|10-30-2012 07:12 AM|
|1Gary||For yrs I was convinced that the trans output had to be in a straight line with the rear end pinon.Some off road guys convinced me that isn't necessary true.That as long as the trans output and the pinion was in the same plane it didn't matter if there was "some" offset of the rear-end.|
|10-29-2012 02:55 PM|
|10-29-2012 07:24 AM|
drive line info
Spicer technical information is a good reference to read and has a chart to calculate when engine centerline and rear pinion are off set both up and down and left to right, check them out " spicer drive shaft installation"
|10-29-2012 03:28 AM|
|10-28-2012 09:40 PM|
|10-28-2012 07:13 PM|
I just read on this website that you would want the front shaft to sit level with the transmission then then install the rear shaft as a one piece shaft. http://www.iedls.com/asp/admin/getFi...&TID=28&FN=PDF
|10-28-2012 04:08 PM|
Thanks again for all the advice, if anyone has any advice on how to set-up the driveshafts than that would be a big help, I find very little on-line that pertains to having two shafts.
At this point I am setting the engine in place with a level carb which has given me an approx 3-4 degree downward pitch at my tailshaft.
From the little bit I have been able to find and unless I am mistaken you never want the driveshaft to sit level with the carrier bearing ( which is mounted in between the two shafts and hangs off the frame ) If it is level than the bearings within the u-joint never actually get to work and the joint will somehow wear out quicker.
So ( again unless I am mistaken ) you want the two pitches to cancel out one another which sounds to me as if you would want to make sure that the carrier bearing is a bit higher than the tailshaft end of the U-joint so that there is a 3-4 degree pitch upward in other words.
I am still confused though ( maybe on it all ) on how this is all going to affect the rear end driveshaft or secondary shaft pitch.
This is a multi-ton truck and the rear end in it is enormous and I cant imagine trying to fool with adjusting that pitch with shims ect.
I have call Dana, ( or I guess it may have been Spicer ) they have a tech line and they are pretty knowledgeable but they tell me they cant tell me where to even start. The best they can do is tell me how to fix it once it is set-up.
In other words they are telling me to get everything in place, get my driveshafts cut balanced and hung and then measure the different degrees they require and they will tell me where I need to adjust to get the most balance out of the deal.
Dosent make alot of sense to me but at this point it is the most help I have had offered from anyone.
Trucks gonna go down the road at slow speeds, maybe it will see the highway, maybe 60 or 65 MPH tops though I would imagine but I would like it to run as vibration free as possible.
I know this sort of stuff is prob. out of alot of you guys interest but I may as well throw it out there and see what anyone has to suggest.
|10-28-2012 02:34 PM|
Wouldn't you want it square with the frame and if the your rear end is off that far, fix it?
|10-28-2012 02:31 PM|
|10-28-2012 02:29 PM|
|10-28-2012 02:24 PM|
Tech, what would be the difference if it was measured from the center of the differential or the frame?
|10-28-2012 02:15 PM|
Measure the center line of the car off the differential, not the frame. Use a plumb bob dropped off the center of the axle on each side right up next to the backing plate at EXACTLY the same place on each side of the differential.
Tie a piece of line (a piece of chalk line will work fine) around the diff tube on each side at exactly the same distance from the brake backing plate on each side, as close toward the backing plate as you can get. This line will be larger in diameter than the diff tube. For instance, if the diff tube is 3" in diameter, make your line maybe 5 or 6 inches in diameter. The idea here is to have a piece of line tied around the diff tube that is larger than the diff tube and will hang down around the tube. Now, when you run a piece of line through that hoop, with a plumb bob on the line, the plumb bob will hang down toward the floor at exactly the center of the diff tube. The circle of line around the diff tube will look like the lobe of a cam once the weight of the plumb bob is on it. Make a mark with a Sharpie where the plumb bob touches the floor. You will have two marks on the floor, each indicating the center of the diff tube and exactly the same distance from the backing plates on each side.
Have a buddy hold one end of another line down on the Sharpie mark. It will be helpful if you tie a knot in the line and keep the knot on the Sharpie mark. You will be on the other end of the line, with the Sharpie tied on the line. Holding the Sharpie exactly straight up and down and keeping the line taught, scribe an arc on the floor, approximately at the front wheel, fore to aft. Now, have your buddy move to the other Sharpie mark at the diff and hold the knot on that mark while you swing another arc. Where these two arcs cross is the exact center of the car, as referrenced off the differential. Now have your buddy shorten the line by tying another knot in the line, maybe two feet shorter than it was the first time. Same exercise over again. Your buddy holds the knot on one of the Sharpie marks at the diff while you swing an arc with the other end of the line. Now, your buddy moves to the other side, holds the knot on the other Sharpie mark and you swing another arc at the front. The centers of these arcs will be the centerline of the car and you can snap a line, front to rear, off the centerpoints of the two sets of arcs. Then use a 90 degree square to determine another line, either to the driver's or passenger's side of the car. Lay the square on the centerline at one of the arc centerlines and measure how far you want to move the engine/trans. Make a mark. Now move to the other crosspoint at the center of the car and measure the same distance. Now snap a chalk line fore and aft on those two marks and you have the center of where you want the engine/trans. This method will place the engine/trans exactly perpendicular to the differential.
You can swing as many arcs as you want to. Just keep shortening the line each time and tying a new knot in it for your buddy to hold on the rear Sharpie marks.
|10-28-2012 01:50 PM|
|Oilyrascal||Thanks for the help, I am a bodyman so I pretty familiar with the tram. I guess I am or was overthinking it. I just wanted to be sure when I do this again that I have done it with a little more know-how.|
|10-28-2012 09:37 AM|
If you aren't clear on the cross measuring, measure from 2 to 3 and 1 to 4 in the first one, if they are the same, those points are "square". If you are confused on where exactly the point is on the frame you can measure from 2 to 4 or from 1 to 3 or 5 to be sure you are using the same ones.
But honestly, you see very quickly if you are wrong because the numbers are off a mile. These cross measurements on a frame like your truck should be within about a quarter inch difference from one to another.
You measure one, then cross to the other, when you find it's good, simply go to another point near by to confirm you are using a good point, once you have a few you KNOW you are good to go.
|10-28-2012 09:31 AM|
The frame is symmetrical if that is what you are saying, it is the same from side to side.
If you have any doubt, cross measure it like this.
If you are using the same points side to side and you cross measure and the distance comes up the same, you are good to go.
Then using those control points that you have confirmed to be the same on both sides by your cross measuring.
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