Need help with torque steer., Searched, searched more, searched again, gave up. Options

[richee3]

I've been pulling my hair out over this issue for several months. I can't figure out what it is. I'll start with the background details.

I have the factory LSD S54 tranny on my BEAMS. Never had any issues out of it. However, bloodMoney noticed a droning noise related to my gearing that I hadn't noticed. It started only on slow acceleration, where I usually accelerated quick enough that I flew right past the noise and never heard it. This slight issue has never seemed to be anything more than just a noise, but now is in all 5 gears, pretty noticeable up until 3,000 rpm when it suddenly goes silent. Not sure if it's related to the torque steer at all. It makes a wah-wah-wah-wah-wah-wah noise, similar to that of old worn out tires. It needs to be said that when I turn the wheels and hit the throttle, my wheels are locked together and turn just like they should. Absolutely no issues when I turn, just when I'm going in a straight line.

Last summer, I replaced my front lower control arm bushings for poly bushings, new Racing Beat rear end links and Two's R Us front end links, Moog ball joints, and more importantly, bought Dustin's ADR Vision rims with 225/45/17's and coupled them with 10 mm spacers. The front end links, rims, and spacers came last, in that order. Some time after installing the rims and spacers (not sure how long, it was a month or two) I noticed if I accelerated hard, the car pulled right. Let off the gas, it would straighten back out, meaning it pulled back to the left quickly. Eventually, it became any acceleration at all, hit a pretty good bump and it would go to the right, but if I was just cruising or decelerating, no issues at all. Only on acceleration. Typical torque steer.

Late February or early March, I picked up Noberto's 17" Caldina rims. They're just a little bit lighter with 215/45/17's. When I swapped rims out, I noticed a badly torn passenger side axle boot. Problem found, I thought. Drove with the Caldina rims a few times while waiting for a pair of new axles to come in, and I immediately noticed that torque steer was greatly reduced, but still present. Now it only pulls in 1st-3rd gears. The high gears are relatively trouble free. I got under the car, replaced both axles, and thought I was ready to rock and roll. Wrong, problem was still there.

I've put entirely too much time into this and come up with nothing. I've had a few theories, including worn out LSD. I'm aware that helical LSD's do need to be rebuilt around 90,000 miles, which is close to what mine has on it. However, a worn out helical diff acts like an open diff and does not do anything like what mine is doing. So I thought maybe something in the suspension was loose. Wrong again, it's all torqued to spec. Motor mount issue, maybe? Perhaps my motor was able to twist around on acceleration? Nada. My motor mounts, while not brand new, all pass a visual inspection. No cracking, all bolted down tight, and I can't get the motor to move when I try to force it around. So I gave up on actually looking at the car and resorted to teh intarwebz. The only thing I could find is possible due to wheel offset. It's very possible, since the issue started some time after installing the spacers. I don't know the offset of the ADR Visions, but I know the offset of the Caldina rims is +45 so I'm currently at about +35 offset. Plenty of Celicas running around with +35 and no issues. I'm at a total loss here, I give up. Anybody have any suggestions? I'm all ears.

This post has been edited by richee3: Apr 15, 2013 - 1:55 PM

[richee3]

I think the stock LSD isn't helical, which doesn't "wear out". I think you meant clutch-type, or viscous. Those do wear out.

Did you make sure the input and output shaft bearings were good? Are your other two mounts good?

I do definitely have the OEM helical diff. I know OBX helical diffs (which suck) wear out and need to be rebuilt, and I've found a nugget of information (sadly, from Wikipedia) that says that helical diffs technically need to be rebuilt, and they begin to act as open differentials. Nowhere does any source say that I should get anything like I am. I'm not even sure my torque steer is related to my diff. The diff seems like it could be working perfectly and something else is causing this, but then the same could be said of all other steering/suspension components. Input and output bearings are good, as are all four motor mounts.

It needs to be said that when I turn the wheels and hit the throttle, my wheels are locked together and turn just like they should. Absolutely no issues when I turn, just when I'm going in a straight line.

That sounds like the opposite of what it should be doing.
It should lock when your close to going straight, or going straight, and slip when cornering.
You shouldn't be getting any "torque steer" with the LSD .

That's exactly what gets me. I didn't have any torque steer with the LSD and stock rims/tires. It didn't start until I bought Dustin's ADR's and spacers, and got a little better when I switched to Noberto's Caldina rims. However, the noise that I get up until 3k RPM started last summer and has since gotten louder, so I suspect my culprit has something to do either with that humming/droning noise or something to do with the spacers. However, plenty of members here have +35 offset with no issues, with or without spacers. I'm totally stumped. I appreciate any and all help, any pointers, tips, etc.

It should be noted that my gas mileage started decreasing when the noise started, going from 33-34 highway down to 26-28. So I'm probably getting some rolling drag resistance somewhere. That's another thing that makes me suspect LSD. I used to have a couple of spare S54's sitting around but I've sold them off, so I can't exactly swap those out to test out that theory.