Driveshafts

[GRAT]

My 79 Chero has a knocking sound and a vibration when cruising at freeway speeds. The noice is loudest at about 40 mph. The u joints are new on both shafts, the flex plate bolts are tight and I am losing fluid somewhere.

Could I have a bad tranny pump or tranny seal, the front drive shaft has more play the the rear shaft when the shaft is twisted.


Any suggestions on the best way to diagnose ?

Thanks in advance fellow Jeepers.



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79 Chero WT/ TH400 /QT /360 /3" Dynomax / K&N

78 Chero WT 360 TH400

[JeepFreak]

Well I may be way off here but these are the exact symtems mine gave before it blew the transfer case chain. I would get a loud knock every once in awhile and a slight vibration. Granted I have a NP229 on mine but never the less this is what happened to me. Lucky for me I took of the front drive shaft and drove it anyway. http://www.ifsja.org/ubb/smile.gif This would not be a good thing for you with a BW 1339(QT).

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JeepFreak

[This message has been edited by JeepFreak (edited December 01, 2000).]

[GRAT]

Jeepfreak,


Would the noise intensify after freeway driving ?

I ordered fluid today and I will check the chain.


Thanks

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79 Chero WT/ TH400 /QT /360 /3" Dynomax / K&N

78 Chero WT 360 TH400

[JeepFreak]

Mine did get worse after highway driving. It didn't seem to make as much noise untill I got going. I didn't blow mine on the highway though. I did it being stupid in the mud but it was making the noise real bad before that. Mine would pop real bad in reverse. Like I said they are two different cases but both have chains that seemed to break pretty easy. I was lucky with mine cause I can take the front shaft off to hobble home. My vibration got a little worse to but wasn't noticable on the highway. Mostly at 40 to 50.

Maybe some of the other guys that have had chain trouble with the QT can add some info on this.

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JeepFreak



[This message has been edited by JeepFreak (edited December 01, 2000).]

[joe]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JeepFreak:
Lucky for me I took of the front drive shaft and drove it anyway. http://www.ifsja.org/ubb/smile.gif This would not be a good thing for you with a BW 1339(QT).

<HR></BLOCKQUOTE>

Sure it would be. As I was reminded here earlier on this forum, just lock in the E-drive and go.


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Regards,
-joe
63 2-dr Wag, 73 J-4000, 82 CJ-8

[MonsterMash]

<BLOCKQUOTE>quote:</font><HR>Originally posted by JeepFreak:
Mine would pop real bad in reverse. <HR></BLOCKQUOTE>

Senor Freak, was this popping sound as you were driving in reverse or when you put the rig into reverse. I sometimes get a serious thunk when I put my tranny in reverse and it worries me.

And Herr Grat, does your noise continue if you coast and put your tranny into neutral?

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'84GW360--"Spinner"
Bigger tires and better stereo but pretty much stock
Most everything works some of the time!
1st Annual Jefferson FSJ Mud Run:

http://home.earthlink.net/~worthservices/index.html

[Bnjnz]

spinner

i had a bad thunking sounf when i shifted into reverse. it was a bad ujoint in the driveshaft that was not moving properly when i shifted. i changed them out and there is no problem now.

benjamin
1991 GW

[JeepFreak]

Mine wasn't a driveshaft thunk. Mine made a popping noise when moving in reverse. It was obvious that it was the case chain. I have replaced my u-joints and I still get a thud when I put it in reverse. I think this is in my rearend. Probably a wore out ring and pinion gear in my case.

Joe, thats a very good point about the e-lock. Never even thought of that. See I knew there was a reason I joined this forum. http://www.ifsja.org/ubb/smile.gif
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JeepFreak

[This message has been edited by JeepFreak (edited December 02, 2000).]

[64Trvlr]

I addition to u-joints and chains making thunks and pops, you might want to check the engine, transmission, and transfer case mounts along with the crossmember bolts. My 2 cents worth.

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64 Traveler, 305/sm 465/
np 205/ d 44 ft and rear
w/4:88's,33.950.15

[GRAT]

I appreciate all the info. but I am still not sure. I do get a loud thunk when I shift into gear, but this noise is different.

I will check the chain.


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79 Chero WT/ TH400 /QT /360 /3" Dynomax / K&N

78 Chero WT 360 TH400

[scotty]

hate to break it to you gentlemen,but if the chain actually breaks,theres is no locking E drive and continuing on your way. the chain is also driving the rear on the BW 1339-no chain,no go. its also not any easier on the QT to disconnect the front,like it may be on the 229. with the 229,in 2wd,the chain will not spin,if the driveshaft is gone,or selectable hubs have been installed. with the QT,tho,the chain is still driving the whole vehicle,wether its splitting the torque between 1 or 2 axles.this happens at the other end of the chain,so the stress that the chain "sees" is the same,wether the front driveshaft is there or not.

if you suspect a bad chain on anything,especially a QT,id highly reccommend taking care of it ASAP. the longer you let it slip and POP,the more likely it is when you pull it out youll need new gears,too. more often than not,when the chain breaks,the results are catastrophic(went to the big word store this mornin) and the results are anywhere from a simple crack to a large gaping hole to a little pile of aluminum transfer case rubble under your jeep when it comes to a stop. ive seen it more than once. you may break a chain in a cast iron 203 and still be able to rebuild it,but more often than not,the chain will completely destroy an aluminum case beyond rebuilding. check it and fix it before its too late. mr. freak was very lucky that he was able to drive home after chain breakage.this is the first report of that ive ever heard-usually a towing vehicle of some sorts is needed http://www.ifsja.org/ubb/smile.gif


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scott
85 grand wagoneer
258 with motorcraft 2bbl/904/twin stick dana 300/dana 44/welded amc 20
38x15.5 gumbo mudders
snorkel/dual batteries/onboard air/"custom" convertable
3 inch body lift/mostly stock suspension/"modified" fender openings
custom front/rear bumpers and brushgaurd

T18/dana-spicer 18 with drum E brake and PTO swap very soon
searching for offset QT rear and PTO winch

[BIGYELLOW78J10]

Hey,

Is the vibration present under load? If it's only there when you are coasting, you may have lost the centering bearing in the CV joint on the front driveshaft. If you drive with the window down (and heater all the way up) and listen when you are moving but not on the gas and you hear a whirring clicking clacking noise, you may need a major front driveshaft rebuild. If you are lucky the CV is still rebuildable ($50). Unlucky (like me, around $200). Good Luck!

Daniel

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78 J-10 "Rumblin' Wreck"
2v 360 V-8
Stock down to the rust
Highway speed in about an Hour

[GRAT]

The vibration is present under load at freeway speeds, but the weird part is that not always is it present. At times I hit the gas and she runs fine, sometime I hear a knocking sound when the engine is idling at a stop light after freeway driving.

It sounds as if something is loose and knocking against somthing. I am going to check all the mounts this weekend. This one is really perplexing.


Thanks

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79 Chero WT/ TH400 /QT /360 /3" Dynomax / K&N

78 Chero WT 360 TH400