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[MK1]

Here we go.....

Firstly, can anyone give me an idea of the standard diff ratios of a 79 CJ7 258?

Secondly, how strong is the D30? For bigger tyres (33s or possibly 35s) does it need anything upgrading, other than a re-gear?

[isle of man]

to make a dana30 strong enough for 35" tyres would cost a "fn" fortune you would be better to replace with a stronger less expensive axle d60 perhaps.



peter henry

[Mick O]

I think Bubba ran 35's on a D30 in the beast.

And that was awesome

[MK1]

Calling the big man in the hat, are you out there?

[king cj]

the 30 will hold up to 35s with chrom moly shafts and larger u joints as long as you dont lock it. standard gearing should be 4.10 for a 79 but you might want to check , there should be a tag on the diff cover but some times it goes missing

[Bubba]

d60  lets not go trippin over trendy for a mo .yup i ran 35s on a d30 no regear no sexy shafts no nuthin first i ran a meaty 258 then junked that for a v8 i broke 1uj doin an almost inposible recovery and that was it and i ran that truck plenty hard i had planned to fit  a truss to prevent bending the axel tubes but that was all
in short mr barrs lift it and and fit ya 33s or 35s and try it there are several cjs in the club runnin 33s no problems and no regear [darkrider spidy shawn of the dead]  sure shafts are a good idea for front and rear as cing cj sez

[Bubba]

forgot to say axel ratio i done rekon you got 3.54  tis the standard ratio for 76 to 79 cjs 4.10 was an option but not that common jack up ya jeep and mark the prop turn the rear wheel one complete turn and watch the prop turn if it goes round 3 and half turns you have 3.54s if it goes round 4times woohoo you got 4.10s

[king cj]

i agree run it till it brakes if it doesnt great when i locked mine i broke u joint like no tommorow so i put ox ujoints in and chrom molys and never broke another,then the other weekend i blew the ring and pinion. i wasnt driveing it nice and i have a 360 v8 im now swaping in bigger axles but also putting bigger tyres on. in short i would see what happens.

[isle of man]

for me i believe in over engineering why do half-a-job and regret it.....then pay twice for the same up grade.
i have ripped off the d30 front axle from a tj when the lower arm bracket snapped also tore r&p and blown a shaft and bent the axle tube....hence i'm possibly over caucious but with my history do you blame me?


peter henry

[Bubba]

i know i am gonna burn for this but the cj is tougher than a tj you wont never tear the axel off and i have a feeling that the tube is thiner on tjs than cjs and the tj dana44 uses d30tubes so they can bend

[isle of man]

what i have now is a tera hp50 with 1/2 tubes and d60 knuckle's 35 spline shafts and ctm u joints with clayton brackets on the front of my tj...you don't want to know the cost!!!! but for me this was the ultimate up-grade will let you know how i get on......
i still think the d60 would be a good choice up-grade for the money....just my thoughts.


peter henry

[Bubba]

wow i want to drool over that that sounds bomb proof there is  some sexy axels out there at the mo

[Anonymous]

Hi Mark,

I am not the best tech head on the site by far, but Bubba is right I do run 33's and i have not has yet regeared the axle.Never had any major problems.Just put the dam 33's on and see want happens.