can anyone tell me whats all involved in doing this and setting the gears up. I found a 3.08 setup to replace my 3.73's. where do I buy one of these crush bearing for the pinion gear.

any advice is appreciated this is being done this saturday

 

i finally found this walk through, it's okay and should get you by. and i would just get a rebuild kit from summit it has everything you will need.

http://www.chevyhiperformance.com/te...all/index.html

 

thanks ..... Does like pepboys etc usually stock the shim kits and bearing required?

 

Another question. I am using a complete differential out of another 10 bolt. If I use it's current shims and install it in my rear should it be pretty close to being set right? .... I would order summit stuff however I am doing this on saturday so don't have the time to order this stuff unfortunately. This 3.08 rear made no unusual noises but I do plan on replacing the axle bearings and carrier bearings for sure.

And for a important question .... at 65 my T-5 with 3.73's is turning about 2100rpm what kind of an rpm drop will I see going to 3.08's?

 

lol my 305 was crankin out at 3500-3800 on the highway at 70 with 3.08's. but i also only had a 4 speed so yea.

 

Yeah, I remember this 82 when it had 3.23's and the 3 speed automatic it's was craking some RPM too. Now at 3.25 a gallon freeway gears are needed badly.

 

most stores should stock all the parts you need, you will need 2 carrier bearings, both pinion bearings, a crush sleave or collar which ever term u prefer, a new pinion seal, a cover gasket or rtv, a few quarts of gear lube and a bottle of limited slip additive if its a posi, a shim assortment(carrier and pinion), something to measure backlash with such as a dial indicator, something to measure pinion depth with such a pinion depth finder, something to remove and press the bearings on with such as a hydrolic press, a good torque wrench, and a brass punch for installing and removing the pinion bearing races and thats all I can think of off the top of my head...

 

as far as reusing his shims, maybe, normally the shim on the pinion gear your removing will be the right one to give you the pinion depth you're looking for, if not check depth and replace with an appropriate shim, as far as the carrier shims typically you start with the same thickness as the factory shims you had, install, measure backlash, and make adjustments from there.

 

you can use the old shims to get you in the ball park, in fact i suggest it. but i have never seen anywhere that sells the crush sleeve rather than a speed shop like summit. honestly i would say just hold off and get the kit. it has everything you need.

Trust me i have done this and just waiting until you have everything is the best and only option.

IMO use this kit:
http://store.summitracing.com/partde...5&autoview=sku


and install it as shown in the link. This has everything including the marking compound, crush sleeve, all the new bearings.... i mean it's much better to do it once then to have it up on jack stands for a week waiting for a part or shim.

just trying to save you some grief like i had to go through.

 

i got a 88 camaro with a t-5 and 3.08 rear...it turns about 1750 at 70 in fifth, so if ur lookin for a highway gear, that should be plenty

 

Where I live, there's a local driveline shop that sells crush sleeves separate, but I have to agree that you'd be better off just buying the whole installation kit since you want to replace all the bearings. You might be getting in over your head if you don't have any experience setting up a rearend though. You don't really need a pinion depth gauge. Most 7.5" 10 bolts use about a .030" pinion shim to establish the proper depth, so if you use the original pinion shim that's on the 3.08 pinion gear, you'll probably be fine there. The tools you'll need for sure are a dial indicator w/magnetic base to check the backlash, an inch lb. torque wrench to establish the proper pinion bearing preload, and a really strong impact wrench to collapse the crush sleeve, along with something to hold the yoke still while doing so. If you use a solid spacer (recommended by most here) instead of a crush sleeve, then the big impact wrench won't be necessary. 3.08's are quite a drop from the 3.73's. Only the grocery-getter T5 cars got them. Personally, I wouldn't run anything higher than 3.23 behind a T5. You're gonna sacrifice a lot of takeoff power with 3.08's.

 

I was doing some reading and searching on here and came across this ....

https://www.thirdgen.org/ls1reardisc

maybe thats a option for me as well is just adapting a drum rearend to accept my disc brakes ..... would this be a quiker and easier way to get higher gears without swapping gears? Or is there more involved then what he illustrates.

 

Well, I picked up everything today the rearend is from a 1991 camaro RS that had a 305TBI and a 5 speed. Pinion count is 13 teeth and ring gears count is 40 teeth ... That works out to 3.08 if I did it right. .... great thing is this car had a brand new torque arm mount so grabbed that and the drum brake valve so if I decide to just go back to drum brakes.

 

In all honesty, if you can keep the 3.08 rear all together and just modify the flanges on the end to bolt up your disc brakes, that's probably gonna be the easiest way to do it. Modding the flanges doesn't look too difficult at all. Besides, even if you did mess it up, what are you out, other than a dime a dozen drum brake housing? Not having to disturb the setup would easily be worth trying to mod the flanges IMHO. In fact, if neither of them are posi, then there's zero point in disturbing one. Another plus to the 91 rear is the 28 spline axles. There somewhat stronger than the 89-down, 26 spline axles. Just my .

 

if you modify the flange do the stock axle shafts work without and mods?
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drum brakes and a open rear really don't bother me since this car is never raced it's just my fun commuter car.

 

Is this the car thats gonna get the 4.3 in it?If so I really dont see it saveing you enough gas to even bother with the swap.I drive a 4.3 every day and it gets crap for mileage and I keep it in good tune.Granted it is in a truck with an aod trans but I just saw a guy named uncle tom on here getting 27/29 mpg on the interstate with l03 tbi,3.08,t-5.just my

 

well we will see if the 3.08's get me up to where I want my mpg to be and go from there. I know the 3.73 are seriously hurting my economy but even with them I hold at 20mpg average

 

No offense,I just hate to see an F body with a v-6 in it,even a 4.3.If I were closer I`d take that 3.73 rear off your hands.I`m getting bout 22 mpg on the interstate or so outa mine with a not so good prom tune(rich) and 2.73.Could be better but its better than my 4.3 powered truck.It gets about 15 mpgs.k 1500 4x4.I daily drive the truck.I`m thinking about putting the 305 outa my iroc in to give it more power.couldnt hurt the gas mileage I dont think.good luck.oh yeah it might help if i did under 80 when I get on the highway,nut I cant help myself.

 

373's are overkill ... the car actually accelerates best doing 1st-3rd-4th ... everyday driving I just go 1st-3rd-5th and it accelerates nice like that

 

I see you're running a 350 with Tbi on it, is it a totally stock 305 system? If you with those gears and if you're easily on the loud pedal you should be able to get some decent fuel mileage if everything is in good tune.. I noticed in your sig that you have a "L98" with LO3 induction, personally I believe an L98 with out the tuned port on it is just a 350, I'd just call it a TBI 350 myself, the only other really difference would be cam profile, and even if it is a stock L98 longblock its really not an aggressive cam..

 

I take it that you are going for best possible fuel mileage and not performance, the things that I think would help you best is obviously a fresh tune up, new filters all around, new fluids, synthic if possible due to less power loss, and a good free flowing exhaust. Also make sure you are running the proper amount of air in your tires etc. let us know how you make out!

 

The motor is basically this ..... 1990 corvette shortblock with 1989 083 350 TPI heads. complete LO-3 induction system (for visual smog reasons) ...Then I have early 350 TPI large complete exhaust.
I went with TBI also to maintain sorta the stock underhood looks and to maintain my cowl induction as well. However I upgraded everything under the hood to 1990 stuff for a cleaner look and to eliminate the smog cluttered LG-4 look.

here is a picture, yes I know it could benefit from a nice detailing

 

2100 RPM / 3.73 * 3.08 = 1734 RPM
(Remember your speedo will be off..)

 

thanks fullsizewagon

 

well I got the 308 rearend in for the most part now for the questions

what gear oil do I use in it? it's a 1991 camaro unit

I forgot how the parking brake cables are routed can anyone post a picture for me? drum brakes

what gears will it take to correct my speedometer. this rear came from a 5 speed camaro so I now they are available at GM.

 

and yes the car is tuned up .... it could use 350 electronics and a prom burned but seems to run pretty strong just the way it is and passes emmision tests with ease. major problem is I am a leadfoot LOL and I run the car sometimes up to 80 and thats when it starts sucking gas. So I figure if the 91 camaro with the LO-3 and 5 speed this rear came from did ok them my 350 should do just fine with 3.08's. ..... I am however at a later time upgrade the rear brakes to 4th gen setup if they wont cause a problem with my 15 inch rims. And as other have stated it's a little stronger then my 26 spline rear. ..... I will let you all know if it upped my economy.

My speedometer is off anyways reads about 7mph slower then your actually going. not sure why it's doing this because the odometer is right on because I took my 97 camaro to work and then the t/a and they both came up with the same miles. Maybe it's just the vss buffer causing this. (car has 90 electronic cluster as well)

 

end results

mapquested miles 16.1 (very accurate I do this trip alot) my cars odometer recorded 11.9 miles

1st gear starts feel like 2nd gear starts with 3.73's

no one is passing me on the freeway when I am going 55 LOL

not a dog like I anticipated either. Slow out of the hole yes but when it picks up some rpm it's a nice smooth flow of power through the gears and it pulls pretty dam good

motor sounds great now at freeway speeds no rapped up and turning high rpms at 70 lol .... at what I believe to be about 70 it's turning about a little over about 1700rpm
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sorry I don't see any real feasible way to give you a MPG difference but on this 32 mile round trip to get my son it didnt use as much gas from what I saw by fuel gauge movement.

 

well fuel mileage seems to have went up. cruising with the flow of traffic keeps it right around 1700rpm so I'm quite happy with the swap .... Not sure how a 305 TBI does with 3.08's but my 350 does just fine with them just have to shift it a little more then I used to. When I do my clutch I will change speedo gears and let you know it's true MPG. I am also planning on having someone burn a custom chip for it, 350 injectors, 350 electronics. If I can find someone to datalog the car.

I think after doing the ECM tuning there will be no need for a V-6 swap now

 

the car is averaging 23.4mpg now

 

any everyone thinks these cars are gas hogs... nice!

 

23.4 isn't a gas hog .... thats an average combined driving at each fillup is all it could be getting more and it could be getting less depending what I'm doing.

 

lol my car will do good to get 10 or 12.....dang carburator.....and the 4.10s....and the non od trans......rofl

 

right.. that was my point..