D20 maintenance

[ColeTrickle]

Hey guys, I'm wondering what the maintenance on these t-cases are. As some of you may know I recently became the owner of a J20 w/ a leaking D20.

I have done much research on this case and have read numerous posts on the case. I have also searched the archives on the home page.

Here are some questions,
1) What fluid does everyone recommend? SAE 80/90?
2) I have heard some tech articles to increase the low range of this case. For example TeraLow. Would anyone happen to have links or write ups on install?
3) How hard are these cases to work on? Simple in design? I'm limited to tools...sooo.
4) Is the shifter supposed to be loose and full of play? It's attached and goes into gear but it seems to be held into place with zip ties.

Thanks everyone for all the help, advice and knowledge.

[Stuka]

I run 85w90 with 1 pint of STP oil treatment in it.

They arent to difficult to work on. If you have ever rebuilt a manual transmission you could rebuild a D20.

The shifter should not wigglle lall over. Mine goes in pretty firm and stays pretty tight, never had it pop out of gear or anything.

[Crazy_Jeepman]

I drive them till they drop.......If they ever do, then put in another. They are Cheap and lots of them around. I would never put a lot of $$$$ into one. They are Tough, keep it full of gear oil and forget it.

[Lindel]

If it leaks, you can get a new seal kit at www.collinsbrosjeep.com, (http://www.collinsbrosjeep.com,) if www.bjsoffroad.com (http://www.bjsoffroad.com) doesn't have one.

[ColeTrickle]

Thanks for the replies guys.
I've read that the teraLow requires abit of work. Probably more than I could handle. Something like specific early Bronco Dana 18 parts. There's a few threads on the subject...just not a step by step procedure. I was hoping to get a better crawl ratio out of it since this will be my custom wheelin' rig.
I have also compiled a list from BJ's...that place is like looking at the Holiday Wish List catalog.

Thanks for the suggestions, help and advice.

[Stuka]

The mods include grinding part of the case fo clearance. As the low range gear is larger.

[ColeTrickle]

Stuka...Nice website. Have you looked into your T-case identification lately? I recall that you had 2.46 marked on the case...whereas most cases were 2.03:1. Any news?
Having a QT in the '79 with 2.57:1 gear ratio, leaves me to feel somewhat dissappointed in the D20. What's your perspective?

Thanks.

[Stuka]

I havent pulled the case apart... was going to. But the gears didnnt show any where when I pulled the pan. And I totally forgot to count teeth while I was under there :(

Depending on how hard you are going to be wheeling it...you might just want to put a part time kit in the QT, and put some manual hubs up front. So you can have 2wd and 4wd. The only downside to the D20 with the TH400 is the adapter plate is aluminum and brone to breaking under hard wheeling. Although larry miller from here on the forum is considering making a steel adapter plate. Which would make the D20 a nice case to use with the TH400.

For low range, you can either use 2.46 gears from a bronco, or the terra low gears, although they are kinda high priced.

EDIT: oops...just realized the 79 you spoke of was a J10, not the new-to-you J20. In which case forget the bit about just making it a part time tongue.gif If its just the pann gasket thats leaking I would do it...very simple and fast. Or you can go through a full rebuild and just find a set of bronco gears like stated above, or just keep the D20. Not sure if you said...but does it have a 4sp or a 3sp tranny? If it has a T18a the 2:1 low range should be plenty with the 6.32:1 1st of the T18a.

EDIT PART II: ok..another edit smile.gif I should really look before posting hehe. Your sig says a 74 J20 with a TH400/D20. Didnt know they came with a D20 behind a auto in 74...unless it was put there. In which case the 2:1 low isnt all that great for a automatic. So you may want to look for those gears. Ok...done editing for now smile.gif

[ November 10, 2002, 06:45 PM: Message edited by: Stuka ]

[ColeTrickle]

Well, I have an edit too! I NOW see that you have a T18a, so your already set up to have a awesome gear ratio.
:cool:
I'm gonna look into those gears. This is gonna be my primary hardcore off-road rig.

The '79's just to nice to beat all to heck. And yes the '79 does have the PT conversion.

Thanks again for the insight.

[FSJeeper]

If you go with the low gear kit in the Dana 20 and do not uppgrade the ouput shafts to 32 spline, you are going to break. Period. Especially if you lean on the engine and lift and go bigger tires.

The Dana 20 is barely adequate for a stock FSJ. Change to a low gear kit like a 4 to 1 and you multiply the torque by 4. You will break if you really use it.

[Stuka]

The 32 spline output can be gotten from a bronco D20 as well.

[ColeTrickle]

Would ya'll recommend the D20 for some rough wheelin' or ????? Am I chasing my tail with this one? I'm gonna run this one till it breaks. Should I keep my eye out for the Bronco gears/shafts or another entirely different case?

Again thanks.

[Stuka]

depends what ya consider ruff. If your talking 38's and lockers front and rear with lots of wheell spin on rocks...go to a 205.

or..you could just pickup D20's as you find em...they are cheap...LOTS of them out there...and easy to fix/swap in.

Scotty has been running his D18 for a while but broke it..so is going to a D20. He runs 38's and is pretty ruff on his rig.

But I wont start the D20 argument again with FSJeeper smile.gif

[ColeTrickle]

Thanks again Stuka...hope I didn't bring out old quarrels :rolleyes: .
I'm sure I'll have to find that thread though :D .
I'll just run it till I break it.

Appreciate it.

[scotty]

Originally posted by Stuka:
depends what ya consider ruff. If your talking 38's and lockers front and rear with lots of wheell spin on rocks...go to a 205.

or..you could just pickup D20's as you find em...they are cheap...LOTS of them out there...and easy to fix/swap in.

Scotty has been running his D18 for a while but broke it..so is going to a D20. He runs 38's and is pretty ruff on his rig.

But I wont start the D20 argument again with FSJeeper smile.gif LOL,yes we arent going to go there again smile.gif cole trickle,it was not a quarrel,simply a good natured debate. i like FSJeeper. he is very knowledgeable and and is building one heckuva rig. hmmm i forget what that thread was called...

it depends alot on your wheeling style. my spicer 18 did not give me any trouble at all when i had still had a 44 rear and was alot more careful with it. if you are slow and deliberate you will prolly not have any prollems out of a d20.

hoowever,the 14 bolt has given me lots more confidence that maybe it shouldnt tongue.gif as i am not afraid anymore to push it just as hard as i need to in order to follow someone up a hill or over an obstacle. the days of only trying something twice before going the easier route are over.

here in ohio we have our share of rain :mad: and thus the trails can sometimes be pretty slick. lots of the holes and hills require a fair amout of momentum,throttle and wheel spinning to get thru/up. what i have found is that the spicer 18 does not hold up well to the sudden shockloads of bouncing up slippery,rutted hills in a full throttle 2nd gear attack.

dont get me wrong,i dont beat on it if i dont have to,but when you drive the same traisl over and over you start looking for new lines and new ways to attack things.

despite FSJeepers reccomendations i am going to give the d20 a shot without regard to possible tailsahft breakage ;) i will not spend a rediculous amt of $$ on the tailshaft conversion if that is actually what i break. i am guessing i am going to also break the gears,since they are simlar sized in the 18 and 20 and thats what i keep breaking. the 10 spline 18 shafts are for some reason holding up fine.

at any rate,if i continually break d20 gears or tailshafts,i have an sm465 and 205 downstairs to install. well see what happens smile.gif

also,just FYI,the bronco cases ive had had the same spline counts on the tailsahft as the d20. even if the sahft was bigger,it does not interchange with the jeep d20 shaft,and nor does the complete tailshaft housing. the bronco case is very different. pretty much the only thing you can swap is the upper slider,intermediate gear,and the 2 high range gears. the lower slider will work with some mods to the shift fork,but its much easier and better to use the lower slider from the spicer 18 so it works with the fork without modification.and the input gear. in most cases the bronco takes the same 18 8 23 input gear as the spicer 18,so it will swap onto 6 spline tailsahfts for a 2.46 conversion.

heres a link bout the 2.46 and 3.15 conversions:

http://www.jeeptech.com/convxfer/

its really simple conversion. disassemble,grind for clearance,reassemble with the appropriate gears.feel free to email me if you need some tips on d20 disassembly or have some other specific questions...

[ November 11, 2002, 05:56 AM: Message edited by: scotty ]

[ColeTrickle]

Appreciate it Scotty.
The type of trails your talking about seems abit like ours. The continued abuse time after time is also a concern. I think I'll just run it till it breaks then go from there.
I'm not up to swapping in a D20 everytime I break. I just like things to be bulletproof.
I'm pretty new to everything outside of a QT, hence the numerous questions. I do know that I'd like to have a lower than normal crawling gear in my transfer case. We'll see ;) . For what I'm thinking of doing...it's goin to cost some mulla, something I don't have right now.

For now though, to close my thread...I'm just going to get a gasket set to quit the leaks and refill it with gear oil.
...And run it like I stole it!

[Lindel]

I have a small hunch where you can get a spare D20, should you decide to mistreat yours :D

[scotty]

i do plan to mistreat mine :D if it breaks i have a spare allready,and i have numerous d20 internals from the various cases ive dismantled/rebuilt,etc.

ill carry a tailsahft housing,complete with yoke and ready to install with me.if i break both the scout d20 im installing,and my spare jeep d20,it will be time to upgrade to sm465/205. i hope it doesnt come down to that,cause i love my 258,but i will be very tempted to put a small block in front of it if i have to install the chevy tranny ;) tongue.gif

ill let you know how it goes after i pound on it a few times ;)