Ron U.S.M.C.

This is a breakdown of my build. Some of these parts are necessary for the build and some can be changed to match your personal preference as in brand and style L.S.D./Locker.,etc.

1. 3.42 ring and pinion =$ 200.00
2. master bearing kit = $ 90.00
3. axle bearings and seals = $ 30.00
4. 28 spline Eaton posi. Unit = $ 500.00
5. 28 spline axles = $250.00
6. installation/labor = $ 300.00
7. and if you want ,a LPW Ultimate support cover = $ 160.00
8. Thats $1,530.00 counting the cover.
9. 3 year warranty on parts and labor

Ron U.S.M.C.

Camarslow

Damn man you could've at least painted it. J/K, looks good, what do you have under the hood that requires the upgrades?

Ron U.S.M.C.

Its a 5.0 with some bolt -ons, but I wanted to switch from 2.73s to 3.42s and upgrade to a Eaton posi. The LPW cover is a necessity in my book and L.P.W. makes a fantastic product that will accommodate the tube braces if you want them .

Ron U.S.M.C.

Here's a link to Jegs were I bought the cover = http://www.jegs.com/i/L.P.W./619/301-7.5G/10002/-1

SKELITOR117

iTrader: (3)

Noice.

SKELITOR117

iTrader: (3)

How does it feel with a new rear end?

Carlos773

iTrader: (3)

Why not find out for yourself? Every V6 thirdgen in any yard will probably have 3.42s. Open but its still 3.42s. Its one of those upgrades where you wonder why you never did it sooner.

I went from a 5.0 TBI with a LT1 cam/2200 Stall/2.73s to 3.27s and it made a world of a difference even more with the 2200 stall. Now imagine going from that setup to a LT1 with a Yank SS3600...

Ron U.S.M.C.

It is a huge difference when coming off the line and it actually pushes me in to the seat much harder than before ,at least hard enough that the safety belt even locks.
You can feel the rear end grabbing with the Posi.with both wheels,kind of digging in. Much more responsive at any speed. I like gunning it from a stop/or roll from the on ramp on to the interstate and a back road I found. Nice...RPMs sound fine while cruising at 65mi. per hour, but sounds a little high at lets say 75 with the 3.42s and overdrive.

Also I can lay a long "two" wheel peal if I wanted to. I don't but the option is there. Its worth every penny I spent. Also the Corvette servo I installed into the transmission works really well, nice and firm shifts. Between the gears and servo I can bark them from 1st into 2nd and chirp them from 2nd into 3rd. and nice and loud.

Thats even with the Posi. and a ton of tools/etc. in the rear compartment.

skip91

ronusmcmma,

Great looking car...! I have thought of doing the whole rear end change and now it's time to pull the trigger. After reading your thread, I have already been to Jegs and started my shopping list. I do have a couple of questions for everyone though.

1. What are the pro's and con's of a limited slip versus a posi-trac rear end.

2. I noticed the axles and posi unit are 28 spline, but the ring and pinion gears I saw on Jegs were 27 spline. Is this an issue or normal?

3. Is there a kit I can buy that has the extra stuff I need? Such as fluid/oil, gasket, etc.

4. I'm looking at going the 3.73 route instead of the 3.42 route. I don't plan much long distance travel at all other than the rare 25 miles (90% highway) one way to and from work. Will the 3.73's and T-5 suffer too terribly much?

5. I have a '91 RS, T-5. It came stock with a 3.08. I've noticed ring and pinion gears come in either 2-Series or 3-Series. The difference being 2-Series fits 3.08 and numerically lower carrier and 3-Series fits 3.23 and numerically higher carrier. I'm assuming I should get the 2-Series?


As with everyone, money is best saved nowadays. With this in mind, I went with comparable Jegs components when building my shopping list. Here is what I have come up for my parts list thus far:

Eaton Posi-Unit, P/N 362-19599-010, $519.99 (http://www.jegs.com/i/Eaton/362/19599-010/10002/-1)
OR
Detroit Locker Limited Slip Unit, P/N 357-912A317, $389.99 (http://www.jegs.com/i/Detroit+Locker...2A317/10002/-1)

Moser C-Clip Replacement Axles, P/N 718-A102804, $250.99 (http://www.jegs.com/i/Moser/718/A102804/10002/-1)

Moser Axle Bearing & Retaining Plates, P/N 718-9563, $29.99 (http://www.jegs.com/i/Moser/718/9563/10002/-1)

Jegs 10-Bolt Ring & Pinion, P/N 555-60009, $159.99 (http://www.jegs.com/i/JEGS+Performan...60009/10002/-1)

L.P.W Rear End Support Cover, P/N 619-101-7.5G, $154.99 (http://www.jegs.com/i/L.P.W./619/101-7.5G/10002/-1)

I know everyone has lives of their own, but if someone can find the time to provide feedback, I would certainly appreciate your effort. On a side note, I have purchsed, but not installed, a set of C6 Corvette wheels, the 18" and 19" ones. I doubt it does, but will these wheels have an influence on upgrading the rear end?

skip91

sofakingdom

iTrader: (1)

If you replace the gears, get the carrier of the same series as your new gears. I.e. you're putting in 3.42 or 3.73, get a 3 series one.

"Limited slip" and "Posi Trac" are the same thing. Limited slip is the generic name for such systems; "posi" was GM's trade name for it back in the 60s, and it sort of stuck. A locker is something different though.

No those wheels won't really affect your gearing; the OD of the tires is about the same. Stock. the tires on these cars are in the 26 - 26½" range; the Vette ones aren't too much different from that.

You'll also need a "gear install kit" with all the bearings and such, I'd strongly recommend a crush sleeve eliminator instead of a crush sleeve, and some tools. Search posts on this forum by my userID and you'll find pics of the tool.

JamesC

iTrader: (5)

[QUOTE=skip91;51513891. What are the pro's and con's of a limited slip versus a posi-trac rear end.[/QUOTE]

1. Limited slip and posi are the same thing.

2. 27 splines on the pinion.

This may be helpful at some point:

https://www.thirdgen.org/forums/tran...-10-bolts.html

JamesC

skip91

Wow...! Thanks for the quick reply guys

I found a guy selling a complete rearend that has all new:
1. Richmond Gear Differential Install Kit (bearings/seals) (Jegs, P/N 836-83-1044-M)
2. wheel cylinders
3. shoes
4. Eaton Posi Unit (Jegs, P/N 362-19599-010)
5. 3.73 Richmond gears (Jegs, P/N 836-49-0007-1)

The one thing that now puzzles me is that he installed the 2-Series vice the 3-Series. Am I correct in assuming he did not change his original carrier?

I wasn't planning on buying a complete rearend, but he's only asking $350 for it. I was just going to install the parts into my original rearend.

Again, thanks for the "schoolin' " and quick replies!

skip91

Ron U.S.M.C.

Dose he have receipts for "everything" and who put it together ?

Also if hes using a 2 series carrier(the Eaton Unit) with 3.73 ring and pinion than that means he used the thick gears. Thats the only way to use that ratio in a 2 series carrier and the ring and pinion he is listing seems to be just that, a 3.73 for a 2 series carrier. 350.00 is a really great price considering the Eaton posi is over 500.00. alone.

As I mentioned,get receipts and open the differential and take a look to see whats really in there.The reason I mentioned "who put it together" is so you can talk to them about the install concerning parts used (Master Kit,etc.) Well I guess that the master kit including the axle bearing and seals is irrelevant because you will have to buy new ones .I do not beleave you can reuse the ones that have been already installed in his rear.I may be mistaken about that so maybe someone can jump in and tell us for sure.

project89

iTrader: (1)

they make gears that fit other carries.

i.e they make 2.73 gears that fir a 3 series carries
they also make 3.42's that fit a 2 seires carrier etc etc

so if he didnt change the carrier he got the gears that were made to fit it

if u try putting 3 series gears on a 2 series carrier it just wont work, so if it went together it has the right parts

sofakingdom

iTrader: (1)

No, that they don't.

Not possible to go that way. The other way (3 series gears on a 2 series carrier), yes; but not 2 series gears on a 3 series carrier.

Here... from a week or 2 ago.... tired of typing it OVER AND OVER.

https://www.thirdgen.org/forums/tran...esiioriii.html

88fastgta

iTrader: (9)

thats nice but with us modded tpi guys pushing over 330whp and 400wtq i would rather get a moser 9 inch or something... im already working on my 3rd rear end......

skip91

Found this ad locally. I'm thinking it's a really good price at $450, but not sure about the gear being a 4.10. That's probably too much isn't it? I rarely drive my Camaro, but when I do it's 90% Interstate for 50 miles round trip.

"Used, but in good shape 3 series 10 bolt rear end, with 4.10 Richmond gears, Eaton detroit locker, and Moser 28 spline axles"

Thoughts please...

Alain2

Will the diff able to handle more HP and torque with this upgrade? I always thought the 10 bolt was very weak, even when upgraded. That cover looks very nice btw.

Ron U.S.M.C.

I'm sure some of the guys here can give a precise RPM at 65 mph. with 4.10s and a manual trans.but I will say that even my car with the 3.42s is running a little high at that speed .My Tachometer is not working but I can tell when the engine is over revving and that's with overdrive.

Edit = To bad your running a manual because this could help you. = https://www.thirdgen.org/forums/tran...4-11-whos.html

3rd one for me

what is a crush sleve eliminator ?

Ron U.S.M.C.

Basically I wanted a L.S.D. with a 3.42 gear ratios from the 2.73 open differential I had.

The shop that did the install (called "The Rear End Shop" ) said to upgrade to 28 spline axles from 26 and use the 28 spline Eaton Posi. with the L.P.W. support cover and that should allow me to push the ten bolt hard with the set up I'm running now ,including anything up to a 350 upgrade pushing around 400 hp. when the time comes.

Keep in mind this is with the auto trans and street tires,that can be considered a soft launch. If your planing on pushing your car with sticky tires/slicks or even street strip tires/hard launch, than a 9in.or 12 bolt is the way to go. My car is a street car and I really have no need for either of those, although with all the praise concerning the two I had considered them.

sofakingdom

iTrader: (1)

Crush sleeve eliminator

http://www.summitracing.com/parts/RAT-4111/

3rd one for me

thanks for the info.I'm going to change the gears in mine from a 2.73 open to a 3.23 pos, and was looking for a easyer way to set pinion shaft.

devianb

What about the drive gear and driven gear in the transmission, did you change those? If not how far off is the speedometer reading?

Ron U.S.M.C.

After all the work on the car I still have not switched speedo gears. With 26.8in.tall rear tires and the 3.42 ratio ,and this is nowhere near a extremely accurate reading but the digital speed indicators that you find on the road side say I'm right on. Ive been clocked by the cops several times with the gun pointed right at me with no problems.So I'm going to say it is accurate.

3rd one for me

Haven't put it on the road yet.But I am going to check what gears are in trans and put the right ones in it.

DoWork2day

NEED HELP I have a 406 with World Sportsman 2 heads, 510 lift on a flat tappet cam, other than that stock lower end. Should be in the neighborhood of 450 horsepower?
I didn't read all the posts, looks good though.
_______ I want to sell my 9bolt in the car and upgrade to at least a 4th GEN 7 5/8 (or is it 7.5) I MAY HAVE TO BUY AN AFTERMARKET 9INCH or Moser or other racing rear end___________________________
I need to know what to do for a rear end... thought I'd start here. IF anyone knows a thread already going, I want to find out:
1. whats the likelyhood of a 10 bolt such as the modified one here, holding up to my 406 at the drag strip
2. Are there any for sale on thirdgen.org?
3. My main point is, does anyone have experience drag racing a stock housing that has been modified, is it worth my time/money......

I am looking to buy one of three ways, junkyard 10 bolt and modify it........ or... buy a modified factory housing thats already modified..... or spend over a $1000 on a used racing rear end, such as my brother bought a 9" for a Cutlass at $1,350.

DoWork2day

If there is a thread on thirdgen.org that deals specifically with my concern, can someone point me in that direction. I also wonder if thirdgen.org has a "rule" against starting a thread called "Want To Buy a rear end that will handle 500 Horsepower". Thanks in advance, Eddie.

DoWork2day

.

JamesC

iTrader: (5)

I'd suggest putting an advertisement in our site's classifieds. Also a search will probably answer most of your questions. Most members will no doubt recommend buying an after market rear end.

JamesC

3rd one for me

I have helped modifed a 12 bolt to fit a 84 Monte Carlo.That is a lot of work and angles to watch.If you don't have expearince doing this, your best bet would be going after market or buying one all ready done. And yes it would coast over 1000 to have someone else build one. A fourth gen rear would be ok for street but not sure how it would up on strip. I would go with a fourth gen rear for cost reasons and it would be easyer bolt in.

Al Hasse

I've changed the rear in my 89 a couple of times. First time I swapped out the whole axle for the disc brake set up, and in so doing, I went from a 3.08 (stock) to a 3.23, posi to posi - that swap didn't do much to the speedometer, it indicated about 5% higher than actual, so was easy to deal with the error. Next swap was everything except the housing, new 3.73 gears, Eaton carrier, new 28 spline axles, and LS1 disc brakes. With the new 3.73 ratio, new drive and driven gears were required (3.08 T5 has the wrong drive gear for this ratio), but I chose the wrong driven gear, 21 tooth instead of 20, and I'm still off by 5% on the high side. The 3.73 swap made the biggest difference in acceleration.

Ron U.S.M.C.

Just a follow up.
It’s been a few years now and the rear is holding fine.
I get on it when I want and it still barks and bites like the day I had it put in.

a62belair

Just an update to this old thread, I put a 3:45 9bolt in place of my 2:73 10bolt. 60mph used to be around 1600rpm, but now is at 2000rpm. At 60mph (GPS) my speedo is reading 75mph, At 30mph (GPS) my speedo is about 42mph. I have speedo gears from a V6 car with 3:42 10bolt, and the rear to upgrade later as above, but it has been to cold to swap yet. So I conclude there is 15 mph difference 2:73 to 3:42(3:45) and around 400 to 500 rpm difference at 60 mph.

MY87LT

iTrader: (2)

Hey Ron,

Your rear end rebuild is pretty much what I want to do to my car but with maybe 3.73 gears. Just out of curiosity, what rear brakes do you have? Drums or Discs?

Ron U.S.M.C.

Drums.
They're fine for my DD.
I have fun with the car but nothing serious.

Seems like with the new MOOG rear springs and "Gas a Just" shocks I get a little more wheel hop than I used to with the old worn out Monroes and stock springs and I don't like that much.
I will be changing from Cooper Cobras to Mickey Thompson Sportsman radial all season S/T tires as soon as these were out .

Also here's what I recently did to the front brakes. More than enough for me.
Link =
https://www.thirdgen.org/forums/brak...brake-job.html

MY87LT

iTrader: (2)

How much power is your engine putting roughly?

articwhiteZ

iTrader: (56)

you can put alot of money into the 7.5 rear..and the sec you add 400 hp and sticky tires that bite...you will kiss the ring and pinon good by! just a fact of life is all..

i smashed 4 ring gears in a year with just 11.70 runs in the 1/4 mile. order a 9" ford for it and never think about it a 2nd time..

on a side note: dont add HP. to get the car to run in the 12's or 11's and you might get it to last a few years..but why bother.

Night rider327

iTrader: (13)

100% agree. I made that very same mistake. I wasted close to $1500 on the sorry 7.625" rear end.

I added yukon axles, power trax lock rite locker, T/A alum support cover, timkin bearings, redline shock proof oil, etc etc.

The thing still broke the ring gear on one, then swapped parts over to another one and broke pinion in it.

I will say, it did last 2-3 years while I was getting my suspension/chassis/tires in order, but as soon as I started hooking, it broke. I was running 11.40's @ 118, 1.60's 60'.

I then spent out $1800-2000 and put together a Ford 9" and never looked back.

Ron U.S.M.C.

You should not be hooking hard with a 10 bolt, even with upgrades.
That is SPACIFACLY stated in this thread.

The 9" and 12 Bolt are recommended here from the "beginning" so you don't waste your money....., if you’re planning on doing that.

My 10 bolt build was done by some of if not the best rear end specialists in the business so I don't have to worry about "did they do it right".

Its application specific. Meaning it fits my purpose perfectly.

As asked above about hp with my car. I’m lucky to be pushing 200 hp using an automatic with street tires. Absolutely no reason other than bragging rights to use the 9" or 12 Bolt for me.

Its been 5 years now and I do have fun with my car even though it not on a track. I push it hard for what it is and no trouble so far.

Night rider327

iTrader: (13)

Yeah Ron, I fully agree with you. By now we all know the limits of the 10 bolt. Yours is perfect for your build and will work great for most guys on the streets.

I just wish I had been smart enough 8 years, not to waste money on the 10 bolt.

Mine was a really strange case though. I built the car as a street performance/daily driver ride.. Took it to the track and I trapped alot higher than I figured it would. Goal was a high 12 sec/low 13 sec 105-107 mph car. I ran something like 13.40's @ 110 with an open 3.42 gear.

Got some tuning in over the next few mo. and was trapping in the 113-114 mph range.

Knew i needed some type of posi, so built the 10 bolt rear with locker and what not.. More tuning, less weight, etc and trapped at 116-118, ET slowly dropped but still no traction.

Worked on suspension, tires, etc and started running 11's and broke the rear end.

It was more my poor planning and getting hooked on 'it can be faster just if' than anything else really.

Ron U.S.M.C.

Running at the track sounds really fun and some day I might try my hand at it.

It will take having another car in my life to do it though.
Its taken a lot of work to get this one to be dependable and now I enjoy using it as a DD so thats kind of out of the question until then.

I always respect the opinions and advice here.

Thanks guys........

roadthrills

The main weakness of the 7.5 is simply it's small size. A crush seal eliminator (solid spacer) is the only way to make the 7.5 live behind higher horsepower. There's just too much deflection and the pinion tries to climb up the ring gear. I know this from talking to a guy at the dragstrip running flat 7 sec 1/8 in a 406 powered Brodix headed extended cab S10. He also told me for the first 2 years he ran on stock axles. He was also running a girdle cover and had welded the exle tubes to the center section.

Ron U.S.M.C.

I'm not running much power but have the Support Cover just to help protect my investment. Lode bolts are torqued to 10 ft/lbs on to the Bearing Caps and the cover is 1in. thick with only gasket maker being used. No gasket. Metal on metal only.

I asked about the solid spacer and was told it was not necessary with the cover for "my" application. ( soft launch )
Then he explained that once the required space is achieved the nut locks every thing in place. Or something to that affect.


Just so everyone knows the difference between a 10 Bolt and 9" here's a few photos just of the ring and pinon.
I was kidding around about my car not having the power to turn the mass of the 9"
but I believe there could be some truth to it. A 9" and tall tires could kill what little I do have off the line.

Danny_VXH

Difference looks huge. I think i might just go for a setup like you have as well.

I'll have to check the the shipping costs and all that. 21% import tax always kills my buzz about ordering something nice and costly like this.

1982indy500

Ok Quick Question I'm Dropping A 385 Stroker (450+ Or So HP)In My Camaro And Its Just Going To Be A Weekend Car/StreetRod Don't Plan On Going To The Track Or Etc. But Would Like To Have Fun In It Also,Do You Think This Set Up Will Hold Up?

midias

Keep normal street tires <= 235 and it should be fine.

Ozz1967

iTrader: (4)

I'll add my comments. I have an 84 T/A, rear disk brake and factory 3.73 set up. I did exactly the same thing Ron did back in 08 when put my 355 in the car except I went with a Zexel Torsen 28 spline diff and Moser 28 spline axles. I used the same LPW cover but I went a step farther and welded the axle tubes. the only thing I was completely stupid about not doing was going with a Ratec solid bearing spacer insted of a crush sleeve.

there are a couple members here that have done what we've done but have added the Ratec bearing spacer and are running 500-700hp on these rears. It can be done. Is it smart? Eh...I probably wouldn't go that far, but 400hp eaisly.

Ron U.S.M.C.

Its the hard hook that breaks the 10 Bolt. Even the 1st to 2nd shift in my car could be considered hard because of the loud bark I'm getting.
Its a solid , fast shift at WOT that does the tire barking but the 10 Bolt is holding strong.
For those that have not seen them yet here's the new tires Mickey Thompson came out with for street cars like mine. The "Sportsman S/T" , I put them on a week or two ago.
Love them....