Lost drive to front wheels

[tercle]

looks like the ring and pinion gear set got trashed. I have seen it, but not that common. looks like you will be in the market for a new front diff assembly. If you can find the whole front diff/bell housing assembly that would be the best bet, you just swap them out. The Mark may have one that might work for you (not sure if the 2wd auto and the 4wd auto trans is the same diff ratio), presuming what failed in his trans is still good in yours.

The Mark may have one?
Mark?

[Mark]

That's strange. I wouldn't have suspected that the differential would fail like that without warning. I'd almost think that a bearing was worn causing the ring and pinion to not align properly. Either that or the oil in the differential was replaced with gravel. I just went out and counted the number of teeth on the ring gear of the 2wd auto differential I have sitting in my shed left over from my transmission repair job. It has 43 teeth (I only counted them once, but I think I got it right). It was too tricky to count the # of teeth on the pinion without marking them somehow. I don't know if the # of teeth on the pinion is standardized throughout the different models and the gear ratio can be calculated from the # of teeth on the pinion gear.

[Mark]

I just did a quick search on this forum and it says that all the models have 41 teeth on the ring gear and it's the pinions that have different #'s of teeth. I don't know how I got 43. I don't think I could have been off by 2. I had my finger on each tooth as I counted. I'll have to try it again later.

[Mark]

I counted again twice and still go 43 teeth on the ring. I counted the pinion teeth twice as well and got 12 teeth. That gives a reduction ratio of 3.583.

[tercle]

I found a mention of AT ratios in 2010.
https://tercel4wd.com/forums/viewtopic.php? ... ARD#p43381

The front and rear diff final drive ratio on the A55F automatic transmission for the Tercel 4WD is 3.909 as stated in the 1985 Factory Service Manual on page AT-17. The regular A55 automatic has a 3.583 diff ratio...

I checked page AT-17 of the 1985 manual that was mentioned, and it looks like the 4WD automatic has a 3.909 ratio and 2WD auto has 3.563.

[tercle]

If it's not one thing, it's another.
On my way to the chiropractor, the brake pedal almost went to the floor.
Massive brake fluid leak at right rear wheel.
Looks like it's the wheel cylinder.
Can't figure out which direction to move the adjuster to loosen - if I could find it and the adjusting lever.
Have to fix it quick tomorrow morning to get to work.

[dlb]

i always forget which direction it is too. i usually just go whole hog in one direction and if it gets to a point where it won't go any further and i can't turn the drum, i know i went the wrong way. only takes a few minutes to back it off anyway.

do yourself a favour and hit the union of the steel brake line and wheel cylinder with penetrating oil well before you do the job. also, i recently bought a set of flare nut wrenches for this sort of thing and wowee, they work great. a tip to make them last though is to get them in place on whatever nut you're working on and then put a pair of vice grips on the ends of the wrench. i was told that regardless of brand, flare nut wrenches will snap under any significant force without this.

[tercle]

I got the drum off.
Big hammer and blocks of wood.
The cylinder was leaking really badly, so I got the hard line off the cylinder (after soaking it with penetrating oil) and capped it with a short length of vacuum hose and golf tee.
Topped off the master cylinder.
My list for tomorrow:

1) brake cylinder
2) brake shoes
3) brake fluid
4) brake cleaner

thanks

[Petros]

likely you should replace or rebuild both left and right rear wheel cylinders. In my experience, when one goes bad, the other is not far behind. That is if they are both the same age, sometimes people will just replace one when it leaks, and leave the one that is not leaking (yet) to fail another day.

[Mark]

I found a mention of AT ratios in 2010.
https://tercel4wd.com/forums/viewtopic.php? ... ARD#p43381

The front and rear diff final drive ratio on the A55F automatic transmission for the Tercel 4WD is 3.909 as stated in the 1985 Factory Service Manual on page AT-17. The regular A55 automatic has a 3.583 diff ratio...

I checked page AT-17 of the 1985 manual that was mentioned, and it looks like the 4WD automatic has a 3.909 ratio and 2WD auto has 3.563.

I was just doing some light reading of my 1984 repair manual 4wd supplement for the A55F auto transmission and it says that the differential gear ratio is 3.727.

[xirdneh]

the auto tranny diff i worked on a few years ago was 3.73
i believe the car was a 83 or 84
there is a date of manufacture ( i think its nov 1984) that is the dividing line between 3.73 and 3.909

[c_j]

I got the drum off.
Big hammer and blocks of wood.
The cylinder was leaking really badly, so I got the hard line off the cylinder (after soaking it with penetrating oil) and capped it with a short length of vacuum hose and golf tee.
Topped off the master cylinder.
My list for tomorrow:

1) brake cylinder
2) brake shoes
3) brake fluid
4) brake cleaner

thanks

<hijack>
I was towing a boat last year downhill on the highway and had to make a hard brake application and I popped a wheel cylinder (pushed the rubber cup out). Not fun. Heavy on the e-brake and downshifting and pumping the brakes to try and halt before the red light at the bottom of the hill. My self-adjusters weren't even siezed, and I use my e-brake all the time, so there was probably a bad tooth on the star wheel, plus the brake linings were fairly worn. I would advise to clean and inspect that star wheel and and threads plus the lever that turns it.

As the story goes, I limped to the auto parts store at the next town using e-brake and downshifting and lots of following distance and proceeded to root through their brass fitting cabinet. This is what I came up with to temporarily plug the line (keep with your spares):
Weatherhead # 131x3 3/16" Inverted Flare Plug
Weatherhead # 1443 M10x1.0 Inverted Flare Male X 3/16" Inverted Flare Female Adapter
Weatherhead # 7934A M10x1.0 Inverted Flare Union
Plus the flare nut wrench (10mm) and vise-grips dlb mentioned.

Because I could not find a metric plug, we do this simple math:
combine: standard plug + metric adapter = metric plug,
then combine: metric plug + union = metric cap.

I would take a pic, but mine are in use right at the moment....
</hijack>