i have a 2wd with a 7.5 inch rear axel and i think i may have found one of the 8 inch differentials and would like to know a sure fire way to identify it by the differential itsself. i dont have a vin # and any way to find out what it was but im wondering if i pull the axel shafts could i count the # of splines on the axel shaft to determine whether or not its 8" or 7.5" being the 7.5 inch has 27 and the 8 has 30. if anybody knows an easier way, let me know aside from the vin # thing and completely tearing the chunk out.

 

http://home.4x4wire.com/erik/diffs/

 

i'm 99% sure that the 7.5's have 5 wheel studs and all the toyota 8's have 6.

 

TC,

As I read the link above. It only added to my confusion.

When I look at types of diff's
I looked at 85-95 4cyl.
I looked at the front.
it says 86-95 IFS trucks use a 7.5 diff up front.

when I look at the rear.
for the same year.
it says..
All pre-'95 4-cylinder 4wd mini-trucks & 4Runners use the Toyota 8" 2-pinion differential front and rear .

now am I reading this wrong?

doesnt it say all pre 95 4 cyl use the same 8" FRONT and REAR????????

I thought I had this figured out...that I had a 7.5 up front and a 8" in the rear till I read that...

Then to further add to my confusion...
Bamachem,

If I have a 7.5 up front and a 8" in rear......
wouldnt that mean I have 5 studs up front and 6 in the back????


I am starting to get dizzy.....

HELP..........

 

all 4WD fronts on all non-tundra 4WD toyota USDM trucks are 7.5" ring gears. all rears on those trucks are 8" ring gears. all of these trucks have 6 wheel studs at all 4 corners.

in the early years, the 2WD trucks had a 7.5" ring gear in the rear axle (no front axle by default). those trucks had 5 wheels studs at all 4 corners.

 

2wd trucks before '79 had the 8 with 4.10 or 4.375 gears
2wd 1 ton trucks had the 8" with 3.90, 4.10 or 4.30 gears
2wd trucks with 4 speeds had the 8"(every one i've seen at least)

 

lol oh great more confusion.........................

 

right but before i go tearing into the one i found couldnt i just pull an axel out and count the splines? as i mentioned i do not know what type of truck it was out of all i know is it was a pre 89 2wd p/u. im thinking it was an 88 with a japanese bed. i have been to that axel id site and it is nothing but confusion that i have found to be about 75% accurate. i just dont want to tear it apart completly untill im sure its the one i want to rebuild.

 

Easy. Check the gear code out. If it starts with an F it is an 7.5". If it is a G then 8". All 4 speed 2wd trucks that I came across are 8".

James

 

like i said i dont have the truck i just have the axel sittin on my garage floor.

 

actually, you haven't said that yet. if the axle is on your garage floor, then pull a shaft and count the splines. hell, just pull the 3rd and measure it.

 

what I am getting from this thread is .....remove your 3rd member and measure...there doesnt seem to be any good definitive way of identification of your diffs.

I see alot of information and opinions but nothing that will tell me definetly what I have.

I know this isnt my thread but was really hoping to read this and to be able to say I have this rear end and this front end. So far I can't.

 

i wasnt here to argue... i was just trying to figure out if anybody had any knowledge of how to determine the type of axel aside from the vin number plate. the pictures in the link above show all the 4wd types but i did not see anything about the 2wd 7.5 inch diff. at any rate mine apears to be identical to the one one the left (4 cyl diff.) but i do not know for sure. i will most likely take the axels out to see if they are the same but i really didnt want to pull the 3rd member if i dont have to. pardon my ignorance of rear axels but if im thinking correctly if i pull the axels out then all i have to do to remove the 3rd member is remove the small bolts arround the diff? do i have to remove the pinion thingie with the punched bolt? (for lack of better terminology)

 

nope, just pull the shafts and unbolt the diff. i usually whack on it with a big mallet to loosen up the gasket/rtv.

 

cool kyle, got it out now im trying to identify the gear ratio but it is definatly an 8 inch ring gear. to figure the ratio can i simply count the teeth on the ring gear and the other (pinion gear i think its called) and then i have the ratio?

 

ok i have 43 teeth on my ring gear and 14 on the drive pinion thats a 3.07 (you are supposed to calculate from the drive pinion and not the inner pinions,right?) i measured the diamater of the ring gear and on the outside it is 8 " so i think its an 8 inch gear.

 

definitely an 8". toyota didn't make a 3.07 7.5" rear end, so i think they just swapped the 8" in instead rather than develop higher gears for the 7.5. i take it you have a 4 speed truck?

 

well i dont actually , my truck is a 94 2wd 22re 5 sp that has been lifted and is getting setup for pre running. the truck i pulled it out of was a 4 speed i think i dont have the vin # available but im planning on going back to the yard and looking to see if is a g662 code which would make sense. by the way kyle i appreciate the help with pulling the chunk out. i didnt rrealize i could do it as easy as it was. my truck has a 7.5 inch rear end with a 3:42 gear on 31x10.50 tires. i think im going to go up to a 4:56 or maybe a 4:88 since i may go up to a 32 or 33 inch tire. the main reason i want the 8 inch diff is because the rear posi diff is a whole heluva lot easier to find and is also alot cheaper from wat ive seen. ill probablly go with one from downey. have any of you guys seen a quality lsd cheap?

 

I didn't mean to come across as arguing. I was just a little frustrated. There seems to be a lot of conflicting information in this thread. I was hoping to be able to identify my diffs with the info you recieved. So far I am still confused.

 

actually you can get a junkyard posi for the 7.5 in an early 80s supra, also detroit makes one.

the only posi diffs i'm aware of for the 8" are the mkiii supra(86-9?), detroit truetrac(gear type), and auburn(clutch type)