is significantly higher

 

[Roy Gardner]

Since the diff has a crush sleeve how else would you get bearing pre-load? The nut crushes the sleeve causing preload as far as I know.... Used bearings usually call for around 18 INCH pounds... The pinion by itself... no ring gear invloved.. I set mine @ 28 INch pounds. ( New bearing value ) Install ring gear and set back lash...... Am I missing something here??? This is an AMC20 .........Who knows what the nut torque is..... Preload is determined by rotational value of the pinion with an inch pound wrench on the nut while collapsing the sleeve. Any more than that will destroy the bearing in a rather short term.........

 

[JR74CJ5]

Since the diff has a crush sleeve how else would you get bearing pre-load? The nut crushes the sleeve causing preload as far as I know.... Used bearings usually call for around 18 INCH pounds... The pinion by itself... no ring gear invloved.. I set mine @ 28 INch pounds. ( New bearing value ) Install ring gear and set back lash...... Am I missing something here??? This is an AMC20 .........Who knows what the nut torque is..... Preload is determined by rotational value of the pinion with an inch pound wrench on the nut while collapsing the sleeve. Any more than that will destroy the bearing in a rather short term.........

I think I was mistaken on what you were talking about (happens a lot! lol)

The pinion nut holding the yoke on the outer most part of the pinion is what i thought you were discribing... I believe gert set me straight...

AMC 20 Pinion Nut Torque - JeepForum.com


~ Jr

 

[hagar]

It could be as simple as Transfer Case shift lever vibration.
The factory fix was a rubber shock bushing and flat washer pushed down over the shift lever where it engages the linkage.
I've heard some noisy ones where you would have thought something was wrong inside the Transmission /Transfer Case while driving.
I only mention this as you had mentioned slight shift lever pressure change the sound or makes it stop completely.
Did the shift lever have the rubber bushing and washer ?
Did it have the later lever shaft with lug nut on the threaded end (also factory)?
If not, you might try it.

 

[Roy Gardner]

Hey guys...... Found the problem...... Bad bearing. The front output shaft nose bearing is junk. Found play in the front yoke. Now I'm making the repair as a courtesy for my buddy. Since I was the last one in there. Must have done something wrong. I have not a clue but ( it is what it is )
Thanx for all the input and sorry for workn you guys over... EGG on my face fer sure. May as well rebuild the Transmission and engine..... Been through everything else lol.......UUUHHHHGGGG!!!!!!!!!

 

[gert]

yay