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Topic: Which Dana rear?

in Forum: C4 Driveline Components

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Which Dana rear? (1/11)
7/9/14 6:11pm

cco
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Joined: 8/16/2013
Posts: 191

......do I have on my '94 auto? I believe it's a 36 but not sure. I do know it has the optional 3:07 gears.

I'm considering an upgrade to 3:54 or 3.73's -- Any thoughts on the subject?

Will those ratios fit into the Dana 36 housing and is the housing strong enough for just every day driving?

Any suggestions as to where to buy such a diff if I were to change mine out? (I'm in Canada)

Checked my option sheet and the car has G44 (3:07) and G92 (Performance Rear).

|UPDATED|7/9/2014 3:11:33 PM (AZT)|/UPDATED|

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Re: Which Dana rear? (2/11)
7/10/14 10:08am

hcbph
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Minneapolis, MN - USA

Vette(s):
Purchased a 1986 Convert August 2013, Bright Red color with a black top, it'd already received a Tremec 5 speed upgrade along with a disc upgrade prior to purchase.

Joined: 8/16/2013
Posts: 53

Don't take this as absolute fact as it's something I've read in the past, but in the earlier year Vettes the automatics came with the 36 while the manuals had the 44.

The question is why are you considering the change in ratios? If you change the gear ratio in addition to the physical change you also have things like getting the speedometer recalibrated and the potential loss in gas mileage.

I suspect something like a 3.54 ratio may be on the top end for a 36 rear end in fitting the case but I'd suggest you talk to some gear vendors to first confirm that.

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Re: Which Dana rear? (3/11)
7/10/14 10:21am

cco
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Posts: 191

Just wanted a little more 'oomph' off the line -- Yes I would have to have the speedo recalibrated and would sacrifice a little gas mileage but hey, I'd love a little more performance.

Still investigating but from what I've found out it's not cheap by any means and probably the money would be better spent on other upgrades.

I also read that the '36' was installed on the auto and the '44' on the manual trans. I've also read that the 36 is a stout rear in itself and will stand up quite well in the long haul.

Thanks hcbph .. I appreciate the views.

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Re: Which Dana rear? (4/11)
7/21/14 7:16am

REDVETTE85
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NORTON, OH - USA

Vette(s):
1985 C4 red, 1985 C4 Black and dark gray

Joined: 7/9/2012
Posts: 111

I went from the 3:07 to 3:73 in my Dana 44 and dollar for dollar that was the best money spent

There are all kinds of thing that the 1,000.00 -1250.00 could be spent on.

1st thing is finding some one local that is experienced with it ,then pull the center section and drop it off REPLACE ALL THE U-JOINTS WITH SPICERS and have Fun smoking the crap out of the rear tires and by the way check out the C-Beam reinforcement plates your gonna need them and another set of tires HAVE FUN !!

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Re: Which Dana rear? (5/11)
7/21/14 12:02pm

jimmymack
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West Chester, PA - USA

Vette(s):
1995 Torch Red Coupe

Joined: 3/20/2009
Posts: 702

My .02....if you have the 3.07, I'd suggest that a better cam, 1.6 roller rockers and springs and head/manifold port matching will give you more. Throw headers in there, you'll gain plenty of extra "oompf" that you'll feel, not only seat of the pants but on the drag strip, if you ever go that way.

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Re: Which Dana rear? (6/11)
7/23/14 5:00pm

396c4
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Joined: 12/7/2011
Posts: 219

Either one is a start but it's a system. I swapped my 36 for a 44 which came with 3:45 gear. Overdrive on the highway is still around 2000-2200. Bigger came does better higher so converter and a more gear work better together, especially with higher stall converter. Mine is around 2800 but will flash to 3000. Bring it up to around 1500 and let her rip, it will flash to the stall and fell like a big rubber band... just keeps on going up to the current red line at 6200...

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Re: Which Dana rear? (7/11)
7/30/14 1:49pm

FLDAVE
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1953 1992 BLACK ON BLACK

Joined: 11/22/2009
Posts: 60

All '84's came with a D36. All '85 to '96's girl vettes with a slush box had D36"s with 3:07 standard. All '85 to '96 boy vettes with stick had D44's with 3:45 standard. The D44 has a bigger gearset, bigger bearings, bigger pinion shaft. The reason for this is simple. There is no parasitic torque loss through a manual tranny (except for a little friction) so more torque is input to the rear. The theory was the auto tranny will grenade itself long before the rear end. So they could save a few coins with the D36 in the auto's. You would think it would be cheaper to just buy D44's and put them in everything instead of inventorying two. But the bean counters calculus is beyond me.

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Re: Which Dana rear? (8/11)
7/31/14 3:18pm

cco
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FLDAVE said: All '84's came with a D36. All '85 to '96's girl vettes with a slush box had D36"s with 3:07 standard. All '85 to '96 boy vettes with stick had D44's with 3:45 standard. The D44 has a bigger gearset, bigger bearings, bigger pinion shaft. The reason for this is simple. There is no parasitic torque loss through a manual tranny (except for a little friction) so more torque is input to the rear. The theory was the auto tranny will grenade itself long before the rear end. So they could save a few coins with the D36 in the auto's. You would think it would be cheaper to just buy D44's and put them in everything instead of inventorying two. But the bean counters calculus is beyond me.

LOL indeed Dave -- GM's thinking (or lack of) has been called into serious question lately over many things.

As I've heard many times b4: what you suggest makes too much sense.

Thanks for the clarification. I have the D-36 with a 3:07 R&P.

|UPDATED|7/31/2014 12:18:22 PM (AZT)|/UPDATED|

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Re: Which Dana rear? (9/11)
8/1/14 10:19am

I don't believe the 85-96 D44's were standard with 3.45 gears. The info on my 86 L98 originally came with the 4+3 (M44) and the build info shows option G44 which as I understand it is the D44 rear with 3.07 gear ratio. That matches a number of things I've read regarding transmissions and rear end ratios.
I thought 3.07's were the standard gear for manual shift Vettes in that time frame though there probably were other ratios available either as options or on high performance models.

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Re: Which Dana rear? (10/11)
8/1/14 9:52pm

cco
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jimmymack said: My .02....if you have the 3.07, I'd suggest that a better cam, 1.6 roller rockers and springs and head/manifold port matching will give you more. Throw headers in there, you'll gain plenty of extra "oompf" that you'll feel, not only seat of the pants but on the drag strip, if you ever go that way.

I'm thinking more along those lines now.

I priced a s/charger for my C4 and $8k is a little out of reach. Your suggestion of a cam, rr's, port matching and headers should be a lot less with a nice bump in power.

Good suggestion JimmyM.

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Re: Which Dana rear? (11/11)
8/5/14 6:14am

86er
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1986 C4 Corvette Coupe, Medium Blue Metallic

Joined: 5/13/2012
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Hi, I have the 3.07 in the rear of my 86 Auto, I like this ratio for my use. The 3.07 was the performance option ratio for the model. I left my rear as is & played with the engine a little as I like the torque I have which is 350 horsepower & 547 ft/lbs at the rear wheels. It idles as smooth at 800 without a stall converter & gives 32 mpg on a trip. Fry tires the good old fashioned way

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