3rd member ?'s

[1tonfish]

I know you guys are mudders & crawlers but theres a lot of toy knowledge on this site so here it goes. i have a 86 1ton (yeah right) 4x2 with an 8" RE, 4:30 gears (G282 on the ID plate). it has relitively small tires and winds close to 5 grand @ 75mph. I removed a 3:07 (G662) RE from an 87 which according to the id plate would be an 8" it is a 3:07 but when i measured the ring gear diameter it seems to be a 7.5". will this bolt in, are the axle splines the same? i drive about 95 miles a day on the FW. i need some mpg & some piece and quiet. thanks

ps this is my first toyo, I plan on getting a 4x4 to join the fun.

 

[2ndGenToyotaFan]

I do not think the 7.5 will go into an 8 inch housing without a lot of work....

Here's some great info for you.

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

And if you had a 4x4 I'd trade gears with you..... My 33's could use some help.....

 

[maximusRMP]

Which side of the ring gear are you measuring?
I've got a gearset here that is out of an 8" diff, measures 7.5" across the carrier mounting surface and 8" across the face of the gear.
I don't know the Toy dually too well but I can't imagine they went to the smaller ring and pinion for that type of application.

 

[2ndGenToyotaFan]

Oh, I miss read your post, I thought you had a 7.5 inch 3rd out of something else..... for some reason. So you have a 3rd member out of an 87 2wd, and want to put it in you 86 2wd? That should be no problem.

 

[1tonfish]

more info

the gear side of the ring gear is 7.5 "(no where close to 8") and the bolt side is 7"ish. i guess im asking if the bolt pattern is the same (both have 10 bolts to the housing) and are the axle splines the same??? they both measure 9" from housing surface to drive line so if it'll bolt in i'm golden. all the diff sites deal with 8" 2 or 4 pinion (for 4 bangers). this isn't a dually tho. thanks guys, makes me almost sorry for spanking all the toyos back in the day, I had a turbo subaru brat. I did go thru 4 motors tho!

 

[-DRM-]

I hope I am reading you right - but if you have a 1 ton 2wd, it's a dually, right? That used an 8" 3rd member, whereas other 1/2 ton 2wd trucks used a 7.5" 3rd member... no - they do not interchange.

I think to get that high of a gear for an 8" 3rd, you will need to pull gears out from under a Supra or other Toyota car that ran an 8" diff.

Another option would be to source a 3.90 geared 8" 3rd member from an 80 model 4wd truck (I think I got that year right - I'll check one of my aprts trucks when I get home tonight), and maybe step up in tire size on the rear of your truck to get your rpm's down for the highway.

good luck.

 

[1tonfish]

ah well

This is a 1 ton but it's not a dually. The 3rd memb is as all the diff sites describe an 8" 2 pinion (3 fins). but as i'm finding out the 1 tons have a lot of one off suspension stuff. the U joints are huge!! the rear end is a locker (doesn't i.d. as such tho) which i was gonna thro in a 4wd later. tires are a good idea, thanks. toyo i.d. plate are totally unreliable tho.

 

[WristPin]

heres what i would do.

buy either your 4X4 or just the puny axle.
swap out the axle on either the new 4X4, or from the weeney replacment one you just got.

the spring perches have got to be the same.

as an avid four wheeler, i want the axle you are running now.

all i would have to do is relocate the perches from spring under to SOA.