Manual transmission wiring questions

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trailerparkzero
Member
Posts: 35
Joined: Fri Jan 11, 2013 11:11 pm
My tercel:: 1983/85 halfbreed and a beastly 84
Location: San Diego, CA

Manual transmission wiring questions

Post by trailerparkzero »

New owner of an 85 here. I'm waiting to get the pink slip and its official before I show her off to you guys but i couldn't wait to start fixing everything i'm capable of.
The first time I had it on the interstate i noticed it had a louder gear noise then I would expect. Sounds kinda like your in reverse. The noise is only there when you touch the gas not when coasting. I figured i better check/change the gear lube as a start. Looking up at the trans under the car I notice a wire hanging down the side of it. I follow the wire with my hand and an electrical connecter with some mangled wire falls off in my hand.

A mouse has chewed the hell out of the wiring for the reverse, 4wd and EL indicator. All kinds of copper is exposed on each of the 2 remaining connectors.

Can I unscrew these switches while the trans is still mounted?
Make this a lot easier if i can build a new harness and install it rather then trying to build one into place.

What does the 4wd solenoid do? ( I think its 4wd sol, FSM wiring digram is cut off. all you can see is wd solenoid)

Any help will be great i will need to get the reverse lights working again to get it to pass the CA inspection and I need my 4wd in top shape so I can take it camping in baja.

I might add that the gear noise is possibly gone as i have not test drove it since I reattached a loose vacuum hose.
MR2Di4
Advanced Member
Posts: 77
Joined: Fri May 05, 2006 1:06 am
My tercel:: 1985 SR5 4WD Wagon
Location: Ketchikan, Alaska

Re: Manual transmission wiring questions

Post by MR2Di4 »

The wiring actually does nothing at all as far as 4WD functionality goes. As you've suspected, the wiring just goes from switches that complete the circuits for the indicator lights you've mentioned. You may be able to get better access by removing the rear driveshaft and unbolting the rear mount to let the transmission come down enough for better access to the wiring and connectors. The harness is secured to the transmission and body by bolted clips that once undone will probably give you adequate slack for a splice or two. The switches themselves are plunger switches that simply unscrew from the transmission, depending on how much space to work with you have, it shouldn't be too hard.

MR2Di4 8)
'85 4WD SR5 S/W (Winter Daily Driver)
'88 Toy Truck (Summer Daily Driver)
'86 4WD AT S/W (First T4WD, long gone...)
'88 MR2 N/A (Namesake College Car, also long gone...)
'70 AMX (Family Heirloom, will never be gone...)
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dlb
Highest Ranking Member
Posts: 7447
Joined: Mon Jul 06, 2009 9:03 pm
My tercel:: '87 sr5, '83 dlx parts car
Location: bc, canada

Re: Manual transmission wiring questions

Post by dlb »

TPZ, great name. if your terc is an SR5, that means it's a manual transmission, in which case it does not have a solenoid. there were some automatic trans DLX's (the lower trim level) and i believe their 4wd was activated via a solenoid but am not positive. so as mr2di4 pointed out, that wiring is just for the dash indicator lights.

interesting about the loud gear noise that is only present when giving it throttle. if it's really only there on throttle, i think it's more likely in your exhaust. maybe check the exhaust/intake nuts and bolts and make sure all are snug, check the donut gasket where the exhaust manifold meets the exhaust head pipe, and check the entire exhaust pipe for holes.

always a good idea to replace the trans and diff oils on a car this old too, though. if you see some gnarly metal chunks, it might be bad transmission news.

the first thing i thought of when you said "louder gear noise" was a bad wheel bearing, but again, if it's only there on throttle that doesn't sound likely.

keep us posted, and good luck.
trailerparkzero
Member
Posts: 35
Joined: Fri Jan 11, 2013 11:11 pm
My tercel:: 1983/85 halfbreed and a beastly 84
Location: San Diego, CA

Re: Manual transmission wiring questions

Post by trailerparkzero »

dlb, You were right. The whole time my car has had problems it's been the main exhaust/intake manifold gasket. the I snapped one of the bolts that bolts the intake to the exhaust and when I took them both off to fix it I found it was leaking on the bottom the whole time. The manifold bolts seemed tight but I guess they were just frozen in place loose, if that makes any sense? You can see carbon on the engine from where the manifold was leaking. I got a new gasket as the one in was crusty and rusty and I am trying to find some new bolts before I put it back together.

Does anybody know where to find the gasket that goes between the intake and exhaust? I cant find it anywhere. Could I get by with a little high temp sealant? What kind? the gasket is little rusty like the one on the mani.

I hope I didn't drive my car into the ground driving it like this. i've put about 3,000 miles on it since I started this post.
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