mudracer said:
1. A transmission reaches lockup when the convertor locks up. If you are running a huge stall, maybe you should change convertors for more efficiency.
2. I dont deny that the TH400 has an inefficient rating. In Pro Stock, if you were using a th400, you would want to change due to the inefficiency. In a stock vehicle, you cant detect it.
3. if you think for a minute that your quadratrac transfer case doesnt waste inertia by spinning ALL of the axleshafts ALL the time, youre sadly mistaken... thats called parasitic drag. Do you remember the ageold NP203 transfer case? Full time, its a pos. you get about 8mpg with it. install an NP205, and your mileage doubles. why? parasitic drag. hmmm wonder why they call it a FULL TIME case.... kinda like the quadratrac, eh?
I do have a lot to learn. I am not, however, stupid.
The NP208 is a completely different animal than the quadratrac. its a part time case. please dont compare apples and oranges.
whatever you do, DO NOT switch to a 700r4. (That is, unless you know a tranny guy that LIKES you, and you enjoy tranny swaps) If you were to do some shopping around you would find QUICKLY that a rebuilt th400 with ALL the bells and whistles runs around 12-1600 bucks. a 700r4 starts at 1600, and goes UP from there. and its not even dependable. Sure it has less parasitic drag. why? the parts are lighter, less dependable, weaker, and inferior in almost every way.
its your money. you can spend it where you want.
oh, by the way, my tow vehicle has a 500 caddy, and a th400.
my race truck has a big block chevy, and a th400...
my buddies run them, abuse them, and they keep ticking.
If you didnt know already, im a chevy guy.
(edit!: Im so so sorry, jim... I forgot to ask you.... when did they start putting overdrive in a transfer case? I know of the Warn Saturn Overdrive.... but no modern case has an overdrive in it. Unless of course, you would like to educate me on that, too.)
1: The converter engages at the stall point but the 17% or so slippage doesn't go away magically. Why do you think they have lockup converters now?
The Jeep TH400 has a high stall from the factory. If I was going to $pend the $$ on replacing it (About $200 for a good one or $79 for the cheapie reman) then I miteaswell rebuild the trans (it doesn't engage first gear unless I manually engage it, which means the sprague is shot and no matter how I adjust the modulator, it up shifts to drive too soon unless manually shifted. That and it has a shady history of service life) I'd also have to $pend for adapters and output shafts (I had the correct adapter that I sold on EBay for $200 but I didn't have the right output shaft to make it happen)
Simply put, my beat-to-**** '73 J4000 doesn't have enough value to put thou$and$ into fixing up (I have an '84 J10 for that and I have spent too close to $10K on that in parts, storage, time and machine work and it's STILL not all in the same location! I even bought a cabin near Reiter and built a garage to work on it in but haven't had time to getaroundtuit in the past year!)
2: In a stock vehicle that is driven in town all the time, no you won't notice much, but take it out on the freeway and listen to how much the engine whines w/o an O/D with good pulling gears. The 727 has slightly better gearing for takeoff (TH400 makes up for it with the stall slippage) and I can get even better ones for @$100 for the 727 (same as 999)
3: A converted quadratrac DOESN'T turn everything all the time. In fact, except for the case, it's hardly a QT anymore. It essentially becomes a NP208 with parts out of place. The power goes in through the input shaft (and to the low range or high range driver depending on the position of the seperate shifter. Mine is even dash mounted with a PTO cable!) to the drive chain.
Drive chain runs to the output shaft (rear is always engaged because this is a part time converted rig) which has a sliding fork to engage/ disengage the front axle drive (I also have locking hubs so my front driveshaft and axles don't turn unless either the tcase is engaged or both hubs are engaged) In my case, with the Milemarker O/D kit (It's also a Milemarker PT kit) one of the gears that runs the chain (output shaft) is smaller than OEM, resulting in a 17% O/D. The thing I don't like is ALL the power has to pass through the chain before it gets to the wheels. The chain and overhaul kit is @$200 (I'm also tired of putting oil in it for each long trip just to keep the chain noise down)
While I am not a Chevy hater, I have killed MANY SBCs (17 in one season by different builders from 265 up to 383 stroker and 400), one BBC (396 in a '66 Grande Parisienne) and SBFs (only 6 so far), BBFs (360, 390, 460 and the one that got away was a 428 sideoiler) and the occaisional Mopar (273, 318, 360, 340 with a rod out the side, 361, 383, 440, 413) and so far 1 AMC 304 V8 (that was knocking when I got it. I still drove it 3 months after the rod knocked a hole in the side)
I was just as hard on Japanese cars (no time to list all I killed, fixed and killed again) but it seems inline 6 cyls and I get along. I haven't killed the 304 in this beast yet (it came out of a '77 AMX I bought for $200)
The reason I have for swapping to a 727 is this: I have a good one I got cheap that I went through and it's fine. I know the tricks to beefing them up w/o having to rebuild them totally. Same goes with the NP208 tcase. I have had good luck with them. I found mine to be great for trailering when you can shift to low range for takeoff on a hill, get up to 10-15 mph and pop the trans to neutral, upshift the tcase and drop the trans back to first and go.
Until @'99 I used to go to swap meets with a trailer made out of an IH bus (weighed almost 5 tons empty) behind my '83 Cherokee with Mexican 4.5L, (which is almost identical to the stroker 6 I'm building except I'll be getting twice the torque with LPG and better head/intake/exhaust/cam) lockup 999 auto, NP208 and 2.72 gearing with LT235/75R/15. Anyone who went to my old place in Skyway can tell you what the hills are like getting to it. It's even more fun in rush hour traffic and having to take off from a standstill multiple times before reaching the stop sign at the top!
I have friends in the trans biz that can build me a 700R4 for @$800 (on the bench) that has the upgrades needed for towing etc. I'd sooner go to a 4L80E but the external stand alone trans controllers don't work worth a damn. On the bright side, I would use one to run on an AMC motor with GM TBI setup pretty easy.
PS: BBCs can be finicky too! I used my '87 MJ with 230,000 mile 4.0L (with pukeout 5 speed, 3.73 gears and 33" tires with no low range) to pull a full size Chev with big block (it died in the middle of a traffic light) along with the car trailer and full sized Blazer on the back up a slight grade and almost 3 blocks into the NAPA parking lot in Totem Lake (have pics and witnesses to back it up) so I do know where the torque lays! (and I didn't even fry out my 80,000 mile clutch!)
Just for good measure: I was a trans tech for 5 years (mostly Mopar cop cars and taxis till they faded away) so I do know a little about what I'm talking about. (I'd still be a mechanic too if it wasn't for the %$#^@&*( green Honda that fell on my head during the Duvall quake of '95!)
