I have an 03 5AT Coupe ( Bose, Sun Roof, 18's ) and bought a used 3.5 diff without VLSD for cheap. I figured since I didn't have VLSD on my 3.3 then I wasn't going to miss it on my 3.5. Well, I dropped the 3.3 diff and to my surprise, I can't spin the hubs in opposite direction unless I apply a LOT of force ( unlike the 3.5 one which I can easily spin in opposite direction ). If I spin one hub on the 3.3 it'll turn the entire diff and move the propeller hub instead of just spinning the opposite side like the 3.5 does.

So my question is...I thought 03 5AT Coupe's couldn't have VLSD ( not even optional )? Other than opening the differential carrier ( It's more messy than I care for ), is there any way to tell if maybe my diff is just "stiff" or if it indeed IS a VLSD?

Also, I went ahead and did the swap anyways since I discovered this almost at the end of the swap... my car feels GREAT and I can't break traction anyways on dry pavement....so should I even care about the VLSD?

I had a Pontiac Grand Prix ( FWD ) that put down 357whp and I would lay 1.9 60 foot times on skinny *** crappy street tires and it had an open diff...has anyone here really noticed a difference going from open to vlsd in drag racing?

 

I opened the plug where you drain the oil and I can see the solid differential ( VLSD ). I did some searching at it seams sedans are the ones that don't offer this ( I had a sedan before which explains where I heard this ).

So now the question is...

Will I miss it if I don't do any time of racing that's not straight line racing? I come from having a Grand Prix and a GTI and both of them with LSD's offered virtually no advantage over the open diffs in drag racing...in circuit style racing it's a different story.

 

For drag racing, VLSD doesn't do squat and most other LSDs won't do much either. For one, they're not 50/50 splits and secondly, most LSDs don't engage immediately. Like you've pointed out, the primary purpose of the LSD to limit tire spin when a tire becomes unloaded in a turn, usually a tight off camber turn. For you're type of driving (ie mostly street, some drag, no tight course road racing), you'll be absolutely fine with an open diff. You can combat some of the inner wheel spin by running sticky summer rated rubber. Tires are alway key. Without good tires, most everything else is pointless.

I've been through 3 auto-x events this year in my open diff 03 sedan. I'm running 18X8 rims with PZeros and I haven't had any major issues with the open diff because the tires are so grippy. However, for $250, I can pick up an VLSD 3.3 diff so I figure why not. It can't hurt.

So how was the swap? It looks relatively easy. Anything I should be aware of during the swap?

 

BTW, you GTI and GTP hooked up well largely because they had 65% of the weight over the tires.

 

I figured as much...

The swap was SUPER EASY. Moving around the extremely heavy pumpkin was the most difficult part because I have a small jack and the pumpkin would try to fall of the jack...lol. I don't think you HAVE to remove the sway bar and mid pipe section if you have a good jack ( maybe a transmission jack? ) but since mine sucks I removed those parts to make extra space ( took only a few minutes extra so why not ). All in all, you can do the entire swap in about 1.5 hours if you don't stop at any moment. I took two hours with a few breaks talking on the phone and getting on the internet and what not. This was also with zero power/pneumatic tools and on the floor of my garage.

As for performance...it feels pretty darn good. It's obviously not a huge difference since it's only about 5% steeper but 2nd gear feels soooo alive...it's the best gear imo.

 

Well, I went for a ride tonight and did a few runs from a stand still. Looks like at night I can break my tires loose for a second or so on the same road where my car would NEVER spin it's tires before on the 3.3. I COULD attribute this to one wheel tire spin, except the rear of the car tends to go a bit sideways which means that both tires are apparently spinning and makes me believe that it could be the steeper gearing...makes sense?

 

I too am getting ready to swap out my 3.3 for a 3.5 both with VLSD. I don't know if this is relevant, but here are a couple of pics from the marketplace. Both diffs are 3.3, but the first pic is one with VLSD and has the vacuum hose attachment on top (the curved metal pipe). The second diff does not have VLSD and is missing the vacuum tube attachment. Looks more like it was sealed at the factory than replaced with a cap or something. Maybe that's a visual clue as to which diff is which. Did your stocker have the vacuum tube?






Do you feel the swap was worth the $$ and time invested? I got a really good deal on mine and will have it in in the next week or so. I'm curious to get any feedback you want to share.

 

been looking for one of these for a while.

the steeper gearing is likely the reason you break tires more easily and the lsd is gonna be your culprit in sliding sideways some

the stock lsd doesn't activate as much as all the aftermarket options, which are much better

 

see what the difference is on the track

 

Here's my 03 with the OEM 3.3 gears and open diff. No trouble spinning them, leaving two equal tracks of rubber, and getting the rear to step sideways.

 

Both of my pumpkins have the tube, even though one is vlsd and the other isn't.

It was definitely worth it. It cost me $200 ( shipping to PR is what has kept me from getting one of these a long time ago...found this one locally which is super rare ) and took two hours of my time ( which is more than it could have ) and car feels like it gained more from this than any other mods I've done ( Spacer, test pipes ).

 

Wow you got a better deal than I did, but I'm glad to hear you are happy with the swap.

 

Thanks! Keep in mind mine is not vlsd so yours might be a better deal. The problem is that I couldn't get a pumpkin shipped for less than $500 total which at that point wasn't worth it to me.

 

especially since the stock VLSD isn't that great...if you're gonna spend extra $$ on VLSD go aftermarket.