can you install 8.5" 10 bolt ring gear on a 7.5 inch 10 bolt carrier? Need Help FAST

[bjrjr16]

Hi guys, I was wondering if it was possible to install a 8.5 inch ring gear on a 7.5 inch posi carrier? Ive got a 8.5 inch rear end with gears but a junk carrier, and I have a posi 7.5 carrier, both 10 both and both are 3.73. this is for a blazer, 8.5 rear end came out of a zr2. Any help is greatly appreciated, ive done alot of research and found no one asking that question. Thanks, Brian

[droopy89]

long story short, no

[bjrjr16]

Allright thanks, Well do you know what year and dash code i need to get a 8.5" posi carrier? I know for my blazer i need like a 3.73 which would be code gt4, and a posi carrier would be something like code g85? or g50? Thanks, Brian, I want a posi carrier for a 8.5 inch gear in the blazer

[droopy89]

the posi code is g80, but the year, im not completely sure, but i think its 94 and up, as long as its a 28 spline axle it will work

[Mikz86TA]

X2. Posi will be G80 code on any year. Only difference is...If the option was for a certain year like my 2003, its a Gov-Loc unit. If it were on an older F-body, the code would indicate a LimitedSlip. 2nd gens I think are all Gov-Loc with G80 code. So you have a set of 3.73 OEM GM gears for a 8.5??? RU selling them?

[bjrjr16]

Make me a offer on the gears. The front diff I have too but that is going in my truck today, But i have another front end too(3.73), it is out of a reg blazer, the one im installing is out of a zr2 and has a bigger ring on it so it will be better for what i need it for, hence the reason why i wanted to get the 8.5 to work for the rear. I am installing all of the zr2 option parts on my 96 4dr to make it a zr2, kinda one of a kind i guess, they never came factory as a 4dr zr2, mine has a sunroof and leather aswell, its a nice ride! I also have a 4.10 rear, 3.73 posi, and a 3.42. all for sale except the posi for now. So if your interested let me know. the 3.42 has 105k, 4.10 is at 120k my 3.73 posi is at 120k and the 3.73 non posi(8.5) is 130k. Thanks alot, Brian

[Mikz86TA]

Which gears are 8.5 diff?? All or just the 3.73s? Pics and part numbers? Id like to see that 1st..then well talk$ =) THX

[Hammer Head]

X3, 7.5 won't work w/ 8.5 & visa-versa. Yep, G80 is the code. Also, to correct Drew a little, 28 splines came in around '89-up.
Do you have the pinion for the 7.5/7.625 gear set? Do you have a pic/pix of the carrier & gear set? How many miles are on these? Feel free to PM me w/ the info, Brian.

[962dr]

full size trucks and 70s camaros would have the 8.5 carrier.

[Hammer Head]

I have an 8.5 open rear carrier & 3.08 gear set.

[bjrjr16]

Yes i will get you pictures of it, should have them late tommorow, i need to get my camera back then we will be all set. I have the pinion gear to a 7.5 inch 3.73, but im planning on using it with its ring set along with my 7.5 posi carrier, unless i can get a posi carrier tommorow for a 8.5, if i do find a posi carrier for the 8.5 then i will use the 3.73 8.5 ring and pinion with that carrier and use the 8.5 zr2 rear end. Otherwise i will use my 7.5 rear with the posi carrier and 3.73 gears. so its a toss for right now. Also If you need a pinion for a 3.73 7.5 i can get one for you no problem, I just need to know how much we are talking. Also i can get alot of rear ends I just need to know price willing to pay. I dont like to go out and bust my ass and get rear end oil all over my blazer for a couple extra bucks, But im always willing to help out. I can ship the gears or carrier or both. Thanks, Brian Also does anyone know the difference between a gear box for a 95 pickup zr2 and a 95 pickup non zr2. I would like to put in a gear box since mine is loose and with the front diff being out of it it will make it 100% easier to replace.

[Mikz86TA]

By gearbox you mean the tranny or transfer case? Tranny auto or manual?

[Hammer Head]

I don't fully understand what you're tryin to accomplish here.. you plan on keeping the 7.5 unless you find an 8.5 posi carrier.. do you only have a ZR2 rear or do you have 2 different rears (one being a 7.5/7.625)? I ask this because if you only have the 8.5 ZR2 rear the 7.5/7.625 carrier & gear set will not interchange.

[Mikz86TA]

Seems like he has a stock 7.5, wants a posi. If he finds a 8.5 diff with a posi, he is going to put that in. If he finds a 7.5 diff with a posi, hes going to transplant the posi icarrier into his existing diff. But he already has a few gears lying around for both.

[bjrjr16]

This is what i have right now for gears/rear ends. these are 7.5": 4.10, 3.73 mounted with posi carrier, 3.42, 8.5": 3.73 non posi. Right now in my truck is the 7.5 " 3.73 posi, I love the posi but i know or have heard that the 7.5" is not too strong, so what i wanted to do since I allready have a 8.5 inch much stronger(so ive heard) rear end was to install the 8.5 in my truck with a 8.5" posi carrier IF I find one. I am not going to take apart the rear end to install the axle unless I find a 8.5 posi carrier. By gear box I was talking about the steering box. Mine is loose and I allready tightened it but it still wanders down the road, yes it is the gear box, no other things are loose. Reason why I ask about the zr2 gearbox is that when I went on advanceauto or napa which ever one i dont remember, they showed for the 95 pickup gearbox there is one for a zr2 and one for regular pickup. But yet they do not show one for a zr2, that is why I am confused. Okay so do you guys get what im trying to accomplish with the rear ends? installing 8.5" rear only if i find posi carrier, and keeping my 7.5 rear installed if I do not find a carrier. Thanks, Brian

[Mikz86TA]

The 7.5 had a bad rep for no reason. I have over 400HP/TQ in the TransAm and still have the 1986 orig 7.5 in it. Years back when it was still a 305 I pulled the stock 2.73s/open and replaced it with a set of 3.42s and Auburn. I replaced the carrier bearings and races, pinion bearings and races, crush sleeve, and the seals. I have had no problems other than the aftermarket el-cheapo gear whine. Still has the stock axle bearings and seals. There should be no issues with one benind a 2.2 or 4.3 unless the entire truck/driveline has been abused. Back in the day I would do burnouts, track days, and daily driving. Over 150K miles. But I am always more confident in whats 'known' stronger. So if you do find a 8.5 that will fit and its in good shape, then get it. But rebuilding the 7.5 it will be no issue behind the 4.3....or most V8s for that matter. Use quality Timken bearings (CarQuest used to have them in their brand boxes)

[Hammer Head]

7.5/7.625 can be made just as strong if not stronger than an 8.5. Use a rear girdle from T/A performance.. summit has their own brand & I picked up one from trick flow.. there's more co's out there that sell them. Are you sellin the 4.10 gear set?

[Mikz86TA]

Im looking for a GM ,3.42 ,8.5 gearset with no gouges or wear.

[bjrjr16]

Yes the 4.10 gear set will be for sale. Let me know what you are willing to pay, my zip is 13309 and i dont know the weight. Im just going to go with the 3.73 posi with the 7.5 for now, then when I find a posi carrier for the 8.5 i will just switch them out. I will look for a 3.42 8.5 gear set and let you know what I find, Is it out of a 2500 or a 1500 truck or something? Is it a semi floater or the blazer type rear? thanks, Brian

[Mikz86TA]

Mine is a 2003 S10 2wd 4.3 5sp with the 8.5 center diff. IDK exactly if there are differences in the gears from th different vehicles. Only thing would be a ABS reluctor ring rear...which mine isnt. Maybe someone will ping in

[Hammer Head]

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