Problem with gears after ratio swap...

fastsc92

Registered User
I finished my gears in my 5 speed. 2.73- 3.27. Very nice gain. But i'm getting some noise. I had all the proper tools and did everything by the book. The pinion depth was right on....the backlash was .012 (specs are .008-.015) and the runout was only .001. Everything listed was perfect. The conntact pattern was also fine, right where it should be. I'll try to describe the noise.
The noise only happens at low speeds...while slowing down below 20mph. There is no noise at all while accelerating...or decelerating. There are no vibrations, and no howling. There is however...clicking. A deep clicking noise....not loud...but noticable. This only happens at speeds below 20mph while slowing down. There is no clunking at take off or reverse. I've gone through everything and i cant understand it. I've seen gears that were done wrong, and they either howl while accelerating...or decelerating. Mine does neither, just clicking. I cant figure it out. Maybe they need to break in some more before i jump to conclusions. Someone please shed some light on the issue. Thanks
 
I've always gotten that click (or ting) on both of my cars on take off and I don't worry about it. But the other noise could be a wheel bearing going bad. Did you put on new axle nuts torqued to 250ft.lb. and some friction modifier in the diff? A friend replaced his diff while trying to get rid of that noise and it turned out to be a bearing. Good luck
 
its not the wheel bearings, and it only happens coming to a stop....not taking off. I did get new axle nuts and it did tighten them to 240 ft. lbs. I think i might have found the problem ( at least its worth a try..) I changed all the bushing in the rear including the diff bushings with poly ones. This could have changed the pinion angle to the driveshaft. The stock ones had 102,000 miles on them. The change in angle could make the noise. They are the factory u-joints with the same miles on them and thye might not be used to the change in rotation angle. What do you guys think??
 
I hope you're right, but my experience has been that driveline vibrations usually accompany a pool pinion angle. good luck
 
i understand, but there are no vibrations at any time Just the clicking. Usally when gears are junk, they howl and vibrate. These do none of this. Thats why i posted it. I think its weird that it only has that deep clicking at speeds below 20mph while slowing down only.
 
You should be able to tell the difference between the speed of a click coming from the wheels or from the driveshaft. Remember the driveshaft is turning 3.27 times faster than the wheels.

If you are not sure then tape a piece of tin to a tire and then drive and see if it is in time with it or 3+ times as fast. Should help you narrow it down.
 
To add more conjecture, it could be a bad CV joint in one of the half shafts for the rear.

I had a very similar sound in a old Dodge Omni that had a CV joint fail.

I think a bearing would be more of a grinding , rather than clicking sound.

Could also be an issue with u-joints, but I wouldn't think a slight pinion angle change would cause noise, though it could cause vibration.
 
i'll try the u-joint first....then i'll looking into some axles. should i change both u-joints...or jsut the rear one. Everything was fine before i took it apart, now i get clicking. Maybe taking the shalfs out damaged them.
 
CV joints can not be easily damaged. And yes, Diffs can click. But if everything was done right, and it's full of fluid, it shouldn't be clicking.

As far as the CV joints in the half shafts. What can happen is that when you remove it, it can move in a larger range of motion than what it typically would move. Especially the inward CV joints. This untypical movement can sometimes cause problems with very worn joints. My Taurus with only 43,000 miles failed an inner CV joint after a transmission input seal was replaced under warranty.

It might help to just jack the rear wheels up and spin them listening for something.
 
well the pinion angle was changed because of the solid bushings and also the car was lowered 1.5" at the same time, so each of those parts ( axles and u-joint) are in a different range of motion.
 
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