Detroit lockers can feel like a jerk. It was meant as a joke, but is a possibility. Check your u-joints again. With the tranny out of gear, truck on the ground (and off) try to spin the shaft either way. You will feel that it has some freedom, it means your u-joints need to be replaced. This is really the only thing that causes a jerk, and it's not that expensive.
-Mike

 

I checked them again and couldnt budge the driveshaft one bit. Does it matter that it had pressure on it from it bein in gear?? And feeling up and down the driveshaft there is one weight on each end and there is also a lil bir near each weight, so its possible im missing weights

 

How many drive shafts do you have/do you have a 2 part shaft. Did you try twisting both parts? That testing procedure might not be right, I was hoping someone would chime in. Did you pull the diff cover yet? And the jerk may be completely unrelated to the vibration problem. I'll have to do some thinkin.
-Mike

 

I have one driveshaft in the front and one in the back its 4x4 and I dont know if its a two part or not.

And I may be pulling the diff cover this friday, (I gotta get some time to do it lol) when I do I will put a magnet to the old oil and check for any shavings

I was able to get onto a highway yesterday and it was constant at high speed it wasnt real bad, its possible the jerk may just be an on and off real hard vibration? just a thought you know more than I do... On my way to work today ill turn the radio off and try to pay real close attention to it.

 

Yes, it matters that the truck's in gear when you check. You have to remove all the tension in the driveline to check u-joints for slop.

 

For sure. All the slack is taken up and usually under enough pressure
to prevent you from feeling any slack or play in the parts.

Seems to me you got to?

2wd with Mazda manual or automatic transmissions have the slip joint
built into the tail piece. You are the one that ultimately has to figure all
this out, all we can do is help speed up -that- process, ok? ;)

Wow, just had a funny thought...

I wonder how many vehicles have broke down and left people stranded
because they didn't hear the "new noises" warning them of problems?
Instead just drove it 'til it quit on 'em, because they "had tunes"? LOL :)

The '75 F150 I special ordered when I was 21 has never broke down
and left me stranded -anywhere-, -ever-!



"new noises (or vibrations;) are bad, look into them right away!" -Alvin

Alvin in AZ

 

Well Poke your head under and look. My '93 has as 2 part shaft with a carrier bearing. It adds a few extra u-joints and a bearing to fail. And recheck those joints.
-Mike

 

Good Point!! Never thought it that way before! lol

And I will recheck u-joints and probably pull the diff covers friday (Got a couple essays due and work so goin to be busy next couple days) and post results. I will also look and see what kind a driveshaft I got to.

And sorry if this is a no-brainer ? but in order for me to have a 2 part drive shaft does it have the carrier bearing, if so the I have a one part.

She hasnt been maintained very well with previous owners but that has changed with this one! even though my dad owns it and he just lets me have the privlidge of driving it lol

 

Just out of curiousity would a slipping clutch provide any of the vibrations? I noticed today that my clutch is begining to slip. Speedo dont work so still hard to tell. But out of curiosity would it provide a vibration/jerk?

 

So, the same question from post 1. What did it look like when you popped the inspection port? Was there clutch left? Any oil residue? Were you getting a full range of travel from the slave? You have to be our eyes and ears. Did you get a second opinion on the clutch? I don't think it would vibrate or jerk with this regularity.
-Mike

 

Inspection Port- I looked in and saw the disc (fist time I have seen a clutch disc that wasnt in a picture.) So from what
I uderstand its basically a giant brake pad that wears down over time. I looked and its not down to the rivits yet looks like it has a way to go yet. No way to check clutch motion yet Ive been by myslef so far but will do soon. and havent gotton a second opinion yet.

U-joints- Did as ya'll said and back one has pretty good slop and will replace as soon as I get a chance.

One question about the clutch where the front od the bell housin (engine side) There is fluid leaking out the bottom.. Could my slave cylinder be leaking and causein to slip? I just happen to notice it and didnt know if it would be relevant to this. Tryin to give ya'll all the info I can

Thanks! Josh

 

Yes, if it is in the housing, not where the housing meets the engine. Could be your rear main (hope not).
-Mike

 

Depends on what the fluid is. If it's brake fluid then your slave is leaking.

 

Ok so will try to get some pics soon but dont if I can upload. But I got new information!! I have been paying attention to it lately listining and feelin for anything new and a kinda high pitch squeking noise is there now. U-joints?

But I did get some second opinions on the clutch and u-joints. He said he didnt think the clutch was slipping but to me it seems like it doesnt accerlerate as much when getting over 1800rpm and also seems like it revs quicker. On the u-joints He said they were fine but for $20 a peice I might anyway. What he did notice was some slack the pinion of the rearend (where the drive-shaft bolts up) You can tur it about a half inch to and inch in either direction before it stops. I dont know if it is relevent but tomorrow I pullin the driveshaft off and am goin to check it out.

Thanks Josh!

 

Got some new u-joints and almost completely went away the rear one was so locked up that there wasnt any slack in it. The jerk is still there so thinking it may be related to the pinion in the rearend it has a quite a bit of slack!

Thanks for all the help! Josh