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Any mechanic with the slightest bit of pride in their work will be able to do your install. The thing is that person is going to cost a bit more than you may want to pay. Fabricating the pins, depending on inventory and equipment, could take a couple extra days and add a couple of hours labor. Not having the same equipment available to me that I had access to during my 40 year career has been stressful. When I needed my alignment I took it to a performance shop, new to the area, but lined with modified late model street cars. I arranged the appointment so I could wait, brought a book and waited. When I saw the long wooden access ramps attached to the alignment rack I knew I had probably made a good choice. Their alignment guy came in and stated that he could just get the caster to the minimum spec but the camber was good. Was that acceptable and I said by all means. Modifications require compromise. I’d he had stated that we were short on the caster I would have replied that I will drive it and see if the steering is stable at speed and make the call. I know they would have been fine with that. I got lucky finding these guys with my first educated guess. You may not be as lucky but my 40 years allows me to read a shop much better than the average consumer.
I have a RCSB with one piece driveshaft and I used a BellTech 4" flip kit. Their supplied shims did nothing for the driveshaft hop so I ordered up enough to get rid of it and I ended up at a -1 pinion angle. Remember that the pinion rises under acceleration so I am probably going +1 or more under hard acceleration or with a load in the bed. It is all a compromise. The problem with the extra shims to get to -1 was the locating pins on the springs were too short. I hopped on McMaster-Car ordered up the correct hardness and thread in a cap screw to replace the factory pins. Some slight machining on the cap screw head to decrease diameter and then shortening one of the heads so it would not contact the axle tube and I was all set. If you have to add more than one shim to a BellTech flip kit you need to build new locating pins. Most of the flip kits will be like the BellTech.
Newport, what did you order from McMaster-Carr? I have same truck with same lowering kit and having the same issue. Thanks!
Clay,
I just went back through my purchases and found the invoice. I do not remember which bolt I ended up using but better to have what you need than tear your truck apart and have to wait a couple of days because the bolt you got was to short. You can always cut a longer bolt. After looking at the invoice I remember exactly what I did. Bolt head to the streetside of the spring with a hardened washer. The socket nut was then machined to fit the axle hole diameter and height. You do not want the axle tube hitting the socket nut. Adjust the height of the socket nut after a test fit not before. It is really easy to end up too short. The shims will need to be ovaled out a bit and you may have to do the same thing to the axle locator pin hole also. Its been almost two years and my memory is not what it used to be but the process would come right back if I needed to do it again..
So after many adjustments and basically just moving a slight vibration to a different mph but never completely getting rid of it I dove 100% in last week to fix it once and for all. I had probably 5 hours total adjusting, measuring, running numbers through the Spicer calculator etc but in the end it was worth it.
We have 3 working angles calculated from 4 points. The trans, 1st shaft, 2nd shaft and pinion...all working angles should be 3° or less and the angle of the 2nd shaft needs to match the angle of the pinion...or so say the experts. No matter what I did I couldn’t get those to work out. If the 2nd shaft and pinion matched the working angle was too great and vice versa...I attribute this to the 5” drop changing things so much. I settled on getting the working angles < 3° As it seemed like the lesser of 2 evils and the difference between the 2nd shaft and pinion was still less than 1°
Getting there was the hard part. I had to shim the trans tail shaft up 1/2”, shim the carrier bearing down 1/4” (I have the McGaughys carrier bearing bracket installed so a stock one would be different) then dial in the pinion angle with the DJM flip kit bracket I put in a while back...all while keeping in mind that the 2nd shaft and pinion angles need to form a downward V. You can achieve that even with the pinion angled up...so it gets a bit confusing.
I’m attaching a pic of the Spicer calculator and where I wound up. I’ve driven it for several days including acceleration tests at 25% throttle, 50%, 75% and WOT through 3rd gear. No vibrations I can detect at any speeds so I think it’s finally good.
Keep in mind no working angle can be less than .5* or the u-joint needles won’t spin and lubricate themselves...the joints will wear out just as fast as too much angle.
Hello, I have a 2021 f150 2.7 ihc suspension lowered 4f 6b. I had many problems with the vibration in my driveshaft from 15 to 30 and from 65 and up. I looked for many local places that could help me, I spent a lot of money but none helped me, but looking for information here in the forum I found a lot of information that helped me a lot. Thank you very much (UNBROKEN). I shim the trans up 1/2 I use IHC carrier bearing bracket also in the flip kit puce 4 degrees shim it all depends on the angle they have on the back
I just finished up my 3/5 IHC kit on a 2019 2WD and got the below angles. I’m experiencing some slight vibrations above 15 mph and was wondering the best way to approach a fix. I have the IHC carrier bearing relocation mount I can add as well or I can get some axel shims.
Should I try and get all 3 operating angles within 1 degree of each other or is having the 2 u joints (A and C) within 1 degree okay? Should the transmission and axel angles be within 1 degree or is it strictly the operating angle? Thanks for any advice!
How and where are you measuring to get the angles?
I took them with a digital angle finder with the truck on the ground. I measured the transmission off a back flange, both driveshafts and then a few areas on the rear end.
it was hard to get all the angles with the truck on the ground, so I will re check them this weekend as well. I would expect the trans and first shaft to not change and just adjust the second and rear. I just am having trouble visualizing what should be adjusted.
Hello, I have a 2021 f150 2.7 ihc suspension lowered 4f 6b. I had many problems with the vibration in my driveshaft from 15 to 30 and from 65 and up. I looked for many local places that could help me, I spent a lot of money but none helped me, but looking for information here in the forum I found a lot of information that helped me a lot. Thank you very much (UNBROKEN). I shim the trans up 1/2 I use IHC carrier bearing bracket also in the flip kit puce 4 degrees shim it all depends on the angle they have on the back
Did you notice any issues when you notched your crossmember? I have the IHC carrier bearing bracket and they suggested cutting it like you have shown.
Let me tell you.... I never would of guessed there's so much extra work with eliminating drive line vibration when lowering a 2wd SCREW. I currently have 2 inch drop shackles with 2.5* shims with no issues. I did my research before going to a 4 inch flip kit and ot seems that shims aren't going to cut it to eliminate vibration on the two piece shafts. I was considering lowering the carrier bearing instead of raising it to create an V shape that could be in the right operating degree limit with the correct pinion angle. It seems when you mount the carrier bearing to the cross member, there's still issues with vibration with shims from 2 degrees all the way to 6 because the shafts aren't in the correct angles still. Crazy.
Vibrations in a driveshaft are a relatively simple problem to diagnose. Fixing the vibration may not always be simple, especially with altered truck suspensions (read lifted or lowered). Trucks are usually setup with the transmission pointing down and the pinion angle pointing up at near equal amounts. U joints should have a minimum of .5 degrees of angle to promote proper needle bearing rotation and good wear. They should not have more than 3.5 degrees of working angle to prevent binding. Each joint creates a vibration and it takes an equal but opposite angle to cancel it out. There also shouldn’t be more than .5 degree difference in the angles.
On a one piece shaft the angles of the front joint and rear joint should be equal but opposite. For example if the center line of the transmission is 5 degrees, the shaft angle is 7 degrees (giving a downward angle of 2 degrees) and the differential centerline is 5 degrees (upward angle of 2 degrees) these being equal but opposite there would be no notable vibration. (You could have a 2.5 degree angle at the differential and this would help prevent binding under hard acceleration or takeoff with a heavy load as the rear axle pinion nose tilts up)
On a two piece shaft, if the trans centerline is 5 degrees, you would want the front shaft angle to be (ideally) 4.5 or 5.5 degrees giving you a .5 degree working angle angle. Then the rear shaft to be sloped down no more than 8 or 9 degrees respectively and the differential centerline matching the front shaft angle at 4.5 or 5.5. This would achieve the maximum joint working angles and equal but opposite angles canceling out the vibrations created by one another. These are maximum working angles
On the angles posted in the angle calculator above, if I am reading it correctly the trans centerline is down 5 degrees, the front shaft is down at a lesser angle of 3.75 degrees giving a working angle at the trans yoke of 1.25 degrees (5 - 3.75 = 1.25 up angle because the shaft angle is less than the trans
the rear shaft angle is 1.75 degrees giving a working angle of 2 degrees up angle (3.75 - 1.25 = 2) because both these angles are in the same direction the total working angle is 3.25 degrees.
the rear shaft at 1.75 degrees and the differential centerline being 2.25 (the selection says it is pointing down giving a working angle of .5 in the opposite angle. This ends up giving a total working angle of 2.75 degrees 1.25 + 2 - .5 = 2.75. It is kind of a mess but if it doesn’t vibrate then consider me surprised.
Live axle rear wheel drive cars are setup with the transmission pointing up, the pinion angle down so opposite angles can be achieved.
12-15-2018, 12:44 PM
