So here's the question: Will a D44 complete rear end assembly (rotor to rotor) bolt in place of a complete D36 assembly. Are the transfer beams the same and are the drive shafts the same. Will any modifications be required other than a tune to recalibrate the speedometer for a different gear ratio? Both cars are 1994 Corvettes...doner car was a 6 speed manual....receiving car is an automatic.

Thanks in advance.

 

Had this done 2 years ago on my 95. The snout (nose) on the D44 pumpkin is a little longer thus the drive shaft is a bit shorter so use the one from the donor if available. I also chose to buy a new yoke and so the driveshaft was re-balanced. .Note that there are several folks on here who have done this multiple times and report that they did not have to shorten the drive shaft from the D36. The holes in the C-beam are also in slightly different positions.

The "kit" I bought came out of a 96 LT4 and came with the driveshaft and C-beam so I just used those. The D44 batwing was a direct fit. I had new bushings installed ....oh and I had the batwing power coated.

 

Thank You Sir...I suspected there might be a difference but you have confirmed it. Are the bolt holes on the C-Beam the same on the front where it attaches to the transmission?

 

I'm sorry I don't recall if the positions were different only in the back. Because I had the one that came out of the 6-speed along with all of the rest of the items we elected to simply use the one out of the 6-speed.

I'm sure that there are other guys on here who will know as this has been covered a number of times in the past.

 

Depends on what year D44 assembly. 88-96 is a straight swap. I believe 85-87 will bolt in but there are differences in early and late suspension and brakes. The wheel offset is different between 84-87 and 88-96. The batwing and housing bolts in reusing existing D36 suspension parts. You will want M6 driveshaft and transfer A4 yoke. The C beam is either modified with additional bolt holes or replaced with M6 version.

 

D44 pumpkin require a D44 batwing, a D44 c-beam and D44 driveshaft. Transmission yoke the automatic driveshaft can be moved to D44 driveshaft.

These parts as a set will fit on any C4 Corvette.

If you include everything "rotor to rotor" it gets complicated as there were many changes over the years, but in your case where both are from the same year everything will fit. I am not sure that is is easier to change everyting compared to changing only the center section.

 

Make sure you get an alignment after it's in.

 

You only need to swap the batwing and center section. You can reuse existing knuckles and halfshafts. I would recommend installing new ujoints while you have it apart, and check wheel bearing play. Use whichever bearings are the tightest. You need to use the m6 cbeam and driveshaft and switch the auto yoke back on it. New ujoints on driveshaft would be a good idea too. Maybe even a new rear seal in trans. It’s a lot easier to do this now than waiting till it’s all back together and then discover a problem.

 

Thanks...these are all things I had suspected but was not sure of. I am at a cross roads on which way to go with this and having read the responding posts...I'm leaning towards just replacing the Center Section with a D36 that has 3.45s~3.54 gears in it that is completely rebuilt and guaranteed. While I have it apart I will replace all the bushings with the most compliant poly pieces I can find and probably the u-joints as well...plus anything else that needs attention. I don't plan any serious power upgrades for this car...such as a built 383 or a LS/LT swap....but I do want to give it some more "snap" on the street and gears are the easiest path to that. I'm running 2.59s now and know what the changes I am about to make will do to the car. It's been my experience that to get serious throttle response, you need to get that 1st gear transmission/rear end ratio in the 10-1 neighborhood to really get the car moving from a dead stop. The 4L60E has a 3.06 1st gear and a 1.625 2nd gives you 10.83:1 and 5.75:1 respectively..which is stout enough for me on the street. I might tear into the "Top End" at some time and clone a LT-4, but that's about it. This is my "retirement" toy and I don't plan to race it. We belong to the local Corvette Club here in Ocala, Fl and mostly do group cruises and "One Tank" drives to Daytona or Clearwater on nice days we can run with the top down. Reliability is at the top of the list for me...but I do like to have fun.As these cars get older...there are always "little things" that have to be done, especially with a Convertible. I still need to do the Batee procedure so I can read the speedometer without my Polarized Sunglasses on. Also I need to dig into the steering column to repair the "High Beam/Low Beam" switch and upgrade the Headlights...still running the original Halogen set up which is very easy to "overdrive" at night.

All things considered, these cars are a great "Bang for the Buck". They were well engineered, years ahead of their time and in my opinion some of the best looking/driving cars to come out of detroit in the 20th century.

Thanks for all of the responses and I welcome any additional thoughts or suggestions.


1994 Corvette 74K Miles Base Motor, Automatic

Twenty Six year old '94 LT-1 Automatic

 

If the M6 donor is a 'known good' 3.45 I'd be inclined to do the D44 vs the 'build' of a D36 (particularly yours). Yours in a currently drive-able condition has resale value. A build of it and that goes away! Very dependent on what's available from the M6 donor it might be similarly priced.

The M6 donor I assume isn't in a car currently! If it is and able to be driven before the buy - I'd certainly consider the D44 before a build of your D36. A 'vert with a 'whiney' D36 would get old very soon! Many do regardless of who the builder is. A 2.59 requiring the thicker gear might be more inclined to be a 'whiner'!!

Your 'location' hints maybe you should have a conversation with @C409 - I believe he could maybe advise !

 

[QUOTE=WVZR-1;1601537391]If the M6 donor is a 'known good' 3.45 I'd be inclined to do the D44 vs the 'build' of a D36 (particularly yours). Yours in a currently drive-able condition has resale value. A build of it and that goes away! Very dependent on what's available from the M6 donor it might be similarly priced.

I agree with this. If your donor is a 3:45, I would swap them rather than build a D36. I have rebuilt several D44 and D36 and swapped gears. It is much easier to swap rearends than to remove one to rebuild and replace. Unless you have the tools to rebuild it yourself, it will be pretty expensive. Even if the condition of the donor D44 is known, you should remove the batwing to inspect and change the gear oil anyway.

 

[QUOTE=IBVETN2;1601537482]I'm in a similar boat, I have a D36 with a 2.59 and I bought one with a 3.07. My plan either way is to sell the 3.07 rear to offset the cost of two options.

1) switch to Richmond 3.45/3.54 gears and use the 2.59 rear.....what is a ball park estimated cost to go route?

2) Do the D44 conversion (approx $1K for pumpkin, C-beam and driveshaft), would it be a good idea to have that rebuilt before install? Also what do you thing is a good estimate on installation?

TIA

 

[QUOTE=IBVETN2;1601537482]I understand...Zip sells a complete "Bolt In" Rebuilt D36 3.54 with a 3 year unlimited warranty for $1000 plus $400 Core Charge. I plan to keep my original "just in case". I have purchased several things from Zip in the past with no issues...as have a number of guys in our Club.I plan to keep the original D36 2.59...to have the original in case I sell the car.

The swap "Total Rotor to Rotor" is 2 hours from me and the seller "Says" he drove the car before he pulled the Rear End and Transmission.

Again...all GREAT info and I really do appreciate the input.