markjs

Do I need any special tools. How do I recognize different gear ratio diffs?

toy283

Are you asking about swapping third members or swapping gears in the third member you have?

The first option is definately easier. No special tools required other than maybe a 10mm flare nut wrench for the brake lines and a jack and jackstands. Essentially, you just pull the axleshafts, remove the driveshaft from the pinion and pull the diff. Installation is exacly opposite. Should take a novice 5-6 hours tops. Experience can knock it down to an hour or so.

The second option is quite a bit more involved and requires a few special (and sometimes expensive) tools: a bearing press, dial indicators, two torque wrenches, etc. This is of course is after the differential is removed so you need all the stuff from above as well. A good gear setter should be able to do it in a couple hours, an inexperienced one may take all day to get it right. Setting gears is not for the mechanically squeemish, a bad setup can end a gearsets life very quickly.

Somewhere there is a guide for pinion paint codes. Supposedly, Toyota painted the end of the pinion a color code that tells what ratio it is. I've never seen it but I've never paid any attention either. If not, you could always count pinion and ring gear teeth and do the math:

Ratio = number of ring gear teeth ÷ number of pinion teeth.

4.10 ratio, the most common ratio for Toyotas is 41 ring gear teeth ÷ 10 pinion teeth = 4.10

Flygtenstein

If you mean pulling the third, then you need 2 jack stands, a 10mm flare nut wrench, I want to say a 12mm and 14mm ratchet, 24mm ratchet for the drain plug and two 14mm box end wrenches.

Jack up truck.

Place on stands.

Use wrenches to disconnect driveshaft.

Use flare nut wrench on hard brake lines to remove and cap.

Pop off brake drums.

Disconnect e-brake cable.

Use ratchets to disconnect backing plates.

Pull out each side axle.

Use ratchets on the studs holding the third.

Pull out third.

Be carefull of the inner axle seals and consider having new ones on hand if you bugger them.

markjs

Whao! Hold the trucks. I am a novice and I have no idea what a "third" is. All I know is I was told if I wanted to make my 1981 SR5 Longbed have a little more power in high gears that I might make to make the gearing a little shorter. I gather from what you said that changong the diff should be easy anoug but what I need to know is if I go to a junkyard how am I going to know which differential to buy?

fourwd1

A "third" is short for "third member", which a term for the removeable differential in Toyota axles. You're wanting to change gear ratios, which does require removal of the 3rd member. A gear swap is not a job for an amateur, much less a novice. It requires specialized tools and much experience to set up a R&P (ring and pinion gears). Also you can't just change the rear 3rd in a 4WD truck, you must do the front also. Figure approx $800 for parts and labor.

If you're going the junkyard route, you can determine the vehicles R&P ratio by decoding the plate on the firewall using one of the charts available on the web. I'm sure someone will chime in with a URL.

4.30, 4.56 and 4.88 ratios are available in Toyota 4X4's, but may be hard to find.

markjs

This is a 2wd model and the problem is that I have no real power in 5th gear. I can get her up to 70 and maybe 80 in 4th but no balls at all in 5th....Basically if I am already cruising fast in 4th on the flat I can shift up to 5th and cruise ok but the minute I hit a hill its back down to 4th. I just want more pep in 5th gear. The truck is stock as is.

Yoda

What year/model truck do you have?

Todd E

What year is your truck?
Engine, tranny?
Finally, take a look at your vin plate - either on the drivers side door frame or under the hood directly over the engine, depending on the year (they changed it in 88 I think).
You'll see a code "A/T" standing for Axle/Transmission
After that will be some codes like "F302/A43D"
That's the code on mine.
It came with 3.73 gears - 7.5" ring gear - and an automatic transmission.
If you have a v6 it should say "G382/R150"
Here's a page that you can use to decode your axle code.
Post back what you find.
If you do in fact have the "Fxxx" code, I have my origional axle out of my truck and I could send you my origional 3rd. My guess is I have a lower (higher number) ratio than yours does stock.
Let us know what you find.
Todd

markjs

The only thing on the door plate that says "AT" says 32 PSI after it and goes on talking about the wheels. It's a 1981 SR5 2WD 22R engine and all I know about the tranny is that it's a 5 speed

Todd E

OK, for that year, the vin plate is under the hood on the firewall, directly above the engine.
It will have 3 different lines of characters, the first is your VIN, the second is your specific model, the third is your color, trim, axle, and transmission codes.
They are all run together - not seperated by slashes, etc. - so if you don't know what to look for it can be a bit confusing.
The second image on that page I linked should be similar to what yours looks like.
Mine is the same way. It wasn't until 1989 that Toyota put the vin plate on the door jam.
Let us know what you find.
Todd

markjs

That's just it! It's very clearly on the door sill, and not inside the hood. I will make a full transcription of it and get back to you

markjs

As I said it's on the drivers side door sill, and here is the complete transcription of what it says

MFD. BY TOYOTA MOTOR CO. LTD.
OCT./80
GVWR (LBS/KGS) 4100/1860
GAWR (LBS/KGS) FRT 1850/840 WITH ER78 - 14 (B) TIRES
14X5 1/2-JJ RIMS, AT 32PSI/220KPA COLD
RR2540/1152 WITH ER 78-14 (B) TIRES
14X5 1/2-JJ RIMS AT 32PSI/220KPA COLD
THIS VEHICLE CONFORMS TO ALL FEDERAL MOTOR VEHICLE SAFETY
STANDARDS IN EFFECT ON THE DATE OF MANUFACTURE SHOWN ABOVE
VEH. IDENT. NO. : JT4RN4451B0008364
VEH. TYPE : TRUCK

I have THOROUGHLY searched on the firewall and there is nothing even resembling an identification plate, and no sign at all that there was one that was removed. Underside of the hood has the emission sticker and the vaccuum map, but thats it for tags under the hood.

I was told the only other way to determine the gearing is to put the truck on jack stands, and turn the wheel one revolution while counting the rotations of the driveshaft

markjs

One thing I know for sure, is that the differential is posi because when I jack up one wheel it won't turn.

Shane

Parking brake off, tranny in neutral? Just checking the obvious...

Shane

My '86 must be ahead of it's time then... The b-pillar plaque has always been VIN number, manufacture date, and tire info. The other main plate is supposed to be centered on the firewall and has paint code, body trim, engine/tranny configuration etc and VIN. Mabye his is missing or they didn't put it there back in '80, but I thought they did.

toy283

It should be on the firewall.

markjs

DOH! duh I didn't take it out of gear LOL....It's NOT posi.

markjs

I may have found what I am looking for! I was so intent on searching the firewall I missed the tag on the inside of the passenger side fender. It reads as follows:

TOYOTA MOTOR CO. LTD.
ENGINE 22R 2366CC 144.4 CU. IN.
T4RN44511B008
MODEL RN44L-MSA
C/TR A/TM 474FA41F302W50

According to the chart on the link Todd E gave this is the code I needed but it doesn't show what it means on that chart.

toy283

The last line of what you have posts the codes:

C/TR A/TM 474 FA41 F302 W50

The first part is just a guide, the second parts relates to the first. It tells the sequence of listed codes:

"C" = Color (paint) code, useful if you need touch-up paint
"TR" = trim (interior) code
"A" = axle code
"TM" = transmission

The second part:

"474" is the color code
"FA41" is the trim code
"F302" is the axle code
"W50" is the tranny. Not really a code, it plainly tells what the tranny is. This is the most puzzling part if you ask me, I didn't think W series transmissions were used until later. I would have figured a L or G series in '80/'81.

To decipher the axle code, go here.

F302 breaks down as follows:

F = 7.5" ring gear
30 = 3.727:1 ratio
2 = 2-pinion

So, you have a 3.727:1 ratio. Clear as mud?

markjs

So let me further show my ignorance and ask: if I am looking for more pep in 5th gear do I need a higher axle ratio? Isn't 3.727:1 rather tall? Don't I need something shorter for more umph like say a 4.10:1?