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T-18 Questions

T-18 Questions
stoney bones

stoney bones

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273
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Location
michigan
Vehicle(s)
81 CJ7

258ci, mc2100 ,SR4 trans, dana 300 Tcase, dana 30 front, amc 20 2 piece rear
I've just found a gentleman with a T-18 attached to a Transfer Case and bell housing off of an 88 chevy full size truck.

I know the T-18 itself with adapters will bolt to my AMC 258 i6 / 4.2l but, would i be able to use the bell housing or Transfer Case ?

he says it has never been rebuilt, and has approx 60k - 70k miles. asking for $300

whats the Transmission alone worth?
 
The bellhousing is a NoGo, unless your planning a Small Block Chevy swap.
The Transfer Case output is on the correct side for a Jeep front axle.
 
i should have known the bell housing wouldnt work. lol

any idea what Transfer Case it might be? he said he had no idea and i havnt seen it in person to try and identify.

i think i may go ahead and purchase it. he said he was not firm on the price if i get out there soon.
 
I'm not a big chevy guy, but IMO it's a NP241 which is chain drive.
 
Make sure it is the T-18 with the granny low. There is a T-18 without the extra low gear. He should know which one it is and you can always check by turning the input shaft as long as the T Case is in high range, 1:1. It's not that easy to swap in a T 18 but well worth the effort.

Tommy
 



NP241C
Starting in about 1987, the New Process 231/241 series Transfer Case became standard in Jeep, Dodge, and Chevrolet applications. These transfer cases are part time 4WD (Shift positions 4HI - 2HI - N - 4L). They have a relatively thin aluminum housing. They are 1:1 direct drive in high range, and use planetary reduction gears for low range with a ratio of 2.72:1 They use chain drive for the front output. The NP241 was typically used in V8 applications.

Exact identification:

These New Process cases have a circular plate, about 2" in dia., on the rear of the case, in the center. Full identification info for the case is on this plate

Bolt Pattern:

Jeep, Dodge and Chevy versions all use a 6 bolt circular bolt pattern. This pattern is NOT symmetrical and will only bolt up one way. You can typically bolt a Jeep unit to a Dodge Transmission and vice versa, however Chevrolet units are NOT cross compatible: While GM uses the same 6 bolt patter, they have it rotate approximately 90 degrees from that used by jeep dodge.

In all of these 6 bolt applications the Klune-V Extreme Underdrive will bolt up to these transfer cases directly with adapters necessary. Some may require a spacer.

Slip-Yoke Eliminator

All of these units we have seen have been equipped with a slip-yoke rear output. Slip-Yoke Eliminator kits are available for most of these transfer cases

Jeep / Dodge Units:

All of these cases have a left hand drop (front drive shaft on driver's side).

Input Spline: most applications use a 23 spline female input shaft.

All Dodge Cummins or V10 NV4500HD application 241s use a 29 spline. Also 99-up NV4500 standard duty gas apps

GM New Process 241 Transfer Case

In 1988, GM began using the NP241 transfer cases. Most of these units will be right hand drop, but Chevy also used a few left hand drop applications. The Chevy NP241 is supplied with a 27 spline female input or a 32 spline female input. With a T350, 4L60E or 700R4 tranny, it will be 27 spline. With a T400 or 4L80E Transmission or 5 speed, it will be 32 spline.

Transfer Case Shifter

In most cases the stock Transfer Case shifter can be retained in the stock location. The linkage rod will need to be extended. This is done by cutting the existing rod in the middle, slipping an appropriate length of steel tubing over the ends of the cut pieces, and welding in place.
 
well pretty sure im going to go for it. i sent novak an e-mail to ask about adapters and and other needed parts. just waiting on a response from them. i was looking for an AX-15 but only found 2 in my area. 1 was in pieces and the other, the guy wasnt even sure after second thought if it was an ax15 and didnt want to try and ID it.

i know the ax15 goes right in since they originally came with one at one point. but i was under the impression the T-18 is a way better choice. should i keep looking for an AX15 or is this T-18 going to be worth it just for the granny gear alone? will i notice the difference between the durability of the two since i wont being doing any hardcore wheeling?
 
also, thanks long horn for that info, very useful.
 
If you’re looking for an over drive Transmission the T-18 isn't it. it also weighs about a half a ton. :D
 
stoney bones said:
well pretty sure im going to go for it. i sent novak an e-mail to ask about adapters and and other needed parts. just waiting on a response from them. i was looking for an AX-15 but only found 2 in my area. 1 was in pieces and the other, the guy wasnt even sure after second thought if it was an ax15 and didnt want to try and ID it.

i know the ax15 goes right in since they originally came with one at one point. but i was under the impression the T-18 is a way better choice. should i keep looking for an AX15 or is this T-18 going to be worth it just for the granny gear alone? will i notice the difference between the durability of the two since i wont being doing any hardcore wheeling?
Click to expand...

What Jeep are you swapping the tranny into?
CJ's never came with a AX15.
As far as the T-18 goes I've swapped one into my 81' CJ5 & my wifes 88' YJ.
I swapped a wide ratio T-19 into my CJ8 , the difference between the T-18 & the T-19 is the 19 has a full syncro 1st gear.
In retrospect the full syncro 1st gear real makes no difference.
IMHO the T-18 is the way to go, you run a hwy gear in the differentials.
Which leaves more teeth on the pinion gear so stronger.
The T-18 is stronger than the AX15.
Some people might not think of 4.56 gears as hwy, but with 38" tires 3000 rpm = 74 mph which is pretty much O/D territory & stronger all the way around.
Sorry to run on.:cool:
 
As I stated earlier, it's not an easy swap but it's well worth it. It's as tough as they come and the granny low will get you anywhere you want to go without straining. Can't think of a better upgrade. I swapped one into my '81 CJ5 last year and love it. The total cost with all I had to do was around $800.

Tommy
 
Are you sure it's a T-18 from a Chevy? I never heard of a T-18 in a Chevy. Don't get started on this to find out you have a Transmission "similar to a T-18 ".
 
busa, he did say it was from a chevy..maybe he forgot to mention it was in something else first.

i was thinking i wanted the over drive, but in reality...i rarely drive over 55 as it is. i work from home, 1.5 miles out of town...also may get a new vehicle this fall for a daily driver. i may just pass this up to give this some longer thought and see what else is out there.


im gonna send those T-18 pics to my phone so i can compare if i do end up going to check this out.

thanks for all the help!
 
There are several different T-18 variations. You need to know what it came out of. The bolt pattern and input shaft length varies on the different versions.
The T-18 is an excellent heavy duty Transmission . It's a truck Transmission so it doesn't have the smooth short shifts of a car.
Since it comes with a TCase you shouldn't have to worry about that end but you may need to fabricate a crossmember.
Many T18s have a granny low 1st. If your tires are over sized and you are geared tall you could start out in 1st and then 4th would almost be like an Overdrive .
I have a T-18 in my CJ5 and I swapped a Ford T-18 into the CJ7 I used to have.
 
well just found a T-18 and NP208 out of a 1980 ford f150. left a message, just waiting for a response.
 
stoney bones said:
well just found a T-18 and NP208 out of a 1980 ford f150. left a message, just waiting for a response.
Click to expand...
That would be an easy swap. The T-18 input shaft is the correct length. To bolt the tranny to your Jeep bellhousing you will have to drill and tap 4 holes.

EDIT: I think you will need to change the lengths of the drive shafts.
 
Last edited:
LongHorn said:
IO's right the T-18 ain't light, but in reality it's about AMC 150 lbs. ;)
Click to expand...
Yeah, that's about right, but when it's bolted to a heavy arse cast iron Dana 20 Transfer Case and you're laying on your back trying to install it by yourself, it feels like a ton! :eek:

I've installed a whole lot of trannies in my life, and that combo was by far the heaviest.
 
BusaDave9 said:
That would be an easy swap. The T-18 input shaft is the correct length. To bolt the tranny to your Jeep bellhousing you will have to drill and tap 4 holes.

EDIT: I think you will need to change the lengths of the drive shafts.
Click to expand...
The question is, does the 1980 Ford version have the 6.32 to 1 1st gear? I have no idea? I think I was really lucky to find an original 1979 Jeep T-18 out of a CJ5 so I didn't have to spend more on adapters than I spent on the tranny. :cool:
 
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