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]

Nope, I know the clutch-type diffs need to be rebuilt. My only source of info for helicals ever needing to be rebuilt are Wikipedia (poor source, I know) and some Honda forums where those guys say that they installed OBX diffs and something broke so they had to rebuild them. TRD actually made both a clutch-type and helical diff that will fit our cars, took me a while to figure out that they made two different kinds there. Anyway, my LSD itself seems to lock the wheels together just fine when I turn the wheels and take a stab at the throttle, which shouldn't happen if it was actually worn out. My LSD may very well not have anything to do with my torque steer issue. I'm just coming up with theories then trying to research them, which is turning up with nothing. Basically, all I've found is that wheel offset can cause torque steer (which I'm nowhere near that point, +35 is fine on a Celica) and then I figured my LSD may be acting up and transmitting more power to the driver wheel, causing me to steer right when I accelerate. I'm not ready to take the car to a shop to let them cruise around in it just so they can start making up problems and replacing things only to make no headway, yet I'm out of ideas of what could possibly cause a motor with only 154 ft lbs of torque and no previous history of any such thing to do this.

Brian's theory of a wheel bearing does hold some water, I can see where a wheel bearing not rolling freely would cause this, but it should affect me at cruising and deceleration just the same as acceleration, but the car tracks straight and true when I'm cruising or slowing down. When I turn the wheels, the issue disappears as well. It's only in straight lines.

The only things I've changed are the poly control arm bushings, Twos R Us front end links, Moog ball joints, wheels, and spacers. So the issue could potentially lie in the offset, bushings, or in some component of the drivetrain. I hate to start throwing money at this issue until I have a pretty good idea of where to start, but I am truly stumped. The car is perfectly drivable, but this is definitely a nuisance and robs a lot of enjoyment from driving the car. I guess I'm still another three weeks without the car anyway, so plenty of time to brainstorm.

Edit: bloodMoney and alltracNyx have both heard the humming noise from my car (they were actually the ones that heard it and pointed it out to me) and they did some research. They found something that alludes that some older Toyota trannies do make a humming noise and that it's no big deal, they keep working just fine. The only difference between my JDM S54 and the USDM S54 is the helical diff and my final drive is 4.18 vs the USDM 4.176. So there's no real reason that it should be any different than a USDM S54, but I suppose the LSD has close to 100,000 miles now and could just me making a noise and nothing else wrong. I don't know, I'm pulling my hair out trying to figure out what the noise is, why the car pulls, and if they are even related.

This post has been edited by richee3: Apr 28, 2013 - 4:34 PM