Dope

So this past weekend I spent a day disassembling my rear. Don't believe anyone when they say you NEED a lift, or multiple people, or anything of the sort. This was my FIRST time under the corvette (just got it a month ago) and it was all very straightforward and easy. The only part I got hung up on was the halfshafts. I didn't realize you had to just yank it out of the diff. I spent literally an hour trying to figure out how to get the boots off (I figured there was bolts or something under there). It also took me an hour to get the car in the air (it's a lowered FRC). Ended up backing up onto some boards, then lifting the front one side at a time and setting it on ramps. Then I put the jack under the rear and lifted it high and put jackstands on the frame. Like this:



I used this guide EXCLUSIVELY for the install: http://home.hvc.rr.com/joesvette/98vette/98rear.htm

The Mike Mercury and Corvettefever write ups seemed to have wayyy too many steps (maybe cuz they were for autos?)

Just a note, in that guide, it shows the ABS block that has to be moved around and such. There is no such block on my 99 FRC. Not sure what other models don't have it. It was just 2 brake lines in the general area which I just wired out of the way so they wouldn't snag on the carrier as I took it off. Here's a pic:




Once you lower the rear (not done yet in this pic) and wire the lines to either side (I stuck em to the exhaust), they aren't even the slightest pain.

Also, you only have to remove the midpipe. I left the mufflers and over-axle pipes in. I just stuck some more wire through the bolt holes and hung them from a nearby bolt so they would be out of the way. Totally useless to remove the mufflers, they aren't even close to being a problem.


Definitely get the harbor freight tranny jack (I recommend 2 unless you have a friend, the rear diff weighs ~75lbs and isn't fun to position in place with limited clearance as you lay on the ground). You can see my rear subframe sitting on it in this pic. You can see the new DTE rear sitting on the ground as well. Wire the brake calipers to the upper a-arm to get them out of the way and to prevent from damaging the brake lines.

Only stuff you have to remove before you drop the rear, is to pull 2-3 tabs off of a single wiring harness that is attached to the rear subframe. The brake lines were not attached if I remember. There is also a single weatherpack connector on the TOP of the diff.

The rear only needs to be dropped like 2 inches to get the diff off. I don't even think I really needed to drop the midpipe and the torque tube cover. The engine didn't come ANYWHERE near hitting the firewall, nor did the metal bracket on the fuel rail (Driver's side). I'll check clearances on the torque tube cover tomorrow if I think of it. I almost got the diff off without even lowering the tube at all!


Random diff comparison pic

I actually still haven't buttoned it up, waiting on a solid transmission mount from Vettebrakes (coming tomorrow morning).

All in all, I did maybe 6 hours of actual work. A lot of stupid mistakes (like figuring out I had to jack up the lower a-arm in order to seperate the upper ball joint and upper a-arm), the halfshaft boots, getting the car in the air, etc. Plus, being super careful and slow because this was my first time under my vette. I am far from a good mechanic too, trust me.

So, to anyone who wants to pay someone $500+ to do the install, forget it! Spend the 500 on some mods :)

Dope

Mike Mercury

you got it up high, and that really helps. Since some of us did it the "hard way" early on (which is called for in the Chevrolet shop manual)... an easier way was determined and you were able to take the easier route because of this.

I now know (as I mentioned on my web page as an addendum) it is not necessary to unbolt the torque tube from the engine. I'm glad you used the "modified" method. Maybe now others will be more eager to do this themselves.

Dope... don't you feel a lot better knowing that you reassembled the read-end components, and not some mechanic-wannabe at a Chevy dealer?

:cheers:

Dope

Mike, I didn't want to make it seem like your write-up was crap. The truth is, it was getting confusing skipping between guides (I had printed them out) so I just used the one. I did read through yours and did pick up a few tips (notice the wheels under the car! ;) ). I was glad to find that it wasn't nearly as complicated as any of the 3 guides made it out to be. Luckily since it's an M6, there's no seals or anything special (wiring) either.

I always do my work, it is very rewarding. The only things I haven't done are welding, and when I first got my OLD camaro (3 years ago), I had a mechanic swap out my torque converter for me. Quite frankly it was too big a job for me back then, I had just done my FIRST OIL CHANGE EVER literally months before. Plus I didn't have the array of tools I have now (my toolbox weighs at least 100-125lbs).

I figure, with all the money I save on every mod, I'm paying for future mods. The cycle never ends! Plus, like I and you said, there is just no beating the sense of self satisfaction you get from doing the install. I never could understand the guys who just write checks to get mods. Seems...wrong in some way. Though I suppose if money were no object I'd probably write checks too, and spend my time on real projects like building a kit car or something (FFR Cobra with LS1/T56? What?)

As a side note, I wish I could have done my own write-up, but I was way too busy trying to get it done to be taking pics of every step, etc. I had originally planned on a Sat/Sun install, but I got rained out Saturday.

Dope

ALLKAR

Dope-
Excellent post,:thumbs: I'm wanting a 4:10 swap.

Looks like this will be my next project!!

dads01dream

Hey Dope CONGRATS!!! I'm totally with you & Mike when it comes to working on your own car. Unfortunately, I have an A4 and from the looks of what you've written, the diff swap is far more involved with the A4. :(

You got the diff from DTE, how much did it cost you? Did you buy a complete diff assembly or simply send yours down for the gear changeover?

Thanks for doing this writeup and giving the rest of us a little shot of encouragment.

:seeya

brrymnvette

It is ALOT easier than people think. I put my 4:10's in fri. Took about 3 hours. HAd a little problem with an axle seal though. Just fixed that last nigh in about an hour.

IMQUIK

So when ya gonna come up to Kennesaw & help me put in my 3.73's? :lol:

kumar75150

Thats dope man. :jester

Dope

Just a few more pics:



New diff installed with poly tranny mount (VBP).


I love surprises. What's this? Oh, it's just a wiring harness melted onto the exhaust! (I had already pulled it off, it was literally melted into the shape of the exhaust).


Ugly. Looks like whoever did the Corsa install for the previous owner was a maroon and decided to lay the wiring harness right on the exhaust (I believe it actually runs UNDER the exhaust stock) I got lucky, it was NEARLY burned through all of the insulation. Just looks like a mangled mess now, but no bare wires (or shorts). Whew.



Wrapped it up in duct tape to keep it dry, and then wrapped it in heat reflective tape (from Summit). Also routed it correctly under the exhaust, as you can see.

I also found a missing bolt on the torque tube cover, and a missing bolt on one of the header tabs. Also, the O2 sensor wires were partially melted from resting on the exhaust. This is why you DO YOUR OWN MODS!

Note: you do have to remove the torque tube cover. It is VERY close to the torque tube, so any lowering of the tube itself requires removal of the cover. Thank god for impact wrenches!

No WOT yet, but feels pretty nice around town. Makes the cam and nasty clutch a little more livable.

One final note, don't torque the brake caliper bolts too much. I snapped one with minimal effort. Luckily there was enough sticking out that I could remove it and get a replacement.

Dope


[Modified by Dope, 12:39 AM 10/9/2003]

George8211

Good Job... :thumbs:

aaaaa

Hey, thanks! It looks alot easier than I thought. :yesnod:

Karl_in_Chicago

Nice job and thanks for taking the time to take the pics. Good grief, what kind of a moron laid a wiring harness on top of the exhaust? :eek: And to find missing bolts, too? Like you say, whenever you can do the work yourself that's the best. Better to spend the money on tools once then to continue to pay somebody else to do things you can do yourself.

Mike Mercury

ABSOLUTELY !!! :yesnod:

a6fan

Looks like I just found another project for the down-time this winter!
On an M6 car is it worth going 3.90s ove rthe 3.42? I drive mainly freeway and love the 25.5 mpg but would like a "little" more out the hole.
:flag

Dope

3.90s are not a problem at all. 75mph on the highway is 1900rpm. It makes 6th a lot more usable, as I now use it in slower speed zones (50mph and up basically).

I'd go with 4.10s unless you have a reason not to. I almost did, but it would ruin my 1/4 mile experience. 122mph traps + 4.10s and 25.7" tires would be too much. Would have to shift to 5th or bounce off the rev limiter the last bit of the track.

Dope

Mike Mercury

All 6 speed C5's have the 3.42 from the factory. Many upgrade to the 3.73 since it's still useable with run-flat tires. 3.90 and 4.10 ratios usually require upgrades non-run flat tires due to serious loss of traction. ;)


[Modified by Mike Mercury, 4:18 PM 10/9/2003]

dads01dream

Some scary pix here, good thing you did this mod before something SERIOUSLY went wrong under there. :auto:

Patches

Excellent writeup and entertaining to boot. Kudos to you for taking this on yourself. It's cool when someone goes against convention here because they haven't been influenced by previous experience under the car or takes everyone here at their word.

Congrats and great job! Enjoy! :cheers: :thumbs: :steering:

jmzvet

I got over 25 mpg on a 300 mile trip ( cruise set on 80 ) so don't let the gas mileage scare you away :cheers: .

lotzahp

wow - I'm inspired to try this myself. But it still looks kinda scary.

I have a 98, and like HCVONE's website shows, I will have to frick with the ABS modulator located at the rear. :(