2 questions, 88 4runner
 

where do you look on the truck, to find it's gear ratio? I allways thought that a higher number meant worse low end pull, but better gas mileage. Also look at this pic, 4th one down;
https://www.yotatech.com/forums/f116...r-pics-119726/
see how his front bumper has wrap around plastic part on the end, the black piece? is this replaceable, and easy to pop on or off? mine is missing...

the gear code (axle code) will be inside the drivers door. it is a "g" followed by 3 #'s. mine for example is g292. search your gear code when u find it

The black plastic piece is very easy to replace, and can be gotten quite cheap from the dealer. Two 12mm nuts hold it to the bumper, and one 10mm bolt holds it to the fender.

52102-89106 pass side about $50 ea shop around online
52103-89106 driver side
52127-89101 plug to cover the 10mm nut $2-3 ea
91666-40618 nut 1 per side $1-2 ea
90179-08096 nut 2 per side $1-2 ea

Good luck

This may help

http://www.4crawler.com/4x4/4R_TechI...oDetermination

And yes it is easy as a few bolts on the bumper end and fleabay has them cheap

To first dude; so what does g292 mean? two other two dudes;
WOW! thanks a lot, that has been most helpful, again, kudos.

How to decipher your axle code
http://www.toysport.com/Technical%20...ifications.htm
great general info about Toyota diffs
http://home.4x4wire.com/erik/diffs/#ratios

g292 is an example of an axle code which you would have known had you looked for it.

g292= 4.10 gear ratio in a 4cyl, non-turbo differential.


The only options for an '88 4runner from the factory would be 4.10 (manual tranny) and 4.30 (auto)

Ouch! Look at that mark, right there on my arm- from the stinging sarcasm.
I looked under the hood, and on the little label inside the door, but didn't see anything like g292; Maybe I missed it, or was not looking at it in the right spot, I'll go check again.
So it probably has a 4:10. My tires are 235/75/15, is this a good setup for gas mileage? Can you think of a better setup? Again, and I assure you I do not know when it comes to this- I allways thought taller tires, and a larger / higher number ration meant better mileage , like 4:56 or 4:88, or something to that effect. I do not plan on mudding , wheeling , or rock crawling, maybe the occasional super rain downfall , or muddy trail area, around Houston.
most of my driving will be on the monster freeways here...

g292 is 4.10s on v6s as well

I have an auto and didn't get the 4.30's on my V6.

The gear ratio is the ratio of the number of turns of the driving gear to the driven gear, or in our case the pinion gear, which is connected to the drive shaft, and the ring gear, which is connected via the differential to the wheels.
4.10 basically means the driveshaft will make 4.1 turns for each revolution the wheels make.
4.88 means 4.88 turns of the driveshaft for each revolution of the wheels. Considering that, the higher the ratio, the easier it is for the engine to turn the wheels. However, this is complicated when oversized tires are installed since larger tires will roll farther on one revolution than a smaller tire, and is evidenced by a general loss in mileage when larger tires are installed unless the differential(s) are regeared.

If the ratio thing throws you off, you can also think in terms of levers: a 4.1" lever gives you a certain amount of advantage, a 4.88" lever gives you a bit more, and a 5.26" lever gives you yet more advantage. Just like a longer breaker bar lets you apply more force on a nut or bolt, higher ratio gears let the engine exert more torque on the wheels.

This is wrong

If it was a V6, the axle code would be G294

G=8"
29=4.10
4=4 Pinion (in V6 trucks only)

You might want to check your ratio, via the info plate. I have never EVER seen a 4.10 V6 Auto. Ever.

So then, for our purposes; a 4.1 running regular factory size tires would be a good thing for gas mileage purposes; since the drive shaft is making less revolutions, per 1 revolution of the wheels, that means the engine itself, should also be turning over less, theoretically, to turn over the driveshaft, a lesser amount of times.
So then, If I increased the height of my tires, say 2 inches, I should get even better gas mileage, but with less low end pull ability, plus the odometer would show less mileage, because the tires would be taking longer to make 1 full revolution; however in reality, the mileage on the taller tires, with a 4.1 ratio, theoretically again, should be better than the factory size tires, correct?

No, that is incorrect.

Since it takes MORE effort to move a larger tire, it negates the lower RPM the engine will be spinning. Hence why everyone who puts larger tires on complains about worse gas mileage.

Hmm, that does make sense. However, if the factory tires are 225/75/15, which is about med height and skinny, and you go to a 265/70/15, you only gain about 1.5 inches in height, but you lose a tad on the %. So I would then think, the weight of these tires would be about the same , comparatively speaking.
So is it the weight of the tires, that the engine rpm's have to overcome, or are you saying that height as well, must be overcome by the engine rpm's?
I would also think a taller tire, would be easier to pull/push, since it has a longer, and more obtuse curve angle to overcome; kinda like pushing a , well, a big tire, up either a inclined driveway , ( nice and easy incline) or up a set of steps, with a piece of plywood laid over them. ( a sharp incline)
I am saying that the smaller diameter tire, has a sharper curve angle to overcome for the engine, and am equating them with the sharper incline.
With the weight of the 2 diff size tires being very close to being the same.

225/25.4 = 8.858 x .75 = 6.64 a diff of 1.6 inches in width.
265/25.4 = 10.433 x .70 = 7.30 a diff of .66 inches in height.

I have not weighed the tires, but I am guessing a tire only this much bigger, probably weighs 5 lbs or less , in difference, than the smaller tire, which would only be 20 lbs of weight, or less, more for the engine to move, but at the same time, overcome a curvature of the tires, with a lesser angle to them.

If I am wrong, please, I can take it; I am just trying to use a little linear thinking here. I could see if the tires were bigger, with a much wider tread, and say m/t's or mudders, and then couple that with a larger diameter wheel, by 2 or 3 inches; because the tread will be much thicker and heavier, than on a all terrain or radial, and the diameter diff will become much more so, with the bigger wheel, and then you will be adding a lot more weight.
Then of course, multiply that by 4 tires...

Do we have any tire experts at Yotatech, or does someone have access to a tire designer/engineer that we can ask?

...Nevermind; I just submitted the question to BF Goodrich. When they answer back, I will copy the answer, and put it here, so we can all see just what
they have to say. I hope it's not just some dude , trying to answer basic email questions!