renix/ tranny questions

I am not really sure where to put this, but here it is, 2 different questions, that I would like to get everyones opion on.
First, what does everyone think of the RENIX Systems?
Second, what does everyone prefer for wheeling, auto or manual tranny?
Sorry if this is not the right place to post, and thanks for all that reply.

Nah - OEM Tech seems about right...

You'll get varying answers to both questions. I happen to prefer RENIX over OBD - but I'm used to doing my own thinking, and that seems to set me apart from most "techs" these days (I came up on points & condensers, you had to do your own thinking there!) The RENIX control system is robust and reliable (I've only personally heard of three failed ECUs to date. I have two of them,) and most of the sensors (save the HEGO and TPS) are standard GM parts and can therefore be found pretty much anywhere for a nominal cost.

If not RENIX, I'd go OBD-II - while it's a bigger pain to modify, at least the system was standardised by SAE (instead of simply mandated by CARB, and impelementation left up to the manufacturer.) OBD-II is 1996 and up on all lines.

Transmission preference? Where do you plan to wheel? What do you plan to do with the rig when you aren't wheeling? What sort of axle gearing and what size tyres do you plan to run? And those are just the big questions...

Its atleast right now a daily driver, i live in the mountains by yosemite in cal, so I find a manual is better for me for highway, but I have not really done any wheeling in a manual, mostly I would be running bumpy forest service roads, and alot of snow and mud in the winter.

LOVE the Renix--you can test it all out with a multimeter. If you grew up using a test light and a feeler gauge for setting points, and can remember the joy of your first tach/dwell meter, then the Renix is like a trip down memory lane.

OBDI, 91-95, is more tolerant of mods than the OBDII of 96-01 which can start throwing codes when it isn't in its comfort zone. The biggest problem of the OBD systems is that some a**ume that the code definition is the final word, and replace parts based on that simplistic a**umption--sometimes a very expensive mistake. If you keep in mind that the code is just the ECU/PCM telling you that something is not giving it the expected information, and that the system is essentially a half-wit, then you can do Ok with it.

My first two Jeeps were both sticks--1946 CJ2A and 1953 Willys Wagon. Guess I just got used to wheeling and clutching. Of course these days with my XJ w/AX15 and back issues, I have to wear a four-point harness or three hours of fun ends up being a week or more of pain.

Seems that some of the serious wheelers put electronic shift controls on their AW4s to control things like a manual, but without the clutch.

Love my renix And aw4 not so happy with np242

We have one of each, 90 Renix, 93 OBD2 and carbed 2.8 86 XJs. By far the Renix is the easiest to diagnose, all you need is a good multi meter. The OBD2 comes in a close second, I can diagnose most of it with a multi meter and FSM. The carbed 2.8 is a pain in the ass, if it didn't run as good as it does I'd rip it out and put in a Renix 4.0. Neighbor has a 98 OBD3 that I do some work on, he had to buy a scanner just so we could diagnose it.

As for transmissions, I'm lazy, so auto is my choice.

stesul411 said:

We have one of each, 90 Renix, 93 OBD2 and carbed 2.8 86 XJs. By far the Renix is the easiest to diagnose, all you need is a good multi meter. The OBD2 comes in a close second, I can diagnose most of it with a multi meter and FSM. The carbed 2.8 is a pain in the ass, if it didn't run as good as it does I'd rip it out and put in a Renix 4.0. Neighbor has a 98 OBD3 that I do some work on, he had to buy a scanner just so we could diagnose it.

As for transmissions, I'm lazy, so auto is my choice.

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Your 1993 is OBD-I. The neighbour's 1998 will be OBD-II.12

Generations run:
RENIX: 1984-1990 w/AMC gasoline engine (150ci or 242ci)
OBD-I: 1984-1986 w/GM V6 engine; 1991-1995 w/gasoline engine (I'm unsure about the VM turbo Diesel.)
OBD-II: 1996-up, all engines (spec'd by SAE.)

Hi, All.

to sort of put a spin on the OP's post... what do you think: is manual tranny or auto tranny better for daily driving? maintenance? general lifetime of MT vs AT?

5-90 said:

Your 1993 is OBD-I. The neighbour's 1998 will be OBD-II.12

Generations run:
RENIX: 1984-1990 w/AMC gasoline engine (150ci or 242ci)
OBD-I: 1984-1986 w/GM V6 engine; 1991-1995 w/gasoline engine (I'm unsure about the VM turbo Diesel.)
OBD-II: 1996-up, all engines (spec'd by SAE.)

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Yah you're right, just got my 2's and 3's messed up.

The older I get the more I like my AW4. No slipping clutch to be concerned with and with the older models you can control which gear your in. To the point of locking up the TC in 1st.

I just recently had a chance to chat with tranny guy at a really big Dodge dealership. He has been working on Chrysler transmissions for years, and he said the AW4 auto is one of the best trannies out there.

From what I've seen, most people prefer autos for wheeling. You'll always find a few die hard stick guys thouh .... I'd say if you are on the fence - go auto.

Oh, and my 87 Renix runs like a top.

stesul411 said:

Yah you're right, just got my 2's and 3's messed up.

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There is no current OBD-III spec - AFAIK, it's still in the planning stages. OBD-II has been mildly enhanced over the years, but that's as far as it's gotten.

love the renix system

i have the ba-10 manual trans in my 89 which has lasted 248k miles, but is known to be a light duty trans. the ax-15 was introduced in 89 1/2 and is a good trans.

as for wheeling, auto trans is easier. problem i have when wheeling with a manual is being able to control the clutch, brake, and gas at the same time while being thrown around in the seat. i still prefer to have a manual trans in my xj and muscle car but prefer auto in my family car.

Ive only put about 200 miles on my renix, but I love it already.
The 89 w/4" lift rides better than my girlfriends 96.
Some people claim better gas mileage w/renix, and the renix system can be tested with a multimeter.

I have owned 2 renix xjs, and my buddys both own obd-1 xjs.. I know my jeep, i know what that squeek is, i know why it stops running within 10 minutes of it dieing (has happened 3 times now) they just seem much easier to work on..

On a downside to the renix, the brake systems are not up to par.. you need to upgrade the booster/master from a 95+ model..

If you get a renix with a 231, then you get a vacuum assist Front axle, so you need to upgrade that.. (fine with me, i prefer the 242 and full-time 4wd option)

Unless your renix has abs (witch is junk anyway!) then you also need to upgrade axle shafts if you plan to go bigger then 31" tires..

with the renix being older, you will find small issues such as losing power at electric doorlocks. and one-wire alternators.. Upgrading grounds in any XJ is almost required.. but the renix especially..

I personally have the opinion that the renix motor will last longer then a HO with proper maintenance.. (although i have nothing to support this)

The AW-4 is a great transmission, i have yet to have a problem outside of a bad Pan gasket..

i have heard that 5 speeds tend to be weaker, and wheeling can get tricky with all the multi-tasking and concentration that is required.. I have an Aw-4, i normally prefer manual..

nw-xj-scott said:

If you get a renix with a 231, then you get a vacuum assist Front axle, so you need to upgrade that.. (fine with me, i prefer the 242 and full-time 4wd option)

Unless your renix has abs (witch is junk anyway!) then you also need to upgrade axle shafts if you plan to go bigger then 31" tires.

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why do you need to upgrade the CAD? mine still workds fine. its just like anything else with a vehicle, it requires maintenance.

the reason for the axle upgrade in the dana30 is to get the larger ujoints, the shafts themselves are not an upgrade. it depends on the type of wheeling you do as to whether you NEED to upgrade. lots of renix jeeps running 31" and up tires out there with out the larger ujoint upgrade

89xj said:

why do you need to upgrade the CAD? mine still workds fine. its just like anything else with a vehicle, it requires maintenance.

the reason for the axle upgrade in the dana30 is to get the larger ujoints, the shafts themselves are not an upgrade. it depends on the type of wheeling you do as to whether you NEED to upgrade. lots of renix jeeps running 31" and up tires out there with out the larger ujoint upgrade

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Sure, on the road those smaller joints will be fine. If you wheel, this WILL happen!!

MrSimon said:

Sure, on the road those smaller joints will be fine. If you wheel, this WILL happen!!

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not saying its not a good idea to upgrade, but just because you snapped the 260 ujoint, means everyone should upgrade? with this logic, wheeling with the d35 cant be done.

it all depends on the type of wheeling you do. also, driving on road can be just as hard on parts as off road because of the traction the tires can get.

My xjs:

Wheeled:
90 Auto
90 Stick
90 Auto
95 Stick

Not wheeled:
92 Auto
97 Stick


I prefer the RENIX alot. 4 three jeeps I wheeled were also DD's. The other 2 were stock back ups/buds jeep i would use occasionally. Renix was/is easy to work on and cheap. However the HO's do feel like they pack a little more power (especially feel it in the standards). I prefer driving a stick on the road. I didn't like wheeling with a stick until after I got slightly geared (3.07s on 31's= bad, 3.55 on 31s felt great). My current xj is an auto. I love wheeling it but I am actively looking for an AX-15 swap, I miss DD'in with a standard (I'll trade anyone looking to do the opposite lol)

89xj said:

not saying its not a good idea to upgrade, but just because you snapped the 260 ujoint, means everyone should upgrade? with this logic, wheeling with the d35 cant be done.

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Not just because I snapped one, but because almost everyone I've ever talked to who runs (or used to run) 260 joints has snapped at least one. All while wheeling though - I've never personally heard of someone snapping a u-joint from normal road driving.