I wanted to get some other ideas here. I have lowered my car just where I like it. I'm using a 1" lowering block in the rear and cut coils in the front with the shelby 2" drop from Pro-Motorsports. I'm using a 92 5.0l EFI HO with a T-5 and the stock 8" rear axle with a 3.50 gearset. Here's my issue: I have tried various combinations of lowering/raising the engine and transmission mounts and shimming the rear axle to attempt to get pinion angle where I want it but when I get it any where close to offsetting angles, either the front or rear of the driveshaft will make contact with the tunnel sheet metal. Has anyone else experienced this situation? I've had the driveshaft balanced and check for runout 3 times (it was shortened for the T-5 conversion) and I have a 1.5-2 deg angle split which explains the vibration (high frequency) beginning around 55mph and horrible on decel. I'm about ready to cut the tunnel out and raise it about 1.5" to clear the driveshaft at both ends so I have room for adjustment but I wanted to get some advise/input before I cut the rust free floor of my car. I do a lot of hwy driving and eventually I'm going to spit the driveshaft out if this isn't corrected soon. Any ideas/alternatives?
i have mine lowered about 2" all around, no issues. I have my pinion angle at 0. Qieter ride that way. But even when it was at 3 degrees, still nowhere near touching anything.
usually you want the pinion ange 2 degrees down from the angle of the motor/trans. im sure youve reseached this as your post shows that you have tried alot of things. how sure are you about the condition of the drive shaft it self. do you have the right u-joint cap size on the rear. thats a common problem. mavericks use a large cap 1310 size ujoint. most 1310 series ujoint use a small cap. is the shaft streight and has it been balanced? i would try to the the rear of the trans as hi as possible and the front of motor down if possible. then set the pinion angle to the 2 degrees below the angle at the trans.
Can you shoot a picture of where it is touching? I am having a hard time envisioning this, and apparently, so is everyone else... Sounds like something other than pinion angle is installed incorrectly, but cannot tell for sure without seeing it.
I'll post pictures later of the affected areas. I have had the driveshaft balanced and checked for runout and the u-joints fit and are what NAPA had listed as the correct parts. The T-5 setup required me to have it shortened, but my angles are as follows: trans angled down 2.5 deg, rear end angled up 0.5 deg, driveshaft angles up about 1 deg from trans to rear end at ride hieght. If I raise the trans any higher the driveshaft actually contacts the tunnel just behind where the floor hump for the shifter is and if I angle the pinion up the drivshaft hits where tunnel at the lowest point just in front of the pinion snubber. (this usually only occurs with someone in the back seat or weight in the trunk) Just trying to make sure I'm not missing something obvious. I had to cut out the forward portion of the trans tunnel for the shifter tube and top of the T-5 already but I want to make sure I only have to do the tunnel once.
OK, if the trans is angled down 2.5 degrees..............the pinion on the rear end should be "UP" 2.5 degrees................U joints are made to work "in phase", and an out of phase driveshaft can cause a vibration the same as different angles on the tranny side and pinion side. But having the front U joint at 2.5 degrees down and the rear at 1 degree up is not acceptable. Leave the tranny at 2.5 down and shim the rearend to 2.5 up..........if this doesn't get rid of the vibration you have other issues. The other issue is having the front U joint at 0 and the rear at 0; U joints are not made to operate in this conditon.
My issue is that if I shim the rear end up to 2.5 degrees, the driveshaft makes contact with the tunnel and the pinion snubber bracket which is why I am considering raising the tunnel. I was going to try to raise the trans up to an operating angle of around 1.5 degrees and tip the rear end up slightly to the matching opposing angle. If it's what I have to do, so be it. I figured I can't be the only one with this concern and was just looking for a different viewpoint. If I tilt the trans down, my headers are real close to the ground and the rear would have to be tilted up almost 4 degrees and that seemed a little radical.(4X4ish) and the driveshaft looked funny going up hill that far. :16suspect It's just a daily driven street car and I'm more concerned with practicality and reliability and I don't want to spit out a u-joint if I hop on the hwy and head to KY this summer Again, Thanks everyone for your input.
One last comment. If you can get the trans to 1.5 down angle and the rear is already at 1.5 up angle......................then go with it. It should work. It's not optimum, but should work fine. When setting up the drive train and a carb'd car, you usually set the carb mounting pad as close to 0 as possible, then that dictates where the tranny angle is and the rear end angle should be, on EFI cars it really doesn't make any difference as long the drive shaft angle is not at 0.
I've used 2 different crossmembers. I modified the original C4 crossmember and the drivetrain was down over 4 degrees. It looked cobbled together so I made a crossmember that I can add/remove shims to lower or raise the tailshaft of the trans. that has put me at 2.5 degrees down. any idea what the OEM angle is? olerodder mentioned carb angle but I don't remember what the original drivetrain angle was with stock mounts. If I raise the rear end, I'll have more clearance for adjustment, but I really like the way it looks with the rear where it is. It's not slammed but I'm running 16"s with a 245/50R16 and I really can't afford to go bigger. I'm 8" at the front and 8.25" at the rear on the rocker panel so the car isn't too low, I don't think anyway. If anyone can measure or knows the stock angle off the top of their head, that would be great. at least I would know where I started from. As far as ideal, I have found a lot of info on drive line angles but none actually say what is an ideal driveline angle, just that they need to be equal and opposed for smooth operation. I know some race angles are geared toward traction more than comfort but this is a daily driver. So what is the ideal angle if you're setting up a chassis from scratch? Thanks again for thoughts and input
Before I removed the top loader from my car, I measured the distance from the tunnel to the output shaft. It was exactly 4 inches. Now, I don't know if this can be directly used for the T5, I don't know the length differences. If its longer, then the tunnel might collapse down the farther rearward you go. Also, I used the original C4 cross-member with the top loader. You might want to get this measurement from someone running a T5, it could be a good starting point.
