T-case Frustration Help me save my sanity

[coolguyinjeep]

Ok, im having a kinda bad day and am sick and trying to figure out my T-case dilema. I want to use my amc th400 but get rid of my 3 qt t-cases. I am considering either a dana 20, 300, or an np205. Its my understanding that I would have to buy an adapter for the 20 and 300 and change the tailshaft of my tranny for the np205. If any of this is wrong please tell me. So as far as cost, durabilty and quality, which would you suggest.
Thanks,
Mike

[Crazy_Jeepman]

Since you have a Q-trac, the only t-Case that will bolt to the TH400 that was in front of the Q-trac is another Q-trac. You will need adapters and tailshaft change no matter what T-case you wish to use.

[Gladi8r]

Since you already have the pass side drop why not just swap in a 727/300 combo?? No adapter needed

[coolguyinjeep]

Originally posted by Gladi8r:
Since you already have the pass side drop why not just swap in a 727/300 combo?? No adapter neededThats an option I guess. Is the 727 compatable with a cheavy 350 or 383? Whats the difference between the 727 and the th400 as far as strength and performance? oh and is the 727 a mopar tranny or chrysler?
Thanks,
Mike

[ October 28, 2002, 09:57 PM: Message edited by: coolguyinjeep ]

[dnixon]

I believe the guts of the 727 are the same as the Chrysler version BUT everything else is different regarding the case of it.. Mating surfaces, pans all of that is different for the AMC engine versions.. So no I don't think you will be able to fit it up to a chevy engine.. BUT i could be completely wrong this is just what i thought others had said... Good luck!

[coolguyinjeep]

OK, whats the differnce between the tf727 and the tf(8)727? So I would want to get a tf727 from a AMC then right and find out if it fits chevy?
Thanks again,
Mike

[Crazy_Jeepman]

TF727 will not bolt to a Chevy. You eill need a Chevy TH400 and adapters to what T-case you wish to run. You could look into the running gear of chevy as they ran Pass Drop front Diffs. TH700R4 NP208 I have in my Suburban would work. the TH700R4 is a OD trans. Several other Chevy drive train swaps would work great. I am unclear on this but it looks like you are thinking your TH400 will bolt up to the Chevy 383 you are building. It will not bolt up, in case you were thinking it will.

[Sundowner]

the th 4000 takes about 40 hp to operate, switching to a 7272 should offer a nice power boost ;)

[Bob Barry]

Only if you somehow managed to get your 727 to not suck up 40hp either. Any auto-tranny is a hp-robber, and the TH400/TF727/C6 trannies are all in the same ballpark. For what we use our trucks for, the extra reliability of the heavier-duty tranny is worth the hp penalty vs. any lighter-duty transmission. I could probably have 20hp more at the rear wheels if I swapped in a TH200... for about two blocks, before the tranny puked out its guts.

I was facing a similar dilemma, and came up with the following solution: I just picked up a TH400/NP205 combination out of a Chevy pickup, and am going to swap all the guts of the tranny over to my AMC-pattern TH400 housing. I just eyeballed the setup, and it looks like the rear output shaft yoke would sit right where the QT's reduction-unit ends, and the front output is about 2" lower and more centered, so the front driveshaft runs UNDERNEATH the corner of the TH400's oil-pan, rather than 1/8" to the right of it as it does with the QT. This will relieve the front driveline angle with the SOA that's going in at the same time.

The price of this powertrain combo varies from region to region; I picked mine up for $350 in runnable condition, but where there are serious mud-runners it may go for more.

BTW, you'll never realize how spindly the output yokes on a QT are until you have it side-by-side with an NP205. My first thought was "Oh, how cute! Look at the little-bitty baby output yokes..." :D

[ October 29, 2002, 08:53 AM: Message edited by: Bob Barry ]

[Sundowner]

I know, I was just kidding ;)
you got the 32 spline 205 set up?
sweet.
I bet you could fit a tcase doubler in there.. :D

[Bob Barry]

Ah; ok. No smiley+only 1 cup coffee=no perceive funny...

;)

I do have the 32-spline unit, but unfortunately it might be the long 32-spline input gear unit, which would have to be swapped out for the short 32-spline input gear. At least I wouldn't have to modify for the different bearing. A doubler is still a number of years away for me, though.

As for strength, though... I think the gears on this box are about as wide as the QT's drive-sprockets! Yet, the box is relatively compact; about as small as the QT, and smaller than my NP229. Certainly not LIGHTER, though, with that cast-iron case.

It's no wonder these things are so popular, despite the poor low-range ratio. I guess if you've got something powerful enough to break everything but an NP205, then the difference between a 2.75:1 and a 2:1 ratio is negligible.

[Sundowner]

I've given thought to a "redneck doubler"
whic would basically be a t-case in front that has the wrong side drop attached to the tranny, and a divorced t-case in back with the proper side drop, connected to the first t-case by a u-joint only, no shaft. unlimited clocking, no adapter, fun with fabrication making a x-member.