CJ Upgrade Questions

Hello,

I am a rookie so bear with me. However, I am an engineer and not new to mechanics and money isn't really an issue with upgrades.

I am rebuilding a 1979 CJ5 Silver Anniversary Edition I picked up.... well, I picked up what is left of one and will try to breath new life into it.

I am not looking for stock and plan to only keep the body looking original while upgrading axles, drivetrain, electronics, and suspension.

I want everyone's opinion on the best upgrades for the following:

T5 Transmission
Best gears? 32 tooth vs 34 tooth cluster gear
10 spline vs 14 spline input shaft
29 tooth vs 27 tooth 3rd gear
23 tooth vs 25 tooth 5th gear
buying gears with or without needle bearings

Dana 300 Transfer Case
best gear upgrades for the T-case
what is 4:1 gearing and how is it a benefit?

Dana 44 wide track front
Best gear ratios with the dana 300 and t5 and 33" maybe 34" tires
Best upgrades as far as brakes, lockers, and other choices

Dana 44 wide track rear
Best gear ratios with the dana 300 and t5 and 33" maybe 34" tires
Best upgrades as far as brakes, lockers, and other choices

Will post questions about my 258 engine when that comes.... maybe a year out before I touch it.
Will most likely be running a fuel injection and EFI along with a push button start (w/ kill switch of course).

 

What do you want to do with the jeep? ice cream ride of off-road use?
A T5 for off-road ain't a good choice, find yourself a t18 with a 6.32 first gear ratio. This way you wont need to re-gear the t-case so less stress on it.
Axle find some scout/chevy/waggonner axle and swap them under the jeep and put the locker you want depending on the budget you have. Arb or e-locker are around 1000$ each and other like spartan of lock-right is about 350$ each.

For 33-34" tire keep the oem axle an upgrade the rear shaft to one piece axle, dana 44 is good thinking when having 35's inch tire.

 

Best locker IMO is a cable actuated OX hands down.

4.1 gearing is a form of, well, gearing that reduces the speed your vehicle moves at (please excuse ultra laymans terms, I don't really know how to explain).

What you should do right now are two things.

Decide, what is your Jeep going to be for?

Also, did you wheel this jeep much before tearing into it? Get a feel for the crawl ratio in all gears?

What you should do is based on your experience driving it previous, look at options such as a truck transmission and 4.1 gearing.

For me, I can't sacrifice the relatively high gearing on my D-18, it's perfect for a lot of what I do, but an extra gear would be nice to do some trails without beating the clutch. So for me, 4.1 would actually be a detriment, but a T-18 transmission with a 6.32 first would get me an ideal set up.

Understand what I'm trying to explain at all?

 

I'm also on the band wagon with T-18 and spend NO money upgrading the T5. Adapt to the stock 300. With 33" tires, I'd go with 4.10 or 4.56 gears. Honestly, with my '79 CJ-5 the idea of running 70 mph for any real time is NUTS, so overdrive not needed. Maybe after I put more highway miles on it I'll change my tune? But 84.5" wheel base and 33" tires and at least with mine's manual steering box, NO THANKS! 55-60 is nice and 4.10 would put you about 2500 rpm at that speed.

Money being no object, the OX Lockers would be my choice over ARB because of the all mechanical aspect. With that said, plans for my own include a narrowed Dana 60 for the rear with a TracLock and a TruTrac for the front. My consideration now is 4.57 or 3.73 gears. I have a 60 with each. Most likely will go 3.73 because I have a set of Dana 30's to match. That's a 5% improvement on the 3.54 and the low-buck aspect appeals to my frugal nature. Mine has a T150 and Dana 20 so the T18/Dana 300 combo gives you a LOT more options in gears.

I find my Jeeps are in low range almost all the time, but my Jimmy with it's 6.55 first gear is hardly ever in low range for the type of offroading I do. But the 3:1 first and 2:1 low range of the '79 isn't even as low as 1st high range on the Jimmy. If I can score a T18/Dana 20 with the low 1st gear (not the '72-'75) it's getting swapped in ASAP. I've had my '79 about 6 months now. I went looking for a '76-'79 CJ-7 with the T18/D20 combo and a 6 cylinder as being the ideal Jeep for what I was looking. But the irony is I bought a CJ-5 T150 with a 360 and scads of other upgrades. C'est la vie!

 

If you're keeping the original straight 6, then a swap for a T18 would be ideal. If not, a SBC and either a good manual like a 465 or 420, or a 350 automatic. If you're thinking EFI, there are a lot of resources out there for the small block chevy, even available from salvage yards complete with PCM and wiring. And if you haven't been there yet, www.novak-adapt.com has a great knowledge section.

The Dana 300 is one of the best transfer cases out there, and a 4:1 low gear ratio swap would really improve your crawl ratio, if you're into off roading. If not, leave it stock, especially behind a relatively mild 258 6 cyl.

Axles aren't my strong point, but a Dana 44 is a great axle, and for mild trail use, would be ideal. Again, see the gearing section on www.novak-adapt.com and it can help. Have fun, and travel light!

 

Hello all,

Thank you so much for all the ideas and suggestions. I believe I am firm on fixing up the T5, however, I have a T18 on the way from a friend that will be a back up. This Jeep will be a daily driver in the warmer months (not too many of those in Portland) and used once a year at the Rubicon Trail (most likely once every two years). Winter driving will purely be to Mt. Hood in the snow and occasional beach runs.

The straight 6 is staying, I am adamant about that, sorry.
With the T18 needing every single gear replaced (it is really screwed up...badly) It will sit on the shelf and slowly rebuild as time passes.
The Dana 300.... I don't know if I should justify the $500 cost for the 4:1 gears. I am perfectly fine with spending $500 if it was a major improvement though...
The T5.... I am still looking for questions to the following:
-32 tooth vs 34 tooth cluster gear
-10 spline vs 14 spline input shaft
-29 tooth vs 27 tooth 3rd gear
-23 tooth vs 25 tooth 5th gear
-buying gears with or without needle bearings

The Axles: I am sticking with the Dana 44's as they are in my garage already and throwing in 4:10's with a disk brake conversion and YJ spring conversion on all four corners. I want a fully floating system going on.
I too agree the OX are the best choice.

Tires will be 33 unless I come across 34's that I like.

All in all, I am rebuilding my 1982 CJ7 Jamboree the same way as this 1979 CJ5 Silver Special Edition and both will be around for my great great grandkids to fight over.

@68BuickV6: I ran this Jeep all over knowing it was going to be torn down and rebuilt. It went everywhere and I loved everything about it except for me breaking the AMC20 and a few other select parts.

Again,
Thank you so much guys for all the answers.

 

Glad to hear you took it everywhere! It just kills me when people tear cars down and build them up and they're not what they wanted for whatever reason.

If you've taken it everywhere, you already know what works and doesn't.

Can't comment on gears, I know nothing about them.

Best of luck.

 

Put that 500$ on the t18, upgrading the dana 300 ain’t as good as putting a rebuilt t18. The 4:1 gear will weakest the dana 300, tooth are smaler and it will endure lot more stress than oem t-case. T18 is built strong if you compare it to the t5.

Also where those dana 44 were taken off? chevy, dodge, scout, ford?

 

Got it. The Dana 300 will remain stock. I will disassemble it, put it through a hot bath, powder coat it black and chrome, rebuild it, and put it in the Jeep. The T-5 is going to be picked up from the shop Friday to take it to my powder coat guy and it will be powder coated chrome. The T-18 will be powder coated chrome when I receive it, then sit on my shelf until I rebuild it. It may just be my spare or something I swap in once a year before the Rubicon Trail that way my T-5 gets all the highway wear and mild offroading and my T-18 gets the heavy stuff.

The Dana 44's are from a newer wrangler I believe. They will have 4.10 gears.

 

They won't fit under the jeep, the front end have the pumping on the driver side and our cj came with the pumpking on pass side. I read somewhere that you can flip the dana 300 using a clockring but i don't about turning it half a turn.

You may have wrangler rubicon axle so maybe a front coil spring conversion could be a easy mod to do because you already have all the necessery braket on the axle.

 

Yes they will. I had a machinist at work cut and weld them up pretty nicely. Thanks for looking out though.

Yes, my plan is to do coil springs in the front and maybe all around (don't know yet) but it is in the works.

 

All of your other plans sound great, but you will regret that T5 in the end. And on top of that, you will spend a TON of money going through it especially if you want to change gears.

 

Well,

This will make everyone happy but me. ;P

Just got word from the mechanic, my T-5 is shot to hell. The PO didn't tell me and I blindly bought it and sent it to the shop but here is the run down...
The cluster gear broke and spun around breaking every damn thing in the tranny and gouging the case. Then the PO re-assembled it and sent it on it's way to me. The mechanic is a good friend so I trust him as I have known him forever.... ****! I am now shopping for the T-18 and found a newly rebuilt with low gear for 900. I will have the mechanic check it out first but they say it is all new gears and bearings and gaskets..... one more time, ****! That damn PO.....

 

It bleeped it out

 

It's bleeped out because some of us don't appreciate that language. This isn't Pirate 4x4.

 

You got lucky IMO on the T5. Rather than going through it, getting it in the jeep and building the rest of the driveline around it to break and then have to be replaced, you get to do it right the first time!

 

Mike C,

I agree. The T18 cost about 1k rebuilt from R&P 4WD with a core charge applied and a bit knocked off for keeping the T5 parts. 400 in and 600 to go plus a core.
It should be done within a month but in the meantime, I am shopping for a Dana 300 core so I can have them rebuild one with 4:1 gears and I have an extra with stock gears. @68BuickV6, thanks. I am use to Pirate so I apologize.

BTW, I obtained a Muncie SM420, anybody interested? PM me or ccordova@cmm-measure.com.

 

I do too, I didn't mean to come off that strong.

 

It's cool, my mistake.