97pontta

iTrader: (10)

I just fished my mild engine build and the fist time at the track my 6 year old Tru-Trac is clunking and making very loud noises when turning. I can tell something isn't right as it also jerks when going around corners like it's a locker.

I want to upgrade to a stronger differential later this year as I am also planning on changing my rear gear ratio from a 3.89 to a 4.30. The car is mostly street driven and a little road racing so I need a differential that transmits power as smoothly as possible. I my best bet the Wavetrac unit?

Also, I run a McLeod street twin and a T56 if that matters at all.

ssvert99

iTrader: (26)

Being you have a Truetrac with 31 spline axles the Wavetrac will be your best option for sure, especially considering your power level and the M6 trans.

Give me a call... I can set you up with the diff unit and the rest of the small parts required to do the job and the guaranteed best price.

Guitar

iTrader: (9)

The Wavetrac is nice but really expensive, and at that point I'd just go 35 spline and get it out of the way, adding more cost. Your plans might be different of course, but. I have the Truetrac and it is surviving a beating at the dragstrip in a heavy car and feels just like stock basically.

97pontta

iTrader: (10)

Thanks for the info gusy, I plan to stick with the 31 spline axles as I don't plan to increase the power level of the car (31 spline should hold up fine at my power level I think) and less weight is better. The price of the Wavetrac isn't a problem, I just want a replacement that is stronger and will hold up to the abuse I plan to give it with manners that will work on the road course.

Now my other question is at a 4.30 gear ratio, which gear manufacturer has the best reputation for quiet gears? My 3.89 gears have always been really loud from day 1, it's so bad that driving around with the windows up you need ear plugs if the drive is more than 10min. Like I mentioned earlier the car is mostly street driven and road raced, with a few trips to the 1/8th mile thrown in a few times a year so I don't think I would need a race cut gear for strength at my power level would I?

ssvert99

iTrader: (26)

Motive Performance series and the Yukon gears are the best as far as I am concerned. Unfortunately any street gear, any brand, in a 9" rearend in a f-body car with a torque arm will resonate the noise of the rearend, suspension, and tires into the car worse than any other.

You need the 8620 alloy "street" gear. The softer 9310 alloy "race" gear will wear out quickly on the street.

97pontta

iTrader: (10)

Thanks, I sent you a PM.

I understand some noise comes with the larger rear and rigid suspension components but I figured it would be tolerable. I'm pretty noise tolerant as I work in a loud environment every day for the last 15yrs but I actually need to wear ear pugs on long trips due to the high pitch rear end noise if the whether doesn't allow me to open the windows.

96lt4c4

iTrader: (5)

What brand gear is in the rear end now? I just burnt up a brand new Yukon gear in mine 3.89 ratio that started off quiet. I think it was my fault, got on it a little to early. I took it out on the very first test drive, 15 miles, I had a lady going really slow in front of me, when she turned off I put it up into third and just barley rolled on it. When I let off then got back on the gas it was whining, real bad sinking feeling in my stomach I put about 200 miles on it and the noise stayed the same. Then I took it to LS fest and beat on it pretty good on the autocross track. On the drive home she was really sounding off. Luckily I had a friend there with an empty car trailer.

The gear I am replacing it with is a Motive Performance 3.89. I got it setup last night. This gear seemed to setup very easy. I am running a billet Trac Loc. It may not be the best for drag racing, I dont know, but seems to do really good on the autocross track, and the street. I do not know how much power they will handle before they burn the clutches out.

As far as that gear burning up goes, I have setup multiple 10 bolts with the Motive performance ring and pinion. The last one I put together for a friend of mine. The first time he pulled it out of the drive way he dumped the clutch and blew the tires off. His is still quiet to this day. I did the same thing to my 10 bolt and never had a problem, until now the torsen posi **** the bed, but the gear is still good.

I am going to run some extra oil in my 9 this time to help with the heat, and make sure I baby it for the first 500 miles.

Also why are you going from a 3.89 to a 4.30? I had a 4.10 in my 10 bolt once and hated it, to much shifting on the street. It would be better for the 1/8th mile though.

97pontta

iTrader: (10)

I have Yukon gears in it right now, a local gear shop installed them back in 05. I did the proper break in procedure and it has wined from mile 1 and hasn't changed for better or worse even after years of abuse.

I'm wanting to go to the 4.30 gear for a few reasons. I do mostly highway driving and with the 18" rims in the rear and a taller street tire I don't get into 6th gear until 75 mph without lugging the engine. And when I do drive the interstate I still will be under 2100 RPM at 75MPH which I'm fine with as I live in BFE Iowa and don't drive the interstate much.

I also do some 1/8th mile drag racing and a 4.30 would be a perfect fit for my MPH and shift points. Currently I'm shifting at 7000 RPM and cross the traps at 6100 so the extra gear would allow me to use the power the best as I should be crossing the traps around 6800-7000 with the 4.30 gears.

96lt4c4

iTrader: (5)

I just drove my car last night with the Motive 3.89 in it. It is very quiet, makes a little noise around 40-45 MPH. I put about 10 very easy miles on it, only got up to about 55 mph. So far so good.

97pontta

iTrader: (10)

Thats good to hear. I'm going to look into Motive. I'm OK with a little noise but mine sounds like a jet landing