transmission choice opinions

[JR74CJ5]

Ive beem told the T-15 is a pretty good and strong tranny. Just had mine rebuilt. But im not running tites as big as yours...

From what ive heard though its a great 3 speed... The T-150 however ive heard is pretty weak, but im not too sure either way


Jr

 

[Out of my mind CJ5]

i passed on the T-150 , the Dana 300 ended up being a Dana 20 , seeing as the T-15 and T-18 have the same final gear ratio would it really make sense to swap to T-18 ? does anyone know or heard of running a -15 with a drivetrain that big?

 

[boomer]

Out, It isn't the 4th gear ratio your looking for that 6:32/1 ratio in the T-18 , t19 is what your getting plus you are getting a super strong tranny. Threr is a T-18 out of a Jeep On ksl.com Classifieds Auto Parts and Accessories under Powertrain/Transmission on June 13, 2011 for sale while your there you may want to shop the whole section it gets fairly interesting for parts.There are other trannies and transfercases there also as well as other related parts. I know that Utah is a long way away but you never know.

 

[cerial]

It all comes down to what you want for a craw ratio. The T-18 was put in large trucks and is really tough. It can handle a lot of torque. Behind the T-18 you could put a Dana 18 but only if your rear drive-shaft has a ps drop. If not a Dana 20 is a bolt on option.
Herm the Overdrive guy makes a warn/saturn Overdrive that gives you the ability to split the gears in the Dana 18 giving you a 8 speed. The Dana 18 is also extremely stout and can take a lot of abuse.

 

[Saddle Tramp]

If you want to go cheap with the AMC 401 the T-18 /T19 Transmission is the only way to go. They are 2-1/2 ton truck rated and available. If you are fortunate enough to find a CJ T-18 it will be your best option. The cost of a CJ T-18 will be higher than the Ford version but the cost of the Ford version and the adaptors may be less. All AMC I6’s and V8s have the same bell housing bolt pattern and the CJ bell housings from 1977 to 1979 were drilled and tapped for both the CJ T-18 and the Ford “butterfly” pattern allowing for the uses of either Transmission without an adaptor. (sort of). I say sort of as the Ford input shaft is about 7/8” +/- shorter than the CJ version shaft. This requires a special pilot bushing to make up for the difference. Some say it is a pilot bushing and not an adaptor but to me if it cost extra money it is an adaptor.

The back of the CJ T-18 has an adaptor to mate to the Dana 20 Transfer Case that in reality is part of and comes with the case. With the Ford T-18 the back of the Transmission needs to be rebuilt with a kit/adaptor to change the output shaft length and a plate to accept the Dana 20 . The price of all of the kits/adaptors adds up; this is why I state that a CJ T-18 may be cheaper in the long run. If you can find a T19 form a Scout it will bolt up like a CJ T-18 .

Take a look at this:
http://www.jeeptech.com/convtrans/cjt18/

 

[Out of my mind CJ5]

is the t18A the same thing found in the cherokees and wagoneers? i thought that one had the 5 inch spacer that was bad for cj's and on a random side note i am now in search of a front axle as the 44 front i have cannot have the 4.10 ratio im looking for, so does anybody have suggestions on any good ones keeping in mind it has to be 8 lug? i have heard people like chevy fronts but what years and trucks if anybody knows i cant seem to find it online? once again thanks for all the help with my questions

 

[BusaDave9]

is the t18A the same thing found in the cherokees and wagoneers? i thought that one had the 5 inch spacer that was bad for cj's

You are correct. Most full sized jeeps with T-18 's had a spacer that would have to be removed and then you would need to replace the long input shaft with a short one.

on a random side note i am now in search of a front axle as the 44 front i have cannot have the 4.10 ratio im looking for

Why can't you get the 4.10 ratio?
Weren't you going to run 37 inch tires? If so you would want to go to at least 4.88 gears.

 

[Out of my mind CJ5]

the Dana 44 i have is out of a 78 j20 pickup and apparently they do not make a 4.10 gear set for it they make a 4.09 and a 4.56 but no 4.10 yes im running 37 inch tires, i thought with a 4.10 it would leave a half way decent ratio for when it does see the street

 

[Out of my mind CJ5]

plus i am looking for something that already has the high steer knuckles on it and match my rear axle a little bit better, right now my front axle is 4 inches narrower than the rear

 

[BusaDave9]

the Dana 44 i have is out of a 78 j20 pickup and apparently they do not make a 4.10 gear set for it they make a 4.09 and a 4.56 but no 4.10 yes im running 37 inch tires, i thought with a 4.10 it would leave a half way decent ratio for when it does see the street

4.09 and 4.10 are more than close enough to match.
Plus if you want a half way decent ratio fro the street then 4.88 will bring your RPM's back to what the factory came with (compensating for tire size).
4.1 gears will be much too tall for 37 inch tires.
Check out this chart. You want to shoot for anything in the green.

 

[BusaDave9]

4.09 and 4.10 gear sets have only 0.25% difference. These gear sets will work on the same 4x4.
Check out this link: Randy's Ring & Pinion.

As long as the front and rear ratios are within 1%, the vehicle works just fine on the road, and can even be as different as 2% for off-road use with no side effects

But you still don't want to use those gears on any tires bigger than 33 inches.

 

[Out of my mind CJ5]

thanks for the link it helped clear up some questions i had, it is looking like i might be looking for a chevy front axle now as some already have the high steer knuckles on them and they will closer match my rear axle width, does anyone have advice on what year trucks i should be looking at and what type, has to be 8 lug

 

[Old Dog]

But you still don't want to use those gears on any tires bigger than 33 inches.

Dave, do you say this because you think the overall gearing would be to high?

thanks for the link it helped clear up some questions i had, it is looking like i might be looking for a chevy front axle now as some already have the high steer knuckles on them and they will closer match my rear axle width, does anyone have advice on what year trucks i should be looking at and what type, has to be 8 lug

Here's a good link on Dana 44 's
Mr.N's Dana 44 Flatop Knuckles

 

[BusaDave9]

Dave, do you say this because you think the overall gearing would be to high?

yes, 4.1 gears are good for up to 33 inch tires but you should have 4.88 or 5.13 gears for 37 inch tires.

 

[IOPort51]

are you saying not to use 4.10 gears with tires larger than 33 or not to mix and match ratios with tires larger than 33??

4.09 and 4.10 gear sets have only 0.25% difference. These gear sets will work on the same 4x4.
Check out this link: Randy's Ring & Pinion.

But you still don't want to use those gears on any tires bigger than 33 inches.

 

[IOPort51]

tell me more about the chart Dave. who chart is it and what factors are deciding the range of tire size to axle ratio?

 

[BusaDave9]

You can mix and match ratios as long as they are within 1% of each other. Tire size doesn't matter when mixing and matching ratios.

The chart I showed displays engine RPM at 65 MPH. You want to use any combination of tire size and gear that fall in the green. If you follow 37 inch tires over to the green you will need 4.88 or 5.13 gear ratio to keep the RPM at about what the factory had with OEM tires.

 

[BusaDave9]

tell me more about the chart Dave. who chart is it and what factors are deciding the range of tire size to axle ratio?

I once found the equation to calculate the RPMs for a certain tire size and gear ratio. I calculated out the chard in Excel. There are lots of other charts on the internet that have the same numbers but I can't find the site that I found the original equation.
Guide on gear ratios - Team-BHP





Jeep Parts, Jeep Accessories, Gear Ratio Calculator - OMIX-ADA

Jeep Ratio Calculators

 

[LongHorn]

IMHO that charts great for Colorado, but I like to run more to high side since I'm running a granny gear.
I like to run a highway gear ( For me a 4.56 with a 38" tire) so I run about 2800rpm at 70mph.
It works well for me anyway.

 

[IOPort51]

with the peek torque on the AMC 304 being about at 2500 RPM I can see where this is a good chart for you. I am thinking at this moment that with the AMC 258 i6 / 4.2l the prime RPM range may be a bit lower. Closer to 2K. This may be some sad rationalization to justify my 3.54 axles but this is my opinion for the moment at least.