Ricky_Bobby

Guys,

I have had my 93 LT1 A4 2.59 for two years now and I cant stand the lack of acceleration anymore.

I found a D44 3.45 carrier and batwing at Contemporary Corvette near my house. About $1,100-1,200. Unknown mileage.

I am looking to purchase this ASAP.

My question is do I need the drive shaft and C-Beam from the D44...I researched the forum/archives and found conflicting information.

Some people say the D36 C-beam and driveshaft will work. Maybe drill the C-beam. Some also have to shorten the shaft.

Other people swap the C-beam and drive shaft because the D44 is shorter than D36.

What is the best option here???

Also, should I check the diff and if OK fill it with fluids and install?? OR should I tear down and rebuild??

I have two friends who are commercial mechanics and also have corvettes so we can do the install and rebuild no problem.

Thanks!!

aboatguy

YES buy the rear end with diff, batwing, c beam and driveshaft

If I remember correctly the c beam and driveshaft are about an inch different in length between D44 and D36.

If you have two friends with the skills and desire to tear the diff apart I'd do it when its out since theoretically you'd never have to touch it again.

PLRX

It would be cheaper if you swap the gears instead of buying a new rear axle, C-Beam, and drive shaft.

I thing 3.45 would give you maybe 15-18 MPG on the freeway.

Ricky_Bobby

I was going to swap the 2.59 gears for a set of 3.54, but if I am going to spend $500-600 in parts just for ring/pinion and rebuild for the D36 why wouldnt I want to spend $1,200 for a used D44!

I only have intake/catback and PCM4less chip with 82k on the clock. I am think long term...If I rebuild the 350 and 4L60 in the next 2-3 years I want it to handle the 400hp and 315 street tires

Will the D44 driveshaft and C-beam bolt up the auto 4L60 tranny??

I dont want to have to modified yokes or anything. Hope this would all be straight swap/upgrade.

James93LT1

You will need the dana 44 third member, bat wing, C beam, and drive shaft to do the swap.

Scroll down the link below and there is a pic of the dana 36, dana 44, drive shaft, C beam. The shorter of the two is for the dana 44. The dana 44 has a longer pinion than the dana 36.

http://forums.corvetteforum.com/1582811609-post1.html

You will also have to swap out the manual yoke on the dana 44 drive shaft, with your auto yoke on your dana 36 drive shaft. The yoke is different between the auto trans and manual trans. You also might as well install new u joints on the dana 44 drive shaft while you are there.

PLRX

Analyse all the numbers, and save your cash.

D44: $1,200 (does it include the batwing, and bushings?)

D44 Driveshaft: $250.00

D44 C-Beam: $73.00

I don't 400 HP would crack a D36. Am I wrong?

James covered the yoke difference. Are the C-Beams for the D36 and D44 the same parts?

WVZR-1

You only need to ask yourself if you really "want/need" the 3.45 ratio and also if you really "want/need" the D44. If you're that close to Contemporary I believe I'd see if they have a 3.07 D36 and try that first. There will always be 3.45 D44's out there. Always! If you like the 3.07 you're all set, if not it will always likely bring what you pay out.

CC should know the car the 3.45 was removed from and be able to supply the mileage when they bought the salvage unless it wasn't from a complete car that they bought salvage on.

Removing the cover might be a good indicator of the condition of the 3.45. You can check things like pinion drag, unless it been pressure washed the condition of the seals (3) might hint it's condition. The year is also etched on the differential and the ring/pinion is date coded. There's no lack of information.

If I were doing the D44 I'd do it with the D44 beam and drive-shaft and just swapping the slip yoke while doing u-joints. A balance would be good.

If I weren't rushed I believe I'd consider the wait and maybe try a 3.07 first.

TA

I really think it depends on the OP intends to use the car for. If he just uses the car on the street then I completely agree with you that he should stick with a D36 and save the cash. If he plans to hit the dragstrip regularly and use sticky tires then I'd go with the D44.

I'll admit that even a D36 could last for awhile at the track. That being said I know, first hand, you can grenade a D36 with far less than 400 HP (did it twice actually). I have a D44 now.

383vett

Go for the 44. It'll hold up for future upgrades. You can run stickies and not worry about it.

Ricky_Bobby

Thanks for the input guys.

My future plans are to at least put in a hot cam and port/polish the heads, but with 82k on the clock I may just save up another year or two and do a total rebuild with a bigger cam.

I dont intend to drag race, but I used to work at Englishtown during high school and college. I also would like to try a few track days.

I know that I wont be happy with the 3.07. I am thinking the 3.45/3.54 would be perfect.

I just would hate to spend the time/money on a 3.54 D36 and break it cause I keep punching the gas and smokin the tires. I also do have somewhat sticky street tires. Grand Sport replica's 11.5 x 17 with 315 Nitto 555 on the rear.

aboatguy

The c beams are about an inch different in length.


I spent the little bit extra for the D44. IMO its the same as upgrading from a 10 bolt to a 12 bolt on a chevelle.


Just a little insurance.

Mike

vetteoz

http://www.joby.se/corvette/mods/2001-0X11_diff/

Ricky_Bobby

I think it's settled. I am just gonna go D44. I will call and stop by CC this week and check out their selection.

I believe the $1,200 was for the carrier and batwing, but did not include the shaft or c-beam.

Zip and other places have a fully rebuilt D44 for $1,000.00 plus an $1,800 core charge. But i dont have a D44 to send back so it would be $2,800.00!!

Boatguy - thats my exact thought about 10-12 bolts...you wouldnt build any SBC or BBC and put a 10 bolt behind it

cttech455

I would think long term and ditch the D36 myself. When I bought my car (1985 with 4+3) I switched out the stock 3:07 gears with 3:75 to one gears, and discovered a cracked bearing cap in the rear end. That was with a Dana44 and a completely stock l98 with 255 wide tires. I'm sure the car was abused. the nose on the D44 housing is slightly longer than the D36 so the driveshaft and C beam are a little shorter to compensate. I changed over to a 4l60e transmission and the spline count was the same as the 4+3. There was no need to change out the yoke. The driveshaft slid in.

vetteoz

Depends what car his new D44 driveshaft comes from.
If from a ZF6 car then the yoke is different

cttech455

Yes the ZF6 has a 32 tooth spline count, but I mentioned that my driveshaft came from a 4+3. Just pointing out that having to switch the yoke is not necessarily a rule simply because the doner driveshaft came from a manual transmission vehicle, the driveshaft from 85-87 vehicles have the same spline count as the 4l60e.

vetteoz

Do you gamble?
Chances of getting a driveshaft from a 4+3 car; 4/12
Chances of one from a ZF6 car; 8/12

Ricky_Bobby

UPDATE

Went to Contemporary Corvette today during my lunch break.

They dont have any D44's laying around. You basically have to put a deposit down and they will pull the D44 out of a manual C4 in the yard.

It is $1,165 for the carrier and batwing plus $300.00 for the C-beam and driveshaft. So $1,465.00 for a complete D44 swap.

CC will call me in a few days when they pull a D44. I can go and inspect the entire thing before I pay the balance and take delivery.

They give a warranty..believe it is 30 or 90 days.

Hopefully they can tell me what year C4 it came out of and how many miles.

vetteoz

Like Dave said above , the factory info is underneath.
Late cars are stamped , my '87 had the numbers hand etched

WVZR-1

It seems you should have a choice of what they have. It seems a bit backwards in the selection process. Might be the way they do it but I would have thought the "choice" to be yours. They could actually have a 3.33 and just pick a different one. All D44's aren't 3.45's. I've never heard bad about them but the sale of the D44 is not the way I'd have thought. If they have 6 they'd present you with "choices"! If they're in the wholesale salvage sales business they're required to supply VIN and history so to speak of the sale on an invoice. Look at it this way - if they have 6 and you were them selling the way you explained you'd naturally sell the higher mileage/older pieces if the opportunity presented itself. Ask how many they have!