Dana 300 vs NP203

[FollowMyRuts]

I Currently have a Dana 300 out of the CJ5. I was looking at building up a TH350 and matting the Dana 300 to it. I have the chance to get, for free, a TH350 w/ NP203 Tcase. the tranny doesnt have Reverse and needs rebuilt but the NP203 Tcase works. should i a.) Keep the dana and buy the adapter for the TH350/Dana. b.) Keep the NP203 Tcase hopefully its a passangerside drop. c.) ive seen some people double up the NP203/Dana tcases. is that a good option too? i need some help on this folks, and you guys seem to know whats going on!! Thanks in advance!

[nick]

unless you are going to do a lot of stretchin 350 203 won't work. I run a th400 with 203/205 doubler and only have about a 20 inch rear drive shaft in a 110 inch wheel base cj7 But if possible I wouldnt use a 203 without a doubler check on the 300 adapter and figure out what trans and transfer will measure out Good LUck

[FollowMyRuts]

Well, we are stretching it 4 inchs on both ends, and the 203 doesn't look much bigger then the D300 if it is at all.I'd like to keep the D300 because they're strong but the Adapter's are about $500. Thanks for the reply!

[blazerbrad]

If it's a factory TH350/203 combo than it will be passenger side drop. The 203 only has a 2:1 low range and is a full-time case from the factory so no 2wd mode unless it's been converted (which was pretty common).

Personally I would prefer to go the 300 route.

Many people use the 203 range box that contains the 2:1 planetary for a doubler. A guy in our club has a TH350/203 range box/300 in his Samurai. It is stretched in the back but not an abnormal amount to fit, but it is supre tight. Based on that you could get it to work, but it's a lot more work and money for something that I'm not really sure you need.

[boomhauer]

just remember that the 203 is a chain driven pig. i always make a point to stay away from chain driven cases when it comes to offroad use. one broken tooth can/will ruin a good day in the woods !

[FollowMyRuts]

just remember that the 203 is a chain driven pig. i always make a point to stay away from chain driven cases when it comes to offroad use. one broken tooth can/will ruin a good day in the woods !

Thats kinda what i was thinking. but god thoughs adapters are friggin expensive! lol

[blazerbrad]

You are not going to break a 203 in a Jeep. The only issue I have ever seen is that after a lot of miles the chain gets worn and sloppy and starts slipping. Keep in mind these cases were designed to go into 3/4 and 1 ton trucks.

[FollowMyRuts]

well, he guy apparently doesnt have the transmission anymore, soo im back to square one, looking for a TH350 tranny to mate up my Dana300 or if i can find a TH350 with a t-case... anyways, thanks for the advise guys!!

[KargoMaster]

Better late than never....

203 vs. 300... ...BOTH!

Below is my NP435 trans with an NP203 (low range gearbox) in a Chevy variety, flipped upside down, with a 23 spl Dodge input gear in it... with Dana 300 bringing up the rear...

(T-150 looks sooooo small next to this)



By the way, if I had to do it over, I'd have bought a STaK... but the doubler should provide me with hours of shifting entertainment...

[gothodgie]

Better late than never....

203 vs. 300... ...BOTH!

Below is my NP435 trans with an NP203 (low range gearbox) in a Chevy variety, flipped upside down, with a 23 spl Dodge input gear in it... with Dana 300 bringing up the rear...

(T-150 looks sooooo small next to this)



By the way, if I had to do it over, I'd have bought a STaK... but the doubler should provide me with hours of shifting entertainment...

very nice setup... what is the 1st gear ratio on the np435 ?

[94Dodge Truggy]

203 is geared high. 300 is lower. with hp the 300 will need heavy duty outputs where the 203 is up to the task. Stak 3 speed is nice.

[KargoMaster]

very nice setup... what is the 1st gear ratio on the np435 ?

6.68 - 3.34 - 1.74 - 1.00 -- 8.26 reverse

And yes, I specifically went with 203 / 300 because the gears were different ratios (as opposed to the 203 / 205 which would certainly be stronger, but they have numerically identical gearing which limits gearing options)

203 = 1.98:1
300 = 2.62:1

I also did 32 spl outputs front and rear of the 300 just as Truggy said...

All told, I have less in my setup than a STaK, but far more to go wrong...
3-spd STaK is far better than "nice."


ps - I run 4.10 gears in difs... I like 4.10 gears... I choose to get increased torque through tcase(s)...

[KargoMaster]

Also, you may be interested in the fact that my NP435 is 2wd version...

only difference is the bolt holes for the rear output (but if I had a 4wd, I couldn't have flipped the 203 so easily):

[KargoMaster]

Last post just to clarify my setup...

To make all this possible, I needed to replace the mainshaft of the 435...

Top is new main shaft (23spl output, only about 2" stickout)
Middle is stock 2wd main shaft
Bottom is the 4wd main shaft (stock adapter/housing is like 9" long )