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Disco Dan
07-12-2005, 02:23 AM
Ok, so today I decided to further diagnose a problem, mainly a knocking/rattling sound that occurs when driving at certain speeds with the wheels in the straight-ahead position. In the process, I put the car up on jack stands to see if I could identify any visibly loose parts. I did notice that the front bracket/clamp and second brackets had rusted through, but pushing on the exhaust pipe didn't seem to recreate the noise.

In any case, while I had the car up on jacks, I decided to turn it on, to see if it would make the noise when the wheels were straight. Since it's front-wheel drive, I was able to let the wheels spin freely in 1st gear without worrying about it slamming into the curb, etc. However, while the wheels were up in the air, I couldn't recreate the noise.

It was about this time that I noticed something really strange.

The only wheel turning was the driver's side wheel.

The passenger side wheel seemed to be budging in tiny intervals, like it was sometimes gripping, sometimes not, but it definitely wasn't spinning consistently. Now, I seriously doubt that Toyota would call a car a 2- wheel drive car, when power is only going to one wheel. But maybe I'm missing a basic fundamental of the front wheel drive transmission/axle system, but I was under the impression that BOTH wheels in the front should be turning. Then again, maybe it only does that under the pressure of the weight of the car. I'm not sure. But it's a bit disturbing. Now I'm wondering how long I've been getting power to only one wheel.

I'm afraid I'm going to have to just break down and take this one into a shop and have them diagnose it. I hesitate to do that because shops tend to find more things wrong than are really big problems. That, and labor charges add up. I'd rather not drop a thousand dollars right now if it can be helped. Actually, I can't afford to do so, so it's not really about what I'd like to do, but more about what I can do.

I don't know. I'm getting that dread gut feeling that this car isn't going to be worth the hassle. And it's only got 80k original miles on it. I really don't want to give up on it yet. I don't know.

Comments? Questions? Suggestions?

D

Hooligan
07-12-2005, 02:39 AM
The one wheel turning is thanks to the open diff, but I don't think that's overly normal. How are your wheel bearings?

Punisher
07-12-2005, 02:45 AM
Let a garage tell you what is wrong.. you fix it yourself. Labor goes into all of the time spent fixing the problem.. Diagnosing it shouldn't take more than an hour or two max.. so you are lookin at somethin like 80-120 bucks..

As for the one wheel.. that's right.. A non-LSD (limited slip differential) FWD transmission is like that.. That is why we get torque steer.. Ever slam the peddle down and when the gear shifts you can feel the steering wheel yank to the left? Because that wheel is the one basically getting all of the power.. An LSD tranny will net you the same power on both wheels except when you turn.. Then the passenger wheel will lose power (slip) so that you can get a tighter turn radius and not break anything in the driveline.

Disco Dan
07-12-2005, 03:01 AM
oh holy crap that's a relief. Here I was thinking "omg the transmission gears are stripped and the passenger-side wheel isn't turning." Spazzed for nothing, I guess. The bearings are actually fine as far as I can tell. No audible noises.

Thanks for the suggestion on the diagnosis, Punisher, I think I'll drop it off at a shop near work tomorrow, to see what they can find.

And now I'm going to go to howstuffworks.com and read about transmissions and differentials. Thanks again for the headache-saving advice!

D

Hooligan
07-12-2005, 03:12 AM
Let a garage tell you what is wrong.. you fix it yourself. Labor goes into all of the time spent fixing the problem.. Diagnosing it shouldn't take more than an hour or two max.. so you are lookin at somethin like 80-120 bucks..

As for the one wheel.. that's right.. A non-LSD (limited slip differential) FWD transmission is like that.. That is why we get torque steer.. Ever slam the peddle down and when the gear shifts you can feel the steering wheel yank to the left? Because that wheel is the one basically getting all of the power.. An LSD tranny will net you the same power on both wheels except when you turn.. Then the passenger wheel will lose power (slip) so that you can get a tighter turn radius and not break anything in the driveline.

This is partially correct. Torque steer is due to the shafts being different lengths. One rotates further under the same amount of torque due to its additional length. Also, open differentials put the same amount of torque down to both wheels, which is bad if one is spinning freely. Limited slip differentials are just that, they allow some slip in the inside wheel in a turn (or faster turning wheel when in a straight line) before power is transferred to the other wheel (how much depends on the torque bias ratio).

I am pretty sure that both wheels should turn when they are in the air. Is it possible that you have a sticky caliper?

Disco Dan
07-12-2005, 03:18 AM
Actually, that IS possible. I know the brakes are in dire need of attention. I've just been putting off breaking down and doing the whole lot of them. The pads are gonna need to be changed, and the rotors may need some attention as well. A lot of what's wrong with the car is stuff that the previous owner(s) were lax about and now I'm cleaning up their collective messes. But the sticky caliper thing is possible. My main worry was/is that there is some gear not making a solid connection to the right axle, but my knowledge of how that part of the car works is minimal. Either way, I'm gonna take it in and see what the shop says. I think I won't mention this part and see if they say it's a problem of their own accord, without the suggestion from me. We'll see! (That rhymed. Unintentionally so.)

D

Slider
07-12-2005, 03:18 AM
All the power usually goes to the wheel with less resistance, but with both wheels in the air, they both should be turning I believe, altough I have never tried it.

Disco Dan
07-12-2005, 03:26 AM
Actually, yeah, if anyone else could test their Celica with the front wheels off the ground (all trac users: this would not be a good idea) to see if both wheels spin equally or not, that would be great. Granted, getting the car up on two jackstands is not a quick task, so there's no rush there.

D

Dr Tweak
07-12-2005, 03:30 AM
It's totally normal for only one wheel to turn. It's an open diff.

Also, that statement about torque steer is not correct, a limited slip will make torque steer MUCH worse because most of the power is going to the wheel with the MOST traction, vs with an open diff. If you don't believe me, try driving a car that has a Quaife sometime... mash the pedal and HOLD ON TO THAT WHEEL! HAHA :cool: :bigthumbu

*edit* Clarification on the above, there are two types of LSD, and LSD and an ATB (automatically torque biasing), the only type of LSD you should EVER use on a FWD car is the ATB (like a Quaife).

fiveSFE
07-12-2005, 03:56 AM
back in the day only one wheel spun on my celica

Disco Dan
07-12-2005, 04:22 AM
ok after reading through first the clutch section, then the transmission section, and finally:

http://auto.howstuffworks.com/differential.htm

I see why only the one wheel was turning. Through necessity of the forward motion of the car on the ground, both wheels would be receiving power, changing as I turned to the right or two the left, but there would be nothing to really turn the passenger side wheel, nor any need for it to turn if they're both in the air.

howstuffworks.com is awesome. Seriously, in the last hour I've learned how a transmission, clutch, and differential work. Now we'll see if I can remember any of it in the morning...

D

xeril
07-13-2005, 06:09 PM
wow, you live close to me and 96celica ;) we're both up nearby the patriot center. if ya ever need any help, let us know..

Galcobar
07-14-2005, 12:14 AM
Disco -- your rattle is quite likely your exhaust.

I had the most annoying rattle going on it seemed coming from the area where I'd just installed my new receiver. Tore the car apart looking for it, until I finally figured out how to make it do it continously. Put the e-brake car, threw the car into reverse (auto) and away it rattled. The exhaust hanger at my resonator had broken, and at certain RPMs, the stumps were bouncing off each other.

The trick was, pushing on it didn't make the noise. I was only able to diagnose it by gripping the pipe itself and discovering the rattle immediately died. The distance between the stumps wasn't big enough to see or make noise unless I pulled up and down on it.

Disco Dan
07-14-2005, 01:36 AM
Unfortunately, to replace the exhaust hangers, I'm gonna need the entire front exhaust, since the parts that have rusted through are attached to the pipe itself, not on the brackets. The parts rusted are shown below. One of them is a separate piece, but the other is part of the pipe itself:

http://discodan.org/gfx/celica/exhausted.gif

Thing is, the rattling sound is more solid-sounding, but I'll still get those parts fixed just in case. Anyone got a cheap front exhaust pipe they wanna sell me?

Good to know there are a couple of people from the area here! I'll probably make use of that invitation before long! Actually, I work in old town manassas, so I'm even closer than that.

D

ray_sir_6
07-17-2005, 12:44 AM
The one wheel turning is thanks to the open diff, but I don't think that's overly normal. How are your wheel bearings?

Yup...open diff...if you grab the one that is spinning, it will turn the other one.

GT4Dreams
07-18-2005, 10:15 AM
Don't know if you really want to grab it but...

As for brakes, I got a very nice, solid, brand name, and most of all, inexpensive setup for my 91 mr2. I got my solid brake rotors/discs from napa, all four of them for $75, and I got axxis ultimates in the back and deluxe in the rear, all for $80. I put them on and they are such a vast improvement. Has an awesome pedal feel, and "control" so you know when you are about to lock up the tires.

Here is the website where I got my brake pads. http://www.importrp.com/home.php
I beleive I dealt with Mike there, they did an awesome job order.

ray_sir_6
07-18-2005, 04:53 PM
[QUOTE=GT4Dreams]Don't know if you really want to grab it but...QUOTE]

Well, it's idling on the jackstands, and only one wheel is turning, so if you apply resistance (yes, using your hand will work, had fun doing this when I replaced the axles a few yrs ago) to one, it will transfer the power to the other wheel. Hence OPEN dif.

Rayme
07-18-2005, 10:27 PM
I did that with my car one time and only 1 wheel spun. My car is ok, juste means you have more resistance in either wheel.

GT4Dreams
07-25-2005, 07:05 AM
oh ok, in my head I pictured the wheel spinning then you trying to grab it and busting your hand all up me=idiot