Now that I have my Wavetrac unit installed in the car, the driveline makes a "bump" noise sometimes when putting it in gear and during some mild shift conditions. I've put the car back in the air and double-checked the differential mounting bolts torques and driveshaft bolts. Since the Wavetrac & Quaife diffs have more cross gears between the axle gears than the open diff design, I'm wondering if there is more gear slack due to the design that would cause the extra movement and BUMP noise in the driveline. My backlash is set at 0.0055" (at least that is what it was when I closed up the diff) so there shouldn't be any slop there that would cause the looseness. I don't have any gear whine or other types of noises while driving. Any thoughts would be appreciated. Thanks.
2006 Inferno Red SRT8 with groups I, II, Sunroof, K&N drop-in filter, Auto-dim mirror, Jet-180 T-stat, Predator, 300 SRT struts/springs, Chally SRT wheels.
Born 6-21-06, Home 4-26-10. 1/4 mile - 12.989 @ 108.78 in street trim. Traded in 10-19-2012.
2006 Inferno Red R/T with R&T Born 8-12-05, Home 8-25-05, Sold 8-9-10.
Possibly a loose drive shaft bolt or the lash wasnt set properly. Pretty much the only things it could be,
or center carrier bolts are loose.
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I've checked your suggestions and everything is solid. I had the car up on ramps and rotated the driveshaft by hand with the tranny in Neutral. The differential has more "slack" in it when rotating the driveshaft back & forth than my original open-diff setup has. I can tell the backlash is still tight because I can feel the tiny movement and click between the ring & pinion. The slack happens when rotating the driveshaft to transfer motion to the axle gears. In this type of differential design, I think there is more overall cumulative clearance between all the cross gears that has to be taken up when switching from forward to reverse before they lock to the axle gears. I'm waiting to verify this theory with Wavetrac.
Last edited by rodneyiii; 05-12-2012 at 02:29 PM.
Well after talking with an engineer at Autotech (Wavetrac manufacturer), I have removed my differential and sent the entire unit back to Autotech for them to diagnose. Once I got the thing out of the car and opened up the cover, I could see that the spiral gears inside the Wavetrac unit have a lot of play in them when I rotate the axles. There is much more play than the system should have and that causes the thumping when shifting gears or if I let off the throttle and get back into it. The thing scared me the other day because I was in low gear, let off the throttle, then slammed the gas to the floor at about 20 mph. Normally, I would start spinning the tires but this time the rearend slammed so hard that the engine pulled throttle on me. I guess the tranny detected something wrong in the driveline and killed the gas. After that, the diff had to come out before I was going to have any more fun in my car. If you can't beat on an SRT then why have it?
Between Autotech and Unitrax, I hope they can figure out what is going on.
Last edited by rodneyiii; 05-21-2012 at 03:07 PM.
Waiting for info from Wavetrac. The entire diff arrived there last Friday (5-4-12).
I definitely don't have anything like you discuss. mine is tight and has been flawless since i put it in. i only have one track day on it though. actually my deceleration lockup is pretty much before the decel condition exists. i'm assuming that is due to the good 0 load condition manors the diff has.
Well, I got an answer from Autotech today. They admitted there is more play in the Wavetrac unit compared to an open diff design but it was within the design specs. The engineer did say that the oil in the diff was very slippery and didn't wash away with normal degreasers. I used Wynn's 75W-140 gear oil. He had to phyically wipe the oil off the parts. That may affect the helical gear friction to create the power transfer to a slipping axle but it wouldn't make the overall gear slack any different. I'm not sure what to do but I'm inclined to get a refund on the Wavetrac and get a Getrag setup. Does anyone need a 215mm diff housing with gears? Any feedback would be appreciated.
Jontoad and Ponch79 - what oil did you put in your diffs with the Wavetrac?
Last edited by rodneyiii; 05-21-2012 at 03:07 PM.
What ratio are the gears?
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Please watch this video and see what you think. For those who have a Wavetrac or Quaife diff, let me know if this is normal behavior. Thanks.
The video plays better when viewed directly from the Youtube site (better frame rate). I don't know why since this is my first Youtube video.
Last edited by rodneyiii; 05-12-2012 at 02:56 PM.
Spoke with a friend of mine and he said.They didn't put enough shims in and made to much back lash.
I agree with ponch79 on the shim. There are three shims. One solid shim on the left and right sides for the carrier bearings. The pinion could be a single shim or a shim pack. I would blue the gears and check the pattern also. The first thing to go for would be the pinion shim(s).
Old 426 guy,
Some one screwed up!!!! There should be a few thousandths of movement. WTF!!!!