Ok,
I'm having a senior moment now so bear with me. I would like to know what is the difference between the German Panther D and the G models?
Is there a (big)or(small)difference?
Can someone for lack of a better phrase,spot the difference a mile away?
I know stupid question but for some reason I just can't think tonight. lol.
Thank you.

The two most visible differences are raised fan on the rear deck and the squared off mantle to eliminate the shot trap, although I can't remember if these appeared on early or just late Gs. I'm sure others will chime in.

The D has a dustbin cupola, letter box machine gun opening on the front plate, driver's vision opening and the level sponson side with the kink towards the rear. G has the lower cast cupola, ball mount machine gun, driver's periscope and the upper hull sloping to the rear.

As the D was actually the first production version, followed by the A, and the (late) G was the last prod version there are quite a few differences. Suggest you pick
the war period you want to model, then go with the version of Panther to build

Early D's road-wheels also had twice as many bolts as later ausfs.

And so far everybody has been off.
From first to last production the basic features:
Ausf.D *Kursk): dustbin cupola, hull visor and machine gun visor. Ports on side of turret half as many bolts on rims of road wheels, jack mounted under single pipe exhaust stacks. Binocular gunners sight. Zimmerit appears late 1943.
Late Ausf D. cast cupola all rest same. Telescopic gunner's sight.
Ausf A: machine gun in hull, single and triple pipe exhaust and jack between exhausts. All turret side ports eliminated.
Early Ausf G: angled rear hull, single exhausts, hinged driver's hatches, driver's periscope. Tool storage changed on hull sides. Driver's visor eliminated.
As production of G continued raised rear deck fan, flameless exhausts and chinned gun mantle introduced, as is close defence weapon and pilzen mounts on turret top. Zimmerit discontinued Sept1944.

However, chinned mantle not universal on late production tanks as existing parts were used. You could even see a chinless mantle with raised engine deck fan and earlier exhausts. Panthers varied according to factory and time produced.

It should be mentioned that older tanks were kept in service so an early Ausf D was encountered in Italy in 1945 along side a last production Ausf G.

That's just the bare outlines but it should be a start. I'd advise getting any number of books on Panthers or even a basic reference on German tanks. Just something simple like an Osprey vanguard to help you tell things apart.

I believe the transition between D and A was the cupola, not the MG slot to kugelblende. And yes, you can spot the main differences a mile away

Not exactly. The original production wheels had 16 rim bolts. These failed too often, so the wheels were modified to have an additional fastener (either a rivet or a bolt) added in between the existing bolts, raising the total to 32. Many Ausf. D tanks had mixed sets of these wheels.

The revised production wheels (from summer, 1943) had 24 bolts per wheel. These were seen on late D's, Ausf. A's and Ausf. G versions.

Hey Jody,
Mike from the Upper Valley Club, coming late to the conversation.
Looks like folks have pretty well covered it.
If you are around this summer, you're welcome to borrow any of the Panther library I've accumulated. Shoot me an email address and I can send pics from the Achtung Panzer volume.

Yeah, the difference is pretty big.

Visually, the letter box mg and vision flaps, turret cupola, the extra facet on the rear of the hull sides, and exhaust pipe differences tell the tale pretty quickly. The tool layout is somewhat different as well.

What have you got planned, Panther-wise?

If you are only concerned about D/G, the hull is the easiest way to differentiate, although the turret construction was different so the sides of the internal mantlet differed. The A and G used the same turret (although it evolved over time) as one can tell because both used the same drawing numbers.

The D and A hull had a hinged port for the driver in the glacis, the G didn't. The D (and A) hull upper side plates changed angle at the lower rear to vertical, whereas the G upper hull sides were made from a single plate.

Most of the other point mentioned are clues but not necessarily diagnostic.