Repair and Replace 90's YJ

dougiet

Well-known member
Currently I run a 4.0l, 5 speed on 33's with 3.07 gears and I can tell you it's good on fuel but won't crawl on the trails. I am now putting a set of YJ axles (30/35) with 4.10's in with Aussie lockers front and rear and a disc brake conversion on the rear.

I agree with Kunker that you should check out Truck No More. What he built is awesome and I was amazed when he told me he didn't know how to weld when he started!
Thanks for your reply toytech.
Would you have an idea how 31's would perform on gravel roads and trails with 3.07's?
I used a calculator from Currie Products website which calculated 31's with 3.07's increases the ratio to 3.51's.
I am interested in following Kunkers advice to view 'Truck No More' build up and will do just that for sure.
Your reply was really helpful.
I have read that driving to the trail head on the highway is were most of the kilometers add up and only a fraction is driven on the trails I guess.
I would consider 3.91:1 swap in my D35 D30's with a Aussie up front but am reluctant to invest until I see how the YJ performs and what mechanical problems arise.

Thanks again.
 

Richard

Commoner
Club Member
When I first started I had 3.07 gears and 33s and with the manual I added a hand throttle to help on the rocks. It worked but I slipped the clutch a lot. With an automatic it should be ok, you just have to watch the tranny temperature. Bring what you have to the trails in the spring and start having fun, you learn better driving skills with a less capable truck anyways.
 

dougiet

Well-known member
When I first started I had 3.07 gears and 33s and with the manual I added a hand throttle to help on the rocks. It worked but I slipped the clutch a lot. With an automatic it should be ok, you just have to watch the tranny temperature. Bring what you have to the trails in the spring and start having fun, you learn better driving skills with a less capable truck anyways.
Right on.
 

dougiet

Well-known member
Right on.
Richard, All the best for 2022.
I do not want to install a SYE + Cardon. Need to lower shackles to stop driveshaft from falling out, trying to learn minimum lengths and raise belly pan up and remove pan spacers.
 

2Greys

Insert title here
Club Member
At this time on this YJ the tires, axles, springs, and shocks are a blank canvas to replace with the next right step. These components are worn from sitting parked for years, dried bushings, only steel axles, a sandwich locker in the 35, open in the 30 YJ with no disconnect installed, and a 3.07 ratio. So the type of driving I am considering is leaning toward an all-around driver ready for the blacktop to get to the trailhead then have clearance, gears, and tire size to trail ride, so I can watch and see the different setups and how they perform, meet people then decide, is more going to be necessary. I would prefer to keep as many of the axles components as possible and match tire size to gear ratio with the stock TF A 727 3 speed, NP 231 T.C., and 258 carburetor.

The age-old topic of gear ratios to tires, size and type of offroading trails is a big combination for me to consider. After a couple of years out there with more knowledge, I could possibly sell off the YJ for something else or become a more skilled driver with the YJ.

Right now I am lost to understand how a 3 speed tranny with a four and a half thousand rpm 258 carb motor works and behaves on 33's with 3.07 gears???

Thanks, Kunker and 2Greys.
When I first did 33's I planned on getting the tires and regearing to 4.10 a while later. Then having to downshift from 5 to 4 for the little hill heading west on the 417 after Nicolas pushed those plans ahead of schedule (I have low tolerance tbh so YMMV). That was 3.07's with AX15 and a 4L
 

dougiet

Well-known member
2Greys, driving this YJ on a 400 series highway will not happen! 25 years ago I would. I just can't wait to drive this little rig down any road.
The new cars are very safe to drive with advanced safety features but most drivers don't know how to drive.
Gas mileage is what it is. Slowing down on hills is a problem and you did the right thing to regear.

Sophie, my little dog is recovering well from her surgeries, one tough cookie.
 

Kunker

Administrator
Club Member
Personally, I'd be researching to see how hard it is to stick in one of the AW4 transmissions Dwayne is selling. I assume it's pretty much a bolt in given that they came in the XJ's, and it gets you overdrive. The downside is I think you'd be manually shifting the trans. But as I said, I overthink things and make projects bigger than they need to be. If you aren't going to be tooling down the road constantly, it's probably not worth it.
 

dougiet

Well-known member
For sure, you can label my jeep now as a Weekend Overlander. I am on a learning curve and having fun.
The more I dig in the more I get back.
The TF 999 tranny installed has an ajustable kick-down rod.
Kickdown is a downshift in an automatic transmission triggered when the driver pushes the car’s accelerator to the floor.

Automatic transmissions kick down to a lower gear to make use of the greater power delivered at the engine’s higher rpm; this typically occurs when the driver attempts to accelerate from a constant speed, as if to pass.

Thanks, Kunker.
 

dougiet

Well-known member
Wanted, Inners for Tube fenders. Yes, it is a YJ chassis but TJ inners will hole up with TJ grill mounting bolt holes.
There are mounting brackets on the Tube outer fenders for inners and I am guessing a TJ inner is best.
Advice is welcome.
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Logan

apparently the prezident
Club Member
Personally, I'd be researching to see how hard it is to stick in one of the AW4 transmissions Dwayne is selling. I assume it's pretty much a bolt in given that they came in the XJ's, and it gets you overdrive. The downside is I think you'd be manually shifting the trans. But as I said, I overthink things and make projects bigger than they need to be. If you aren't going to be tooling down the road constantly, it's probably not worth it.
I have a writeup saved somewhere for doing the AW4 swap into my TJ. Not sure what all would be different for the YJ though. There may be a write up on it somewhere. From my understanding its a fairly easy swap. Just need to do some wiring as the AW4 is electronically controlled with its own TCU.
 

dougiet

Well-known member
Two heads-up comments about the AW4, I will check it out.

The Aisin-Warner four-speed automatic transmission (AW4). It doesn't seem that hard to swap into a YJ, the electronics are simple and my jeep has the 4.0 wire harness installed.
I am out to get the YJ certified this spring so I can drive to a garage when needed. The 3 speed TF999 feel reminds me of driving heavy equipment I used to drive for many years starting as a young teenager, on to Heavy Equipment College then running a Case 580b and 680b and a Massey Furguson tractor forklift with a 3-speed auto tranny for over 20 some years. So now instead of grunt work, I can bomb around in the YJ.
That's the plan.
 
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