I've looked at them, according to the 3.55 writeup, it states that the 3.55 is the smaller of the two.

from the 3.55 writeup, "5. Place the bellhousing clutch side down on your workbench, place the 3.55 differential in the housing. If you confused the two differentials because you are not organized, the 3.55 is the smaller of the two ring gears."

Well, i can't tell. I'm not a dumbass damnit. It looks like the 3.94 has ID Marks that correspond between the differential splines and the output shaft splines.

There are also raised, stamped numbers & letters on the differentials that may distiguish them so you can get the correct one if you need to. There has to be a damn difference...

this is a pic of the 3.55. See how the output shaft splines do not have ID Markings? (on the center of the splines)

The 3.94 does. ONE of the differentials have matching ID markings like the .94 does, the other does not. Could this be the match?

So, it could be save to say that the differential from the 3.94 will not work in a 3.55 trans?

Sorry for the hijack

Back to the original question though, if you have the part number on the outside of the trans you could check that and see if it matches with the right part #. http://www.neons.org/forumdodge/trans.htm

Hope that helps.

Originally posted by barza21
So, it could be save to say that the differential from the 3.94 will not work in a 3.55 trans?

The diff is interchangeable. You just have to swap out the ring gears.

so you're saying that the amount of teeth on the ring gears are different? The 3.55 diff has a smaller amount of teeth?

If that's the case, i have a favor to ask of someone. Whoever has a spare 3.94 stock diff layin around, please count the teeth on the ring gear and post up :( thanks in advance.

I asked the question the wrong way, sorry... lol :+

Mikey, I will go do that right now.

also, tell me if your .94 diff has hash mark "ID markings" on the ring gear. They're little notches dug into the center of the splines...

Ok,

Answering your question Mikey, the 3.55 and 3.94 ring gear both have the same amount of teeth (71). The notches that you are asking ARE on the 3.94 ring gear.

The 3.55 ring gear is about 1/8-1/16 of an inch smaller than the one on the 3.94.

If you put them both side by side, you should be able to see which one is smaller.

Originally posted by barza21The notches that you are asking ARE on the 3.94 ring gear. The 3.55 ring gear is about 1/8-1/16 of an inch smaller than the one on the 3.94.

are you talking about width of the gear, or height? i'm assuming width (left to right)

Yes, width.

I didn't measure it from end to end though. I measured it from the edge of the splines to where the differential is mating with the ring gear.

Don't know if that makes sense though... lol

as soon as i get the trannies in front of me again, i'll bump this. Thanks barz!

i just did a overhaul on my nvt350 and while i was working on the diff at school i found another nvt350. i used some spare parts that i needed than with out even meaning to i found out that it was a neon trans. lol. The diffs are not too noticeable but when u try putting the 2 wrong parts together, you will notice. lol thats what happend to me lol.

they look the same don't they.

figured i'd post some pics to tell the difference.

first pic: 3.55 differential ring gear splines
second pic: 3.94 differential ring gear splines (with hash ID markings)
third pic: 3.55 ring gear measurement (1/8" smaller)
fourth pic: 3.94 ring gear measurement (1/8" larger than 3.55)

thanks to barz for the measurement idea.

http://www.2gnt.com/?d=Differences_in_the_3.94

shazzaaammm

VERY GOOD INFO MIKEY!!! :thumbsup

I have used a 3.55 diff in a 3.94 .81 mtx before with good results. Will have to compare the 5 mtx's I have at home.

So can you really tell a difference between the 2 bottom end wise or top end wise? Or is the driveability about the same?

Originally posted by BurninThatVtechA
bottom end wise or top end wise

wtf r u talking about. elaborate on what you mean.

Originally posted by 420agreenvilleSC

Originally posted by BurninThatVtechA bottom end wise or top end wise

wtf r u talking about. elaborate on what you mean.

Mainly in third gear. Power everywhere else seemed the same for the mods. The gearing was quite noticable. A dohc neon with mopar computer has altered shift point like everyone knows. 1st 0mph - 40 ; 2nd 40mph - 58mph ; 3rd 60mph - 100mph ; and the rest is a mystery to me. With the 3.55 diff in an r/t mtx 2nd you can run to 62mph, and 3rd goes from 62mph to 113mph. Fun when messing with low powered boosted cars.