So, I am looking for some advice from someone who knows a bit more about bodywork than myself. I have a stretched F350 as shown in the pic. Not newly stretched and the previous owner did tell me that this issue existed the entire time he owned it as well. However, I believe when they stretched the cab, they moved the carrier bearing back decreasing the angle of the dangle so to speak. The drive-line about 6 inches from the slip yoke on the business end rubs a body cross-brace when I run over dips in the road or run over a bridge. My question is this. Would it significantly effect the integrity/safety of the body if I were to take a hammer and flatten the brace out just a little bit to create a little more clearance ? My initial thought is that it probably would be fine, but then I think well why would they brace the body if it didn't need some backbone in this area of the body. I just don't want to hammer away at the cross brace making more room for the drive-line and then find stress cracks in the body at a later date. Also the rubbing is dependent upon how much weight I happen to have in the cab. Driving around solo, it doesn't strike the body, but full of passengers, it strikes it pretty good. I had initially thought that the yoke itself was striking the body because of the noise being an air hammer type noise instead of a bump. But it was dependent on how big the dip in the road was. little dips was just a bump against the body, big dips I could hear the ujoints turning over. I want to fix this sooner rather than later, because I am concerned the big bumps may be putting a significant amount of tortion on the tail shaft and don't want to break the tailshaft of my transmission and have bigger problems. I will try and take some pictures after daylight to help you guys get a better visual of my scenario. Anyhow I look forward to chatting with you in regards to this issue.
On trucks that use a center bearing, they have a crossmember made just for the carrier, it steps down about 5 inches and goes from framerail to framerail, and there is plenty of clearance for the drive shaft, it should be noway near hitting the floor board, I would like to see what they did when they stretched that frame. The front shaft is usually straight from trans to center bearing, than from the bearing to the diff, it drops. You got me very curious as to what they did. Get some photo's to us and lets see what's going on.
So when they stretched the truck (I would say a total of 24in or so) they moved the carrrier bearing back behind the add on. The original driveshaft was probably still 2-piece, but it seems the front driveshaft would have been maybe only 18in long. The carrier bearing cross brace is still mounted in the original place on the frame. They just made a new one or used the carrier bearing crossbrace from the donor truck. I have taken numerous pictures underneath the truck and hope that they turned out ok. The front driveshaft is rubbing the body cross-brace about 6in behind the slip yoke on the driveshaft. My concern is that I would have to drop the carrier bearing significantly in order to change the spacing between the body and the shaft. Im not necessarily hell bent on redneck engineering this, but would like the simplest solution that is not going to make this a safety issue. If a little massage with a BFH on this cross brace is not the best idea, Ill find another solution. However if it is easily remedied without significantly affecting the integrity of the body then this seems to be one of the more simple possibilities. Oh and for the record, the driveline does not rub when I am solo. However when I loaded the fam in the truck to use it as I meant to use it, I had the problem with the driveline striking the body. Initially, from the way it sounded, I thought that the yoke itself was striking the body but as it turns out it is only the shaft. I am going to try and post the pictures on this post if I can figure it out, however I may just have to make an album in my photos in re to this problem.
Also it appears they may have replaced the OE front section with a larger diameter shaft. I would say the shaft is about 4in diameter. The rear shaft appears to be about 3in diameter. I have also noted over the past few days that the body could be sagging some. The pin stripes don't line up perfect from the body to the box. they are at least 1/4-1/2 in difference. So it seems that many ingredients have added up to the perfect storm. My dad is convinced that the transmission mount also may be shot. I am not completely discounting that possibility but, it only has problems when I have the family in the cab with me. Driving it solo it never strikes the body. I would think if the trans mount was the culprit, it would allow the driveline to heel and strike the underbody without regard of how much weight was in the cab. Anyhow take a look and let me know your take on the situation. I always hold high regard a second and third opinion. The more sets of eyes the better. Thanks for your time and have a great weekend.