new CJ owner, need advice

[stoney bones]

hello everyone, this will be my first post. i just recently purchased an 81 CJ7 with the AMC 258 i6 / 4.2l . there is already so many things i want to do. i thought i would ask for some advice from some people with experience.

i would like to use this as a daily driver for the most part. but, it will not be used for commuting to work or doing any express way driving. not sure i have ever drove it over 55 yet lol.

so i guess i want daily driver reliability with trail potential. i dont want to muddin or rock crawling. just some good fun trails. so, for this i figure i will keep the AMC 258 i6 / 4.2l in it. but, it definetly needs more get up and go. this is where i need advice. i have been reading about the 4.0 head swap. sounds like a plan to me. other than that, what else in the drive train do you think i should change? the Transmission is having problems getting into 2nd from 3rd here and there...so i can predict changing that out soon.

current setup:
AMC 258 i6 / 4.2l
carter 1bbl carb
Dana 300 T case
SR4 Transmission
Dana 30 front
AMC20 rear

i want to beef it all up. suggestions on where to begin?

 

[priceg]

Welcome to the site. You will soon have more information than you can possible process

 

[stoney bones]

i suppose i'll try asking a more specific question.

whats the pros/cons between the AX15 and the T-18 transmissions?
i like the idea of 5 speed because familiarity and experience but would the T-18 be better? my CJ will mainly be daily driver with bi-weekly trips to some trails. no mud holes or rocks in my plans.

 

[Old Dog]

Here's some of my thoughts.
for a DD there's really no need in a T-18 , people use it for the granny 1st gear which you have no real need.
If I were you I would change the Transmission fluid and make sure you put gl-4 in it, someone may have put gl-5 in it and may be why it's not shifting so good.
Check your gear ratio, if you have 2:73's that maybe why your don't have much power.
I would put 1 piece axles in the rear, as the stock one tend to spin hubs.
What size tires do you plan to run?

 

[stoney bones]

Here's some of my thoughts.
for a DD there's really no need in a T-18 , people use it for the granny 1st gear which you have no real need.
If I were you I would change the Transmission fluid and make sure you put gl-4 in it, someone may have put gl-5 in it and may be why it's not shifting so good.
Check your gear ratio, if you have 2:73's that maybe why your don't have much power.
I would put 1 piece axles in the rear, as the stock one tend to spin hubs.
What size tires do you plan to run?

good point about the granny gear. i think i will definetly change out the fluid just to see.

ive read a bit about the 1 piece axle conversion, just trying to locate a good place for the parts. right now i have 33 x 12.5 tires and i dont really think i have a need to go any larger...

 

[Old Dog]

If your running 33's I'd check to see if you have 2:73 gears, that gearing will suck a lot of power out of that AMC 258 i6 / 4.2l .

 

[derf]

x2 on checking your factory gear ratio.

Swapping in an Overdrive Transmission in place of one without Overdrive can leave you not being able to make any use out of the Overdrive until you regear the axles. There are good gear ratio calculators out there (like mine...) that will let you figure out what gears you want to run.

When it comes to swapping out transmissions and gear ratios, you really want to have a firm overall picture of where you're going so you only do the expensive stuff once.

The SR4 is really an inadequate Transmission and I would seriously look at it being the first thing to go. The AX-15 would be a great Transmission for a driver/moderate wheeler. They're not too hard to find in the junkyards and they will hold up to a AMC 258 i6 / 4.2l just fine. A newer Transmission from the Wranglers is the NV3550. It's roughly on par with the AX-15 and a good alternative if you find one of those first. When you regear the axles to match your tires and the new Overdrive , you may find you have more than enough power for what you want to do. Or at that point you can decide to do the 4.0 head swap to get more out of the engine you have.

 

[stoney bones]

great information. thanks a lot. im going to be checking out that calculator for sure. i am also for sure going to get rid of this Transmission and thanks for the suggestion on nv3550, ill keep an eye out for one of those as well.

i agree with your feelings on the gear ratio. i had an xj with the 4.0 and 32in tires that had way more get up and go than this. sometimes when starting off i swear it feels like i put it in third...but nope thats 1st.

im already looking into the 4.0 head swap, after reading a bit about it i can tell it would definitely be a great choice.

so it looks like my list so far is:

Transmission swap
head swap
2 piece rear axle conversion
proper axle gearing