I know I've seen information on this and have searched the forums to no avail. Could someone provide information or a link on converting the batwing to a D44. Thanks.

 

it ain't happening.

 

d36 batwing on d44 using adapter plate

this was originally developed to beef up the d44 by reducing case distortion under severe usage but makes a great d36 adapter

 

Do you have any more info on this? I was always under the impression that the 44 wing was stronger and not convertable. At the price of 44 wings, this is VERY interesting!

 

this is beyond interesting. It's drifting into facinating.

I have been under the impression that the D36 was totally incompatible with the D44... Period. I stand corrected... whether it's a good idea remains to be seen, tho.

 

As I understand it, a D44 carrier with a D36 batwing isn't stronger because of the D36 batwing. It's stronger because of the forged steel adapter plate. I would presume, therefore, that if you made a forged steel spacer between your D44 carrier and D44 batwing that would also be stronger than the original D44 comdination.

 

long ago, not too far away, i wanted to change the gears in my d44...FSM sez to spread the case using a ''special'' tool which even the dealer did not have, so i made a spreader of my own; put the backyard wonder on the diff assy along with a dial indicator to see if the thing would work; before the drawbolts were under minimal tension, the case opened to the max suggested in the FSM...obviously some added rigidity was desirable...did a little brain workout ( a mnemonic exercise really, industrial gear reduction boxes were the inspiration, ''bulkheads'' are common practice in those) and took the idea to the local machine shop, where the apparition became a gizmo...small irritant was the gizmo pushed the d44 bat back a tad, still within acceptable limits, but the spare d36 over in the corner of my shop proffered an escape -- a bat that was thinner by the thickness of the gizmo..viola!!!

the d44 ''outriggers''are a bit fatter than the d36, but has anyone broken a d36 bat in service?--(excluding crashes or destruction by other external forces, of course)

 

There are different batwing designs, at least for the D36.
According to a picture from a book I have all D36 should be of the 'stronger' design, and my early 1984 ( #902 of the 51547 built as 1984 ) had the improved design. I also know that there are a lot of later C4 Corvettes out there with the weaker D36 design.



And now look at my D44 ( on top ) that replaced the 'strong' design D36.







The d36 batwing posted above is the weak design.
[QUOTE=redrose]d36 batwing on d44 using adapter plate

[/QOUTE]

 

I certainly with that, what the hell is wrong with using a normal DANA 44 rear cover??
In the pic below you see my two diffs, top is the DANA 36 that was factory fitted to my 94, and below is the DANA 44 i bought to replace it with to improve the durability. You may notice how much thinner the rear cover-to-chassis arms are on the DANA 36.


Secondly, wouldnt this spacing device mean that either manual or auto C-beams are now an incorrect length???

 

Case,

I believe the purpose of the D36 batwing to D44 diff is its thinner so you can use a steel plate to strengthen the case.

IMHO if I were busting D44s I'd be looking for a replacement made out of steel or iron vice fabbing something for the aluminum diff.

 

Mike!!! Long time no see mate!!!

 

I saw a video on here a while back where someone did break the batwing of a DANA 44 on a drag strip, so id imagine the DANA 36 batwing wouldve also failed under that load.

 

i have heard of half-shafts breaking and busting the batwing, was that what happened in that video ?...at the junction of the bat outrigger to the center, my d36 outrigger is abt 2-1/4'' wide, my d44 outrigger is abt 2-1/2'' wide, both abt 1/4'' thick --not any substantial difference in strength imho..... welding a 1/4 x 2'' flat bar to the outrigger upper and lower flanges would more than double the outrigger strength, cost and weight negligible....but is it of any benefit if the member is not subject to failure as is ?????....does not seem to be a weak point based on dearth of reported failures

midplate (adapter) does NOT affect the length of the c-beam rear axle location, driveshaft length, or anything else IF the d36 bat is used....if the d44 bat is used, the bat-to-body mounts will need minor rework but the spring and inner tie rod relocation is prolly of no concern...my prototype plate was 1/4'' thick in contemplation of retaining the d44 bat, but change to the d36 bat allowed the plate to become 3/8'' thick and maintained everything else in original location.

plate material that i used was 6061-T651 alum.....yield of 6061-T651 is 37 Ksi...commonly available steel plate is 1015 alloy, yield 29 Ksi....you could use 7075-T651 alum, yield 73 Ksi.....steel or 7075 alum may be undesireable due to corrosion potential....6061-T651 is a bit pricey, be certain that your supplier cuts with a saw and does not ''plasma'' burn to cut as heat affects temper (strength)

 

Redrose,
This is exactly what I'm talking about. Any more information on the spacer plate? Are the top bolts the only mismatch that need to be modified? How thick is the plate? I'll search more. Thanks for the replies.

 

there are (9) bolt holes total in the midplate/adapter... you can use the adapter plate as a template to drill (4) new holes and elongate (1) existing hole in the d36 batwing...at the bottom on each side of the adapter and all the existing parts there are two suspension pick-up points (bolt holes) for the lower struts which are in the same location for both the d36 and d44...these (4) larger holes are your alignment references for drilling the (4) small holes and elongating the bottom centre hole in the d36 bat .
some d36 bats have slightly smaller bolts and respective holes to mount the lower struts and you may want to consider enlarging the (4)d36 bat holes and corresponding suspension bracket bolt holes for the lower struts to use the larger d44 bolt.
existing d36 bolt holes do not need plugs as they are blinded by the adapter plate....stuff em with alum foil and finish with j-b weld if you want to ''disappear'' the unused holes.
the d36 has a push-in (NOT threaded) plastic vent ''mushroom'' that you may find inconvenient to leave in its present location....you can plug the existing vent hole and drill/relocate the vent as shown in the pic below or glue ( rtv or epoxy) a thin alum plate over the existing hole with one edge of the plate raised to allow venting.
plate thickness at 3/8'' puts all dimensions back to stock d44 (almost) when used with the d36 bat.

shows relocated vent and one of the cover new and old bolt holes

 

Almost???

 

the total ''stacked'' dimension at the lower strut bolt holes was measured with an .001'' increment dial indicating caliper and worst of three readings was found to be .007'' different IIRC from the d44 case+d44batwing vs the d44 case+midplate+d36 batwing....the lower strut brackets ''squeeze'' in to fit the oem assy d36 or d44 anyway, so the .oo7'' measurement was taken as ''acceptable'' based on the extensive mechanical backgrounds of the evaluators....other dimensions such as tie rod bracket positions were measured using a machinist's steel scale and were found to be very close as far as could be determined using that crude device, and again were considered ''acceptable''....the rubber bushing outer batwing mounts were too flexible to be measured with any accuracy, but as both the d36 and d44 batwings came from production vehicles that can accept either unit, dimensions were not established.

''identical'' to me would mean that i cannot measure ANY difference and that was not the situation here....hence i refer to these as ''almost''....good enough for the girls that i go out with?--i think so.....you may have other opinions

 

I'm not sure I completely agree with this. I'm not sure exactly what specifics make a D44 stronger than a D36, but from my owm personal experience I'd say the batwing is one of them. I managed to twist up a D36 batwing pretty good at the dragstrip, including breaking the support bars that run between the top and bottom rails. My current D44 (on the same car) has managed to hold up well, at least externally (I did grenade the internals once ). My failure on the D36 could have been a freak thing, but it sure makes me think the batwing on it was weaker. BTW, my car isn't a high horsepower car and doesn't have a ton of mods, but it does see quite a bit of track time.

 

hooray, someone with real experience (anybody else,please?)... will be dropping a big block in during the winter and have resigned myself to replacing the rear axle with higher torque rated unit (as yet unchosen), appreciate reinforcement of that decision.

the d44 and d36 (newer, weak style?) batwings are visually quite similar...breakage of the diagonal web bars that you report would seem to be a potential for both .....perhaps the old(?) heavier webbed d36 as shown in joBy's post (above) is superior to all ??

any more details on your diagonal bar failure ??....severe wheel hop?...any marks on the lower flange that might indicate previous impact to that ?....any known previous ''excursions'' into harsh terrain ?...was the car trailered using tie-down straps or chains thru the batwing web spaces ?....any clues?

interestingly we have come full circle...grenading the internals of your d44 might be prevented by reduction of case distortion via a reinforcing mid-plate ??

 

I very much doubt the DANA 44 internals are going to be held as strong with the DANA 36 cover. I wouldnt be saying hooray that you have found someone with experience on breaking a DANA 36 batwing, rememeber the bloke said he DID break it, not he didnt break it. If he broke the batwing without the plate, 5 will get you 10 he wouldve broke it with the plate.