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Keep the th400, or go OD

As stated at the beginning, truck has a 205 in it currently that I will use no matter what
 
No I don't, just trying to get a judge by doing the rpm calcs.

Has anyone ever used or been in a 4x4 truck with a gear vendor's unit on the back of the tcase? Just wondering if anyone has any real world experience with them. The cost of them are really high (and the odds of finding one used to fit my application is going to be difficult I can already tell) but when I look at the cost of swapping a 4l80e (cost of case, maybe even a rebuild if higher miles, harness possible rework, redo crossmembers, shorten/lengthen front and rear shaft, ect) with one of those gear vendors it would be just bolt on to the back of the tcase and shorten the front portion of the rear shaft (2 piece shaft on the rear of my cc) and that is it. Sound nice....until I look at the cost again, haha. I guess if I could find a good 4l80e for a smokin deal then the overall cost of 4l80e swap would be less.

These sound really cool, just wondering if anyone has some experience with them.
 
The one drawback to a Gear Vendors OD on the rear output of the transfer case will be you can only use it while in 2wd..(which may not be a big deal,since its mostly intended to reduce highway rpms..)

There was a "Ranger" gear splitter OD that went between the tranny and engine,but were only for manual transmissions as far as I know..

I think your right about the 4L80E being the "cheaper" & easier way to get OD and if you look around,you may well be able to score a good one for say,500 bucks from a salvage yard...
 
An added bonus of the 4L80E over the 400 also is its longer, helping alleviate some pain the front shaft causes that we all have seen before.
 
454Sub said:
An added bonus of the 4L80E over the 400 also is its longer, helping alleviate some pain the front shaft causes that we all have seen before.
Click to expand...

Actaully being longer causes more problems to deal with. As stated at the beginning, this will be a dedicated two rig. Don't really care about the angle of the front driveshaft. So since it's longer that means dealing with lengthening/shortening front and rear shafts, modifying crossmembers, and also figuring out the shifter linkage (have seen some who say the shift linkage in the 4l80e is in the same location as the th400, but have also found some who say they are different....could be generational which means would have to wait and see what case you could get to see if this would be an issue).
 
diesel4me said:
The one drawback to a Gear Vendors OD on the rear output of the transfer case will be you can only use it while in 2wd..(which may not be a big deal,since its mostly intended to reduce highway rpms..)

There was a "Ranger" gear splitter OD that went between the tranny and engine,but were only for manual transmissions as far as I know..

I think your right about the 4L80E being the "cheaper" & easier way to get OD and if you look around,you may well be able to score a good one for say,500 bucks from a salvage yard...
Click to expand...

Yeah, I have thought about that, and the fact that you can't use the OD while in 4wd isn't that big of a deal as what I am really worried about is like what you said, reducing rpm's at highway speed.

The other issue of finding a seperate 8.1 with it's own harness along with finding a seperate 4l80e with it's own harness....is I am not sure if you can have both harness's combined and reworked to work together with the 8.1 ecm, or if you would have to keep each harness/ecm stand alone (meaning a stand alone for the motor and a stand alone for the tranny). Anybody have any insites on this? I guess the best thing would be to find an 8.1 with a 4l80e/4l85e mated to it and buy the whole thing huh? :) But that is harder than you would think, haha
 
Had a buddy with a gear vendors OD in a motor home and we towed a boat with it all the time, that's partially why I proposed the idea in the other thread.
 
I have had a gear vendor in my suburban for about 10k miles (454 4spd and 3.73 gears 33 inch tires). I have been really happy with it, splitting gears while towing is nice too. They are a neat OD, but if you research, they are not the bullet proof piece they are made out to be. I dont think I have pulled 10k with the burb since I added the gear vendor, but have towed 8k, and holding OD at 65 was no problem.
 
How about this for a new thought....what about swapping in an NV4500??? Good low first for towing with the OD. Pretty stout manual tranny from my research. According to what I have read as well, I should have the round 6 bolt pattern np205 32 spline input currently on my truck (truck is still at my bro's house in WA, so can't go look), so with a ~$200 adapter from advanced adapters my 205 should bolt right up to it. I will have to move the crossmember as the 4500 is obviously shorter in lenght then the th400 (I think...) and also figure out something for the tcase shifter (not that big of a deal), I would think I could get everything to swap to a manual tranny (pedel assembly, slave/resivoir, bellhousing, tranny, linkages, clutch, ect) for at least the same amount, maybe a little bit more than the price of getting a 4l80e in there. What say ya'll?
 
Surprised nobody mentioned the option of using the 205 behind a 4L80E as if this was your plan be prepared to look for that rare one-year-only '91 adaptor with the same year rare shifter, too. Then you'd have to do some machine work to spot face the rear output shaft housing on the 205 to get the fitting for the spend sensor plug to screw in. Also to look for the speed sensor gear itself, too. A lot of work to make it compatible to use as VSS goes.

I'd use a 241 t-case for simplicities sake as the years are spread out more than just '91. It will be much cheaper, too, in the long run. Those '91 adaptors for the 205's just are not cheap.
 
I converted my 205 over to a VSS with a drill press, 4.5in grinder and about 2 hrs of time. All you have to do is find a 241 reluctor wheel, slightly shave it down till its the same size (about 1/8in) as the factory 205 plastic worm gear and switch them out. Drill the 205 housing wherever you see fit in the rough center of your reluctor wheel, face it down with your grinder until a standard oil dipstick barely squeezes between the sensor tip and the highest tooth of the reluctor wheel, using it basically as a feeler gauge. Its a pretty simple job really. The adapter and shifter are going to be your bigger problems.
 
I have a gear vendor in my crew cab, 454 th400 205 37s 456s and it would drop my rpms about 300-350 rpms. I talked to the main tech guy at gv and told him I wanted to put a cummins in front of it and he said it would hold up no problem as long as I wasn't building a high horsepower setup.
 
That is good to hear that the people who do have the gear vendors seem to like it, but I have been doing more and more research on these NV4500's and think it would be an awesome set up, especially with an 8.1 liter with after a tune I would hope would be close to 400hp/500lbs at the flywheel.
 
Yeah I do like it. It uses a switch on the floor like a hi/lo switch to turn it off and on and a manual/auto switch on the dash. When you flip it to manual it takes a second to actually shift so don't expect it to be super fast otherwise its always in auto. I think the nv4500 is a great combo that's what I plan on running with the cummins and the gv mounted on my 205. As for people being worried about it not working in 4x4 why would you need to have od in 4x4 that seems dangerous if you need 4x4 you probably would be fine without it lol. Also it uses mainly all th400 parts for internals I've had to replace a couple seals due to leaks and they're easily obtained from any trans shop
 
I don't think the worry is that you need OD when in 4WD (at least it wouldn't be for me). It would be if you inadvertently left the GV unit on and it went into OD while you were moving, which I assume would break things in immediate order.

Probably more a concern with the GV behind an automatic, as you know when the GV gets left on and you drop under 25MPH with the manual.
 
Mine kicks out under a certain speed in auto. Also it kicks the gv off when you move the tcase out of 2wd so no worries there
 
Huh. Dad's GV didn't have that feature for 4WD, a lock out would eliminate the potential, however slight the probability of an issue would be. The manual kicks out under 25MPH too, but because there is nothing to dampen the shift (I think that's called overrun in an auto), it was fairly brutal when the GV dropped out of OD with the trans in gear.

IIRC the manual specifically stated to avoid it doing that. Knowing what I know now, I wouldn't have been in OD as often as I was when I drove it. Lowest RPM's possible doesn't equal best MPG.
 
I never really used the manual function honestly never had the need it always pulled good or I had it off and very good point it is a very firm shift much like a trans with an aggressive shift kit you should definitely be aware of that. And the setup for killing it is a home brewed setup that works well. So if you look at the top of the 205 there's 2 plugs with springs for the detent. Mine has a sensor in 1 that uses one of the spots for the 4x4 light well its also what shuts off the gv computer I'll take a couple pics here in a minute
 
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