how to tell the difference between a t-18 and a t-18a

[Gwamp]

I have a t-18/D-20 combo that I am going to be selling and I am wanting to know which of hte T-18's I have. It is marked T18 1B on the case. Does this make it the closer ratio 4.02 first gear instead of the 6.32 granny geared T-18a?

[mandoneer]

t-18-1b is the 4 to 1 rate

[Gwamp]

Originally posted by mandoneer:
t-18-1b is the 4 to 1 ratethanks, that is what I thought. I just wanted to make sure.

[Crazy_Jeepman]

Ummm I would double check that, I have seen the 6.32 to 1 in the 1B case. Put it in 1st, T-Case in Hi, turn the t-case output once, count the trans input, 4 turns 4.02, 6 1/4 is the 6.32. If it came out of a FSJ, I would bet it to be a 6.32 to 1

[Knucklehead]

Hey Gwamp, what do want for that set up?

Jon

[mandoneer]

I will check mine too I assumed that it was the 4 to 1 but who knows

[mandoneer]

yep 4 turns

[mandoneer]

http://www.off-road.com/jeep/tech/trans/t18.html good info on a t-18

[Gwamp]

Originally posted by Crazy_Jeepman:
Ummm I would double check that, I have seen the 6.32 to 1 in the 1B case. Put it in 1st, T-Case in Hi, turn the t-case output once, count the trans input, 4 turns 4.02, 6 1/4 is the 6.32. If it came out of a FSJ, I would bet it to be a 6.32 to 1I will have to try that tomorrow to make sure. Thanks for the tip!

[Gwamp]

Originally posted by 66HD:
Hey Gwamp, what do want for that set up?

JonProbably $250. I just pulled it out and got it inside today. I need to open the cases up and make sure everything is in good shape. the tranny seems to shift fine in and out of gear. The T-case is sticky and needs to be "worked" a bit

[Knucklehead]

Let me know what you find. I'm interested if I can figure out the shipping. You want a new th400 and high range q-trac?

Oh yeah, and what bell housing does that t-18 use (as jeep used about 14 different t-18s)

Jon

[ December 31, 2003, 08:14 PM: Message edited by: 66HD ]

[scotty]

Originally posted by mandoneer:
t-18-1b is the 4 to 1 ratethe casting number has absolutely nothing to do with the ratio. both my t18(from behind a 360) and my friends t18(from behind a 6 cyl) are cast T18-1B as well,and both are the wide ratio-little over 6 1/4 turns in 1st. the only way to verify is to count the turns.

if the t18 is from a FSJ its prolly a wide ratio,i have never know a fsj to come with a 4:1,close ratio t18

if its from a cj,it doesnt really matter,cause the cj guys will pay big bucks for the short input shaft t18,regardless of the ratio smile.gif

also,just a FYI, the link above has one bit of incorrect info- the 80+ t18/208 has a 31 spline output,not 23

[Crazy_Jeepman]

Originally posted by scotty:
</font><blockquote>quote:</font><hr />Originally posted by mandoneer:
t-18-1b is the 4 to 1 ratethe casting number has absolutely nothing to do with the ratio. both my t18(from behind a 360) and my friends t18(from behind a 6 cyl) are cast T18-1B as well,and both are the wide ratio-little over 6 1/4 turns in 1st. the only way to verify is to count the turns.

if the t18 is from a FSJ its prolly a wide ratio,i have never know a fsj to come with a 4:1,close ratio t18

if its from a cj,it doesnt really matter,cause the cj guys will pay big bucks for the short input shaft t18,regardless of the ratio smile.gif

also,just a FYI, the link above has one bit of incorrect info- the 80+ t18/208 has a 31 spline output,not 23</font>[/QUOTE]Yup I agree, have seen the same, and have never ever pulled a 4 to 1 out of a FSJ, though that has only been a couple dozen over the years. tongue.gif

[scotty]

now that i think about it,another friend has a t18 out of a 77 chero,from behind a 360 and its t18-1B as well. im pretty sure that even the t18/208 a friend is running in his xj from an 83 j20 is also cast the same.

[Grantshire]

Weren't the T-18B's all the long shaft FSJ T18's? I have never seen one that didn't have a 6.32:1 first gear. Don't the CJ, Scout and Ford T-18's have short(er) shafts? I think it was some of the Scout T-18's that also came with the 4:1 ratio.

[scotty]

Originally posted by Grantshire:
Weren't the T-18B's all the long shaft FSJ T18's? nope.as mentioned in my 1st post above,a friend is running a 6 cyl t18 in his cj,wich is the "medium" shaft,with a short 1" spacer between the tranny and bell. it is cast t18 1b.

if by "long shaft" you mean a tranny with any spacer between the bell and tranny, i guess that is possible. it may be that "t18 1b" is the designation for any t18 used in a FSJ,as i have not ever really checked any t18s from scouts,fords,or cjs...

[Knucklehead]

Hey Gwamp, what is this combo out of? I'm still interested.

Jon

[Grantshire]

I am by no means an expert on this subject. However, in preparation for my TH400/QT to T-18/Dana 20 swap I have been doing a lot of "investigating". Along the way I have picked up two T-18's. One is a long input shaft T-18B (6.32 1st gear) that came from a mid 70's V8 FSJ. Becasue it was behind a V8 the spacer between the transmission and bellhousing is over 4". The other T-18 (don't know if it is a "B" or not yet - just got it, but it has the 6.32 1st gear) is in the 79 J10 donor truck I just bought and is attached to a 258 6 cylinder. Because the 6 cylinder is a longer engine than the V8 the spacer between the transmission and bellhousing is only about 3/4" thick. The two bellhousings appear to be identical so my bet is so are the front T-18 shafts. The J10 was originally an automatic (based on the steering column) so I don't know its T-18's vintage. Bellhousings from earlier FSJ's were very deep and, therefore, did not have the 4+" or 3/4" spacers.

I also have a 74 Scout II with a T-18/Dana 20 combo. However, it has the close ratio gears (4.?? 1st gear). I have not climbed under it to see what markings are on it but I know it has a much shorter input shaft than my other T-18's. All of the Ford T-18's are also shorter than the FSJ T-18's.

[Gwamp]

Originally posted by 66HD:
Hey Gwamp, what is this combo out of? I'm still interested.

JonIt came out of a 74 J-20. I haven't had a chance to check to ratio. The combo is still in the wheelbarrow in my basement. Do you have a Forward air near by? That is about the only reasonable way to get this to you.

[Knucklehead]

I'll check and see.

So what will I need to get this on the back of a 360. Does this setup have the extension on the front of the tranny and the long input shaft?

thanks

Jon

[Knucklehead]

Gwamp, It looks like there a hub in denver. Let me know

thanks

[Knucklehead]

Gwamp,

You got email

[scotty]

Originally posted by Grantshire:
The two bellhousings appear to be identical so my bet is so are the front T-18 shafts.front t18 shafts?im alittle confused by what you mean there... if youre refering to front drivesahfts,i bet you are right. the spacers are there to make the tranny and t case shifters come thru the same spot in the floor,despite the differences in engine mounting,so the transfer case should be in the same spot,and use the same driveshafts

ill bet,however, when you get the t18 out from behind the 258,youll find that it is also cast t18 1b,and is also the wide ratio. this is the version my friend is running in his cj. smile.gif

the scout t18 has a very deep bell,and around a 9" input shaft,IIRC,so it is about the same length as the 6 cyl t18 with the short spacer.

the ford t18 has a short shaft,like the cj t18(round 6") which is why it is popular to swap into a cj. the t150 bell bolts to it and is the right depth,so the cj guys just need to adapt a d300 or d20 to the other end. a ford or cj version t18 with a d20 is about the shortest granny truck 4 spd you can get,other than the sm420.

for whatever any of that info is worth anyway ;) tongue.gif id defintely be interested to know the casting # of some ford or scout t18s,be they wide or close ratio...

['71j2500]

my t-18 is marked t-18-b1 and has the 6.32 ratio first gear

[Bryan]

Ok, tax return time is coming up and I plan on spending some $$ on the J10, one of the first things I want to do is get a t18. I have a t15 now behind a 258 I6. Do I need a t18 from behind a 258 or can I use one from a v8 and use the t15 bellhousing/spacer since I think thats the only difference???? Thanks...

[Grantshire]

Scotty, I was refering to that sticky outty thing on the front of the transmission (input shaft). Overall length of the input shafts on T18's range from 10" to 16 3/4" (Advanced Adapters lists 9 different lengths between 10" & 16 3/4"). "Stick out" is about 2 5/8" less than overall length. The T-18B I have in the garage has the 16 3/4" input shaft. My guess is that the one in the J10 behind the 258 is also one of the long ones. Both appear to be the wide ratio 6.32 1st gear T-18. The Scout T-18 I believe has a 12 7/8" overall input shaft length and is close ratio (4:1 1st gear). I also believe there is a difference in shaft diameter between the Jeep/Ford T-18's (1 1/16" dia.) and Scout T-18 (1 1/4" dia.). Splines are different too. Some Scouts also came with a T19, where all gears are syncronized (first gear isn't on a T-18).

You are correct that the adapter thickness difference between the V8 and 6 cylinders is to keep the shifter in the same position regardless of engine type.

[Knucklehead]

Gwamp,

I sent you another email.

Jon

[scotty]

Originally posted by Bryan:
Ok, tax return time is coming up and I plan on spending some $$ on the J10, one of the first things I want to do is get a t18. I have a t15 now behind a 258 I6. Do I need a t18 from behind a 258 or can I use one from a v8 and use the t15 bellhousing/spacer since I think thats the only difference???? Thanks...you can use the v8 t18 behind a 6 cyl,however: it will push the tranny and transfer case shifters about 5" rearward,wich may or may not give some interferance prollems with the transfer case shifter and the front seat.

i am running a v8 t18 out of a 77 j20 behind the 258 in my GW. i actually like the position of the shifter where it is now,its ergonomically very nice smile.gif im running a scout d20 behind it with home made twin sticks,and im running plastic racing jeats from summit,so i dont have any clearance prollems there. i do remember when i was running a spicer 18 with factory seats that i had to bend the levers for seat clearance,but that is prolly apples to oranges in comparison to the jeep d20 with the pole shifter.

the other prollem that arrises is that it pushes the tranny crossmember past the rearmost set of holes,and partially past the boxed section of front frame. my stock mount was toast,and i could find another,sp i just located the crossmember with one of rearmost holes,and drilled the other 2 thru the frame. i didnt bother to install a bolt in the top corner that isnt on the boxed section.

obviously this is going to affect the driveshafts as well,so you wont be able to use them from the donor rig. youll be able to shorten the rear shaft to work,but youll need to have the front retubed,or find another one thats too long so you can cut it down.

i just bought all my clutch stuff for a 77 j20 with a 360. the pilot bushing i believe i bought for the 360 as well,and it fit the 258 crank. it has been awhile,so i guess i could be wrong on that-might wanna compare a pilot bushing from a v8 to a 6 before purshasing

grantshire,i gotcha on the stickout length thing-it for soem reason confused me cause of how it was phrased on the 1st post redface.gif

[Bryan]

Thanks Scotty, for the info. Sounds like it might just be easier to find a 6cyl t18. I guess the question still remains though, is it the input shaft and spacer that is different between the 6cyl and v8 t18's, or is there more to it than that. I dont want to have to start drilling holes in the frame and floor if I can avoid it.

[scotty]

yes,that is the only difference. but swapping to a shorter,6 cyl input shaft requires you to a)find the shorter sahft,and b) completely disassemble the tranny to swap it. not out of the range of a DIYer,but there are lots of gears and snap rings,not to mention needle bearings that must be held in place during reassembly with heavy grease or vaseline

for whatever its worth,the new hole for the shifter will be in the tranny cover,wich is a replaceable part if you ever wanted to go back to an auto. the t case sifter im not so sure of-dont remember if a pole-type stock shifter sticks thru the tranny cover or floor itself. my floor has several different holes,now coverd with sheetmetal,from various tranny/x cases in the past ;)

there is not really a way of using the stock crossmember without drilling some holes. only other option would be maybe to design somthing custom

my truck is a trail only rig with no carpet or interior to speak of,and the fabbing doesnt bother me,so for me the v8 tranny worked out pretty well.

youre right tho,if you want a bolt in swap with minimal cutting/welding/drilling finding a 6 cyl version is the way to go

[Grantshire]

Bryan,

There is no difference between the 6 cylinder and V8 T-18's, just the thickness of the spacer. I also believe the same bellhousing was used with the T15 and T18. Look on your rig and see if there is a small spacer (about 3/4") between the transmission and the bellhousing. Also, measure the distance from the shifter to the front of the transmission on the T15 (I believe the overall transmission length is around 9 1/4"). Then measure the same on a T18 (overall length is around 11 7/8"). The difference between the two will be how far back (closer to the seats) the shifter will move when you put a T18 in. The transfer case will also move back about 2 5/8" (difference in transmission lengths). If your T15 does not have the spacer you will need one and everything will move back it's thickness.

Scotty, no problem on the stickout. You were right and I did not mean to mislead anyone with my poor choice of words. Is the Scout Dana 20 a direct bolt up? Do you know anything about swapping internals between the Dana 20 and offset 18 transfer cases to get the lower gearing?

[Bryan]

Scotty & Grantshire, thanks a bunch thats EXACTLY the info I was looking for. Since I'm a marginal backyard mechanic at best I guess I will just look for a t18 from a 258. Anybody got one for sale?

[popeye44]

If anyone trips over a short input shaft holler :D

I've the 16inch one now.. and I got a setup from a 69 J4000 for my baby jeep hehe. "I don't want the extra 8inches taken out of the rear shaft :eek:

[scotty]

Originally posted by Grantshire:
Is the Scout Dana 20 a direct bolt up? Do you know anything about swapping internals between the Dana 20 and offset 18 transfer cases to get the lower gearing?the scout d20 is indeed a direct bolt on. i am using it because it has a d300-like shift tower,instead of the big pole thingy that jeep uses,so fabbing the twin stick shifters was alittle easier.

in a nutshell on the 2.46 swap: youll need a 56 and later spicer 18 with the 1 1/4" diameter intermediate shaft to take the gears from. you then need to find a bronco d20 upper slider(spicer # 18 8 58 or 18 8 37)

no you simply rebuild the d20 with the above gears instead of the stock 20 gears. you will need to clearance the area above the upper slider,on the top of the d20 housing to make room for the larger bronco slider.

here is a link on the swap that youve likely seen: http://www.jeeptech.com/convxfer/2.46-20/

there are some gears that the bronco 20 and 1 1/4 intermediate shaft spicer 18 have in common,and there are some gears that will work,whose spicer #s are not mentioned in the above link. i did a 2.46 conversion using all bronco gears,wich ment modifying the lower shift fork.

there is a more detailed explanation of the different spicer #s and what i did to make it work over here at JU:
http://jeepsunlimited.com/forums/showthread.php?s=&threadid=472498&highlight=bronco+20

since ive been having decent luck with the d20,ill like build a 2.46 20 for myself in the future,out of the few spicer 18 parts i have left that arent broken ;)

[ January 09, 2004, 08:00 AM: Message edited by: scotty ]

[Grantshire]

Thanks, Scotty. I have three Dana 20's (one is in a Scout II behind the Scout T-18), a late 62 Willys twin stick 18 TC, and two Jeep T-18's (one is a T-18B, don't know about the other). I have all winter to build the como to swap into the Cherokee this spring. Just need to to decide what to use and what mods to make.