Transmission Choices

[drom68]

Here it is, I have a choice of transmissions and transfer cases that I can put into my 1981 J10. The J10 will be pure off road, but not a dedicated rock crawler or mud bogger, just an all around capable truck to have fun in.

Engine: I6, Keeping the 6 banger
Axles: Front D-44 OX Locker, Rear AMC 20 Detroit 4.56:1, keeping the current set up.
Tires: 36" TSL
Transmission Choices:
- Stock T-176/77/78- Which one is it??? and NP208- Ok trans, horrible 1st gear ratio and good/great transfer case with a good low range. All ready in the truck
- Ford T18 with granny low and NP 205- Great transmisison, great transfer case but poor low range
- NP435 with Dana 20 (early Ford Bronco) Great low range Trans and good transfer case with good low range.

Given the transmission/transfer case options feel free to mix and match for a recommended solution. Would also like to hear your reasoning.

[Serious Johnson]

Are those choices based on what you have available? How about a Jeep T-18a/208? That setup in my Wagoneer is very nice off-road, pretty good on-road, and truly sucks for towing due to the wide ratios.

S.J.

[drom68]

Yes, the choices are based what on I have on hand. Don't want to keep the T176, but ok with the 208. All three sets are in great condition.

[Cecil14]

I believe you could probably throw the NP208 behind the Ford T-18? You may need a different input shaft but I'm pretty sure that could work. That would be my first choice of those options. The NP208 may not be quite as stout as the 205, but it will be a whole lot quieter plus has a far better low range.


aa

[backroadin']

I vote for the NP435 and bronco D20 - good 1st gear AND good lowrange.
Second would be the t18/205. Pretty stout and still a better crawl ratio than the t176/208, although for the street, the 176 is the best driving tranny of the 3 since all 4 gears are useable....... but you're not using it for the street.

[Heavy_Metal_Thunder_81]

why not put the d20 behind the t-18 like what the 70s model FSJs came with???

[threepiece188]

Are those choices based on what you have available? How about a Jeep T-18a/208? That setup in my Wagoneer is very nice off-road, pretty good on-road, and truly sucks for towing due to the wide ratios.

S.J.
I really like my T18 for towing. I have the I6 as well and tow heavy loads regularly. Maneuvering around the yard, especially in reverse and even taking off up hill with a fully loaded trailer is so much easier. It is sure to prolong my clutch life too.
Dan

[mud89]

Don't you have to change the front axle if you replace the NP208 by a DANA20 ?

IIRC NP208 works with a driver side drop for the front axle and its differential, and the DANA20 with a passenger side drop ?

[Cecil14]

why not put the d20 behind the t-18 like what the 70s model FSJs came with???

Because he's working with a Ford D20. IIRC the Ford version has a different mount/input setup than the Jeep version.

The Ford version is also driver's drop, so no, he will not need to switch front axles to use it.


aa

[mud89]

Thanks, i still have to learn ;)

[drom68]

I vote for the NP435 and bronco D20 - good 1st gear AND good lowrange.
Second would be the t18/205. Pretty stout and still a better crawl ratio than the t176/208, although for the street, the 176 is the best driving tranny of the 3 since all 4 gears are useable....... but you're not using it for the street.



I was thinking the same thing, I really like the NP435/D20 set up. Just wanted to make sure I was not overlooking anything.

The stock T176/208 is not a bad thing, just messin around I can get all four tires leave a mark in 1st/low range. The transfer case is what makes the difference. I question the strength, but I try to use more technique than the skinny peddle on the right now-a-days.

The T18/D20 combo is a great idea, just need to get an adapter for this combo.

[Cecil14]

The NP208 is one of the strongest cases you have listed. By far stronger than the D20, there.


aa

[cajun_lad]

The NP208 is one of the strongest cases you have listed. By far stronger than the D20, there.


aa

:rolleyes:
208: aluminum case, chain driven, non twin-stickable
d20: cast case, gear driven, twin-stickable, and TeraLow makes a 3.15:1 kit for the 20

Care to rethink your original post?

[Cecil14]

NP208: 1 ton+ t-case.

D20: 1/2 ton at best t-case.

No, I do not care to rethink my post. Care to redo your research? ;)

Twin stick is great, and extremely overrated unless it's a dedicated rig that needs it. I've had my t-case twin sticked for a very long time and haven't used it once.

Not to mention the noise the ancient gear drive cases make. Show me a t-case today in a modern truck that's gear drive.


aa

[drom68]

NP208: 1 ton+ t-case.

D20: 1/2 ton at best t-case.

No, I do not care to rethink my post. Care to redo your research? ;)

Twin stick is great, and extremely overrated unless it's a dedicated rig that needs it. I've had my t-case twin sticked for a very long time and haven't used it once.

Not to mention the noise the ancient gear drive cases make. Show me a t-case today in a modern truck that's gear drive.


aa




Not to get into too much of an argument, but:
Ref Novak: Strength
"We are often asked our opinions about the strength of the Dana 20. The reader should be aware that these were the transfer cases that were found in the Jeep J4000 one-ton truck, where they perform most admirably. A Model 20 that breaks is usually due to a worn intermediate shaft and bearings, other worn bearings, or from the shock force resulting from an unskilled driver panicking his way through a rock patch. We've yet to see a broken Dana 20 transfer case in our own service, and we find them to be a most outstanding gearbox.
It is nearly remarkable how much power this compact transfer case can transmit and sustain. It is not so rare to see them handling Big Block grade power and deep, compound gearing"


D44 axles are is used in 3/4 ton trucks, doesn't mean they are the best solution......

Cost and weight are some of the reasons for a chain driven aluminum transfer case. Like anything, when maintained they are great solutions.

[Cecil14]

Absolutely. Given a choice I'd take the NP208 I gave away 8 years ago back in a heartbeat. I drive my truck all the time on the road and would give up the D20/300 cases with no questions asked. There are plenty of strong/stronger options out there for the same or less cost. The old Dana cases were good in their day but as with everything else technology is moving ahead now.

I've seen a TON of grenaded D20s through the years posted on here. AA makes a couple upgrade parts for them, I believe. The D300 is better yet, with way more upgrade parts available, but at an extreme cost.

The newer cases are aluminum/chain because of weight, like you said. It is also due to serviceability, noise, strength, cost, etc. There are a lot of reasons they've gone that route. Seeing the entire industry go that way says something to me.


aa

[fulsizjeep]

208 :thumbsup:

D20, not so much...

It IS personal preference, so I don't need to justify my thoughts. ;)

[duncanstives]

Wow... I was thinking the np205 was the same 2.6:1 ratio low range as a 208 so I looked it up since everyone here was saying the 208 would be better... 1.96:1 is pretty poor!

I my vote goes for the Bronco gear or the Ford tranny with the np208 if it will in fact bolt up and you want an easier time with the range shifter (you would presumably have to fab one up for use with the Bronco gear).

[drom68]

208 :thumbsup:

D20, not so much...

It IS personal preference, so I don't need to justify my thoughts. ;)


May not need to justify your thoughts, but it would definately assist me in making a decision....:thumbsup: Kind of like a parent telling a kid "because I said so...:banghead: " Just don't learn off that, makes me want to go agianst the grain :D

[drom68]

Wow... I was thinking the np205 was the same 2.6:1 ratio low range as a 208 so I looked it up since everyone here was saying the 208 would be better... 1.96:1 is pretty poor!

I my vote goes for the Bronco gear or the Ford tranny with the np208 if it will in fact bolt up and you want an easier time with the range shifter (you would presumably have to fab one up for use with the Bronco gear).


I like the NP435 with its very low 6.68:1 first gear ratio! Also like the 208 2.6:1 and the fact that it is the stock T/C. But I am also a fan of the D20 for some reason.

[cajun_lad]

I like the NP435 with its very low 6.68:1 first gear ratio! Also like the 208 2.6:1 and the fact that it is the stock T/C. But I am also a fan of the D20 for some reason.
I got my numbers here, based on you saying you had the granny low 435, http://www.grimmjeeper.com/gears.html

np435/d20 in 1st gear and low range w/ 36" tires:
61.93:1 drive ratio

t176/np208 in 1st gear and low range w/ 36" tires:
41.89:1 drive ratio

Sure, gear driven cases are noisy. But what isn't noisy about a 20+ year old rig, on tall tires?
I currently run a 208 in my wag for the only reason that it was a bolt in replacement for the 229, and I wanted to ditch vacuum operated 4wd.
I traded my QT for the d20 in my 78 cherokee for the strength and reliability factor. Chains stretch over time, gears don't, period. All are good cases, and with the right amount of attention will last longer than the vehicle most likely. It's just a matter of how much attention you want to have to pay, and how much work/money are you willing to do/spend to make a particular setup work.

[Cecil14]

Chains do stretch. Gears wear as well, as do the shafts they run on. The chain in the NP208 turns only when in 4wd. The gears in a D20 turn anytime you're moving. I think wear at that point is pretty moot. Not to mention chains are a lot cheaper/easier to replace than gears.

The low range in the stock Jeep D20 is 2.01:1. The Bronco D20 is 2.46:1, but is going to be pretty expensive to swap onto anything that wasn't meant to run it. Not impossible, just expensive. You can also take a mix of different gears and put the 2.46:1 stock low gears in the Jeep D20. This closes the low range gap between the D20 and NP208 quite a bit.

As mentioned this is going to be a lot based on personal preference. I drive my truck on the road a LOT and noise is a VERY BIG deal to me. I insulated the crap out of my cab and have done a lot to reduce noise.

I've also run a T-177/T-5/T-18/NV3550, in that order. I hated the T-18 with a passion. Yes, it is incredibly strong. Nothing I could ever do would have killed that, the D20 or D44s would have gone long before the T-18. But driving that thing sucked big time, even excluding the lack of OD. It was just annoying to shift, loud, had terrible gearing for everyday driving, etc. It's a dump truck trans, don't kid yourself. :)

For a purpose built rig it will serve you well. Again...this decision depends entirely on what YOU want out of your rig.


aa

[drom68]

The low range in the stock Jeep D20 is 2.01:1. The Bronco D20 is 2.46:1, but is going to be pretty expensive to swap onto anything that wasn't meant to run it. Not impossible, just expensive. You can also take a mix of different gears and put the 2.46:1 stock low gears in the Jeep D20. This closes the low range gap between the D20 and NP208 quite a bit.

As mentioned this is going to be a lot based on personal preference. I drive my truck on the road a LOT and noise is a VERY BIG deal to me. I insulated the crap out of my cab and have done a lot to reduce noise.
aa


The NP435 with D20 came from a early Bronco that is already set up and just needs an install. Nothing expensive about it, it is a driver drop that matches up with my driver side D44.

The T18 with NP205 is mated as well, it is a driver side drop as well. I can mate the T18 with the 208 with no money involved. The NP435 is a little different as I would need to get an adapter to mount them together.

This is not a daily driver. So a little noise is not an issue.

[zachandandy]

This is the only thread I've ever seen chain driven t-cases called stronger than gear driven. Also note this is in general discussion, not the off road section. If a chain driven case were somehow superior for an offroad only rig like the OP posted, I would imagine at least 1 of the aftermarket t-case manufacturers would build one. Comparison between gear strength and chain strength is not even close, and look at the # of moving parts to wear out. Anyone build a chain drive doubler? No. Anyone run 4,5, or 6 to 1 reduction(let alone 10 to 1 atlas 4 speed)through a chain? If they do not for long. As far as noise, fuel efficiency, and weight run a chain driven t-case inyour prius. These are fsj's they are loud, heavy, and far from fuel efficient, and that is why I love mine.

[Cecil14]

Once again I will state every single t-case I've seen in a modern vehicle is chain driven. If gear driven is 100%, hands down, no questions asked, better...that wouldn't be the case. And yes...there are plenty of 4:1 chain cases. Jeep Rubicon anyone?

All the huge diesel trucks from the big three use chain cases, have for a long time now. Those trucks build 1000lb. ft. of torque with little hassle. Can't say I've seen too many broken t-cases there, always other parts like axles and drive shafts.

And yes...I've seen a TON of chain drive based doublers. Lots of the YJ/TJ crowd use an NP203 range box on NP231 cases. No problems at all.

If you want your eardrums to bleed while you drive, go to town. But I'm certainly past that point in my adolescence. lol


aa

[cajun_lad]

Once again I will state every single t-case I've seen in a modern vehicle is chain driven. If gear driven is 100%, hands down, no questions asked, better...that wouldn't be the case.

Key word there is modern vehicle. EPA regulations, luxury style and comfort call for chain b/c they are quiet, light weight, fuel efficient, whatever. Since when has any car manufacturer used the "better" option? Next I suppose you are going to tell us to ditch that SFA, and go IFS, b/c most modern 4x4's have it. You're logic is flawed.

[cajun_lad]

And yes...I've seen a TON of chain drive based doublers. Lots of the YJ/TJ crowd use an NP203 range box on NP231 cases. No problems at all.

Huge weight difference btwn an FSJ and a YJ/TJ.

[Cecil14]

My logic is hardly flawed. Yours is simply extremely narrow sighted. ;)

If you still don't believe chain cases are up to par take a look at military humvees. How many of those have you seen with gear cases? Not a single one. Some of those weigh around 10k+ lbs. I know guys that drive them and they aren't afraid to beat the living tar out of them. Yet to hear of one breaking.

Weight's got nothing to do with it. They use the NP231s because that's what is already there.

I'm done arguing with you. Run what you like, I've provided the facts regarding chain cases.


aa

[zachandandy]

Next you'll tell us timing belts are stronger than timing chains, and plastic is a stronger material for bumpers and such than steel. Modern vehicles are built solely for profit magins. Nobody builds anything like an fsj anymore. I mention 4,5,6,and 10 to 1 and you point out baby jeeps have 4 to 1. These are fsj's, the op is offroad only, and gears are stronger than chains. If you want a smooth, quite, fuel efficient ride, there are plenty of escalades for sale at repo auctions.

[Cecil14]

Guys. Take a look at your facts before you start spitting out worthless facts. The case in the Rubicon is rated for WAY more input torque (at any given weight) than any t-case ever run in an FSJ. Now stop talking before this turns into Pirate. Your cases have been stated. The OP can make his decision based on the information here.


aa

[cajun_lad]

(Hands cecil a tissue)

Here's the only fact that you need worry about...
Drivetrain selection is always going to be opinion based.

[cajun_lad]

If you still don't believe chain cases are up to par take a look at military humvees. How many of those have you seen with chain cases? Not a single one.

:rolleyes:
I've never looked under a Humvee, so I don't know what they run. I can imagine that it wasn't the best option, but the lowest bidder on the gov't contract. That's neither here, nor there. But according to your post, you just argued against yourself?!?!?

[fulsizjeep]

makes me want to go agianst the grain :Dbe my guest, I've made my choice ;)

[Cecil14]

I've never looked under a Humvee

Obvious in more ways than one. The case was built by BorgWarner and is extremely stout, regardless of your ignorance.

But according to your post, you just argued against yourself?!?!?

Fixed my mistype, just for you Princess. My point was, and still is, quite clear as well as correct.


aa

[zachandandy]

Everyone quick, name the strongest t-case on the market, run by 90% of rock crawlers and rock racers. Now imagine if they new what Cecil does. How much better would that atlas3 chain drive be?

[Dr.E]

(To the rescue with a large bucket of cold water)
The best answer is to agree to disagree!
There are folks that can break any T-case that is on the market.
Some like the bragging rights of destroying the indestructible.
Some of us like the challenge of mastering the driving skills to push our components to the limit without breaking.
Which ever really doesn't matter...I find both styles entertaining.

[cajun_lad]

This has gotten way off topic and turned into a flame war. I guess sarcasm doesn't come out very clearly in text. My main point was that aluminum vs. cast cases and chain vs. gear driven cases are merely a matter of opinion on which is better. And don't use "b/c such-and-such uses them, they have to be good" as a reason to support your opinion. Especially when such-and-such happens to be the gov't. They do not use top quality parts. They use readily available and easy to change out parts.

[Tad]

I'd really appreciate this staying on track and even cleaned up a bit so that it maintains some value.
Thanks,
Tad