Lowered car pinion angle

[shelby69]

I have a 69 Coupe. I put in 1" lowering blocks on the leafs and 1" lowered coil springs in the front. Since then I seem to have a little driveline noise/rumble at about 50-70mph. Do I need to change the pinion angle? Does my stock driveshaft need to be balanced? Any ideas?
Thanks

 

[ForceFed70]

Check that the driveshaft isn't coming in contact with the exhaust since it's been lowered.

I'd also start by checking the driveshaft U-joints.

 

[HistoricMustang]

I have a 69 Coupe. I put in 1" lowering blocks on the leafs and 1" lowered coil springs in the front. Since then I seem to have a little driveline noise/rumble at about 50-70mph. Do I need to change the pinion angle? Does my stock driveshaft need to be balanced? Any ideas?
Thanks

Just had a thread on pinion angles. You might do a search. ( Hint: the new angle will be OK)

If the driveshaft was OK before it will be OK now provided it was marked before removing to put back in same position.

HistoricMustang
www.historicmustang.com

 

[zookeeper]

I've dropped many cars, and I can relate to your problem. Sometimes you need to adjust the pinion angle on severely lowered cars and trucks, but usually not on mild drops. But, evidently something's changed if you're getting noise or vibration after you lowered it, right? Here's how to see if the pinion angle is OK or not. The pinion angle needs to be the same as the transmission output shaft, regardless of what it is relative to the ground. To check it, remove the driveshaft and use an angle finder to measure the angle of the trans output shaft. Angle finders are cheap ( under $20) and sold at lots of tool and hardware stores, I got mine at Sears ten years ago. If you measure the trans output and get (for example) a reading of 5 degrees as measured off of a MACHINED surface, you need to have the pinion at the same angle, again as measured off of a machined surface. Never measure off of a casting, your results will not be accurate. If the readings are off, I would have the lowering blocks milled off at an angle to correct the problem. It's a fairly straightforward job that only requires a little math and a little cutting, it shouldn't take more than a half hour at a machine shop. If you don't have lowering blocks, you can also buy or make angled shims to correct pinion angle on leaf-spring cars. Since most cars don't have leaf springs anymore, you'll probably have better luck with shops that lower (or lift) pickups.