Drive Line Direction
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From: Graham, Wa.
Drive Line Direction
I have been chasing a vibration at about 45mph so I have taken the drive lines out and had ALL the u-joints replaced and had all 3 balanced, had new tires put on and balanced, and still can't shake the shudder. I did notice that way that the PO had the drivelines in before had the slip yolks facing the differentials on the long shafts, but facing the tranny on the intermediate shaft. Should the yolk be facing that way on the short shaft? I am just wondering if this one is facing the wrong direction, and if it would make a difference. Thanks.
Believe Nothing
Joined: Jun 2004
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From: W. Central FL.
I am going to assume you mean you had the fully assembled driveshafts balanced and checked for runout. You fail to say what the exact configuration of your truck is. Year, model, 2 or 4 wd, engine, transmission, transferr case, mods etc. I believe we're talking 4wd as you mention differentials. How about the axle joints? Be aware that certain truck configurations in the dent series had a weight attached to the rear of the cab to prevent harmonic vibrations.
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From: Graham, Wa.
I did have all 3 drive shafts balanced as a unit by a very good local shop. This is a 4x4 with a 390 and a C6/np203. The question now is what start looking into next? I suspect that the transfer case may be culprit as I noticed that someone did the "part time" conversion on it and it was locked in 2wd so no oil was getting up top. When I did change the oil, it was nasty dark, but did not find any metal filings. Any suggestions on when to focus next would be appreciated. I ultimately plan to go through everything, just can't do it all at once. Thanks.
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From: British Columbia, Canada
The slip yokes on the driveshaft should be facing the rear of the truck, regardless. My thought is you should try getting her up to speed and start putting everything in Neutral. If the shudder goes away, then you can eliminate the TC or tranny.
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From: Ideeho
DRIVE LINE PHASING
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From: British Columbia, Canada
Not to put words in your mouth seventysevenF150, but he means are the driveshafts "in phase"? If you had them balanced, Im sure the driveline shop had them phased correctly. However, if you pulled the slip yoke apart on them at some point that could be your problem. Here is a link to some good info regarding drivelines..........hope it helps.
DRIVE LINE PHASING
DRIVE LINE PHASING
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From: Graham, Wa.
The driveline shop did mark the yolk and the splines for me and I did not separate them prior to installation. Funny that you suggest that all the yolks should be facing the rear of the truck as 2 of them are facing forward. When I asked the driveline shop if this made a difference, they did not see to think it should matter.
We will give that a shot first as it is a "no cost" project. Thanks for the info.
We will give that a shot first as it is a "no cost" project. Thanks for the info.
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Cargo Master
Joined: Oct 2010
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From: Ideeho
I think Id check pinion and transfer case yoke angles as well. When you have the shafts out would be the perfect opportunity. You can do that with one of these type guages. This one is from Harbor Freight. Just using the pic for a reference. I think I have some of this issue going on with my 78 F150 due to some broken leaf springs in the rear. I havent checked it out yet, since Ive got the springs, just havent had time to get em put in yet. The vibration started showing up about the time I noticed the leaves were broken. Heres the guage Im refering to.
Dial Gauge Angle Finder
Dial Gauge Angle Finder
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From: British Columbia, Canada
The reason for having the slip yokes facing the rear in my opinion is the small hole in the end of the shaft on the slipyoke end that houses the grease for the slip yoke will be blasted with road grime, water, sand and what have you from driving, if you had them facing forward. Facing the back would eliminate this from happening. you don't want crap getting in there. One other thing I thought of was, before you put the driveshaft in, did you check & clean the lip that holds the cup of the u-joint on the flange?? Could be crap crushed between, throwing the the joint out of balance.
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From: Graham, Wa.
Well I went back under the truck and started wiggling everything around to see if I could find something, and low and behold the shaft out of the C6 had some play in it. Not a lot, but I don't imagine any is good. It is currently sitting on the floor of my shop waiting to be rebuilt. Hopefully this takes care of the issue.
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