AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

General discussion about our beloved Tercel 4WD cars
swanterky
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My tercel:: 86 FWD converted from auto to 5 spd

AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

Post by swanterky » Tue Jan 29, 2013 11:25 am

I wondered, and theorized, why my 87 4WD will "lock" in 4WD mode and be impossible to shift back to 2WD after driving, even for a very short time, on dry surfaces. Having owned an '85 4WD Auto with a broken, and removed, crown gear in the front differential, and having been told by the seller that his uncle had driven the car on dry surfaces, I wondered as to the reasons for the differential failure, and why my current 4WD has to be backed up to disengage tranny from 4WD mode. I know that our tires must all be of an identical size, but this article explains the deeper reasons better than I can........

http://www.4x4abc.com/4WD101/def_turnpart.html

I have uploaded this virus free webpage in a compressed folder "4WD" in case it leaves the web for any reason, as it is very important for all 4WD Tercel owners to understand why they should never use (part-time) 4WD mode on dry pavement.
4wd.rar
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dlb
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by dlb » Tue Jan 29, 2013 12:31 pm

nice contribution! definitely a worthwhile read.

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ARCHINSTL
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My tercel:: Goldie is a 1986 SR5 attualmente con Weber/also owned the first T4WD in STL in late '82
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by ARCHINSTL » Tue Jan 29, 2013 1:59 pm

BRAVO!
Now a sticky.
Tom M.
T4WD augury?
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by Petros » Tue Jan 29, 2013 2:50 pm

Hah! I knew that. I learned in high school auto shop class, in the front end alignment unit, that each tire makes a different radius when you make a turn. Therefore, each wheel travels at a different speed. Hence the need for a "differential", so the wheels can travel at different speeds, and the diff "differentiates" the speeds between the inside and out side wheel. So a full time 4wd needs a center diff as well. I have written this before on this forum.

I can even tell this effect when in 4wd on gravel or snowy/ice roads, you can hear one set of tires slipping to allow the different speeds. When I really slippery ice is especially problematic where you have very marginal traction as it is. with one or more wheels required to slip in a turn it is possible you can initiate a slide on the ice. So it is always important to realize this necessary tire slip when in scary marginal traction situations.

I use the 4wd on pavement all the time BTW, as part of a diagnostic test; on straight hwys by slipping it in and out of 4wd you can help isolate drive train noises from either the front or rear drive train. Also, when starting in heavy traffice on a steep incline (lots of those in Seattle!), I will put it in 4wd, use EL, keep the car going straight ahead, and than when over the steep part, shift to first or second, than put it back in 2wd. On wet inclines in heavy trafic I will be either frying the front tires, frying the clutch, or stalled with the cars behind me honking agrilly at my Tercel. So it becomes necessary to use the 4wd to get the car moving on steep wet pavement. In all cases though I know I must keep the car going straight, the tires must be the same size and inflated evenly, and the alignment must also be proper (all suspension parts in good condition).

so it is not a "do or die" issue, but you must understand the limitations of being in 4wd vs. Fwd, being in 4wd doing a tight turn on a slippery surface can initiate a slide off the road since at least two of the four tires MUST slip in a turn.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

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dlb
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by dlb » Tue Jan 29, 2013 6:48 pm

Petros wrote:Hah! I knew that...I have written this before on this forum.
of course you knew that. we all did because we're all familiar with tercs. it's just good to have it at the forefront on the forum so that new owners who don't know it can learn it sooner than later.

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Funkybert
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My tercel:: 1987 Toyota Tercel SR5 wagon 4WD
Location: Seattle, Washington

Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by Funkybert » Wed Jan 30, 2013 2:24 am

Thanks Everyone!

I just bought my first Tercel... an '87 wagon.. and I am new to the info. about 4wd's... so this thread is actually perfect for me to learn about being careful in 4wd. I also live in Seattle.. so I completely understand what dlb is referring to and look forward to trying that method on steep inclines at a stop.

Side question: Any reputable shops in Seattle to help with some eventual big work on the Tercel?

Really looking forward to more inquires on this discussion board.. and meeting new peeps in the Tercel4wd world.. I'll get pics up soon!
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Petros
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My tercel:: '84 Tercel4wd w/extensive mods
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by Petros » Wed Jan 30, 2013 12:32 pm

Welcome to the list Funkybert!

Looks like a nice clean ride you have there. Where did you find it? I would not trust any regular auto repair business to work on these cars, most of the mechanics now have never worked on a car with a carburetor, big city auto repair is hard to find a good mechanic, they can shaft everyone that comes in the door and never run out of customers, and their overhead is really high. It is best on a car this old you do most of the work yourself, otherwise it get real costly for each old hose or seal that needs to be replaced.

There is a list member who lives in shoreline who does repair work on Tercels (and other vintage Toyotas) out of his home shop. I would trust Synth do do a good job for you when you need it. We also have Puget Sound area Tercel4wd meets several times a year, look forward to seeing you there sometime soon.
'87 Tercel 4wd SR5 (current engine swap project)
'84 Tercel 4wd (daily driver, with on going mods)
'92 Mazda MPV 4wd (wife's daily driver)
'85 Tercel 4wd DLX auto(daughter's daily driver)
'01 Honda Civic (other daughter's daily driver)

Gei1179
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My tercel:: Toyota tercel Station wagon 4WD 85'
Location: Zarcero, Costa Rica

Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by Gei1179 » Thu Feb 14, 2013 5:29 pm

:roll: Wao! que bueno saber de este tema , soy nuevo en este foro, de comprar Tercel 85`Station Wagon aqui en Costa Rica y no sabia sobre esto, gracias por la info.

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dlb
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by dlb » Thu Feb 14, 2013 6:56 pm

Gei1179 wrote::roll: Wao! que bueno saber de este tema , soy nuevo en este foro, de comprar Tercel 85`Station Wagon aqui en Costa Rica y no sabia sobre esto, gracias por la info.
"Wao! that's good to know of this issue, I am new to this forum, to buy 85 'Tercel Station Wagon here in Costa Rica and did not know about this, thanks for the info."

welcome, gei1179. not many members in costa rica. did you just get your tercel?

lurvemytercel
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My tercel:: 1988 Tercel Wagon AutoTrans 4wd
Location: Los Angels, CA

Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by lurvemytercel » Thu Mar 14, 2013 4:14 pm

That's the first thing I learned in my owners manual -- never switch on the 4WD on a dry road. I've been super careful about that since I bought the car new in 1988.

I do notice, when I have the 4WD switched on (when it rains and roads are slick), that when I make sharp turns such as backing out of parking space, the car doesn't move smoothly -- it feels jerky -- always has. Is this normal for the 4WD wagons when you have the 4WD switched on?

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dlb
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavemen

Post by dlb » Thu Mar 14, 2013 4:56 pm

yes it is, lurvemytercel. if you can feel that, you should disengage the 4wd because it means the diff is binding up. even though the roads are slick, the tires still have too much grip and end up fighting the diff. it's fine in tiny doses but not something you want to make a habit of since it could do serious damage to the diff.

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drege
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

Post by drege » Tue Mar 17, 2015 10:34 pm

I obsessively look at my shifters even though I know what 4WD feels like, I eyeball it every time I release the parking brake - too great a chance it could have been put in 4WD and something breaks.
It takes more fossil fuel resources to produce new vehicles than it would take to maintain and fuel any 70's or 80's vehicle for a million miles.
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irowiki
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My tercel:: 1987 Tercel Wagon FWD
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

Post by irowiki » Tue Mar 17, 2015 10:48 pm

Your 4WD light burned out?
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drege
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

Post by drege » Wed Mar 18, 2015 4:30 pm

I never rely on dummy lights.
It takes more fossil fuel resources to produce new vehicles than it would take to maintain and fuel any 70's or 80's vehicle for a million miles.
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pordog65
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Re: AN IMPORTANT READ! Why never use 4WD mode on dry pavement?

Post by pordog65 » Tue Mar 31, 2015 11:43 pm

Good reads.!

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