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amc 20 locker

S

sandsnowrock

sandsnowrock
Location
morgan
Ive got a 1980 cj-7 with the 151 4 cyl. motor and a 4 speed trans. i've a dana 30 with 4.88 gears in the front with a detroit tru-trac. its got an amc 20 with 4.88 gears and one piece axle shafts with an open diff in the rear. i run 33 12.50 tires now but may go to 34 10.50 or 33 9.50 when money allows. i would like to put a locker or limited slip in the rear but have been told that i would break axles. has anyone ever tried a similar set up? i want to keep the narrow axles because most of the trails i go on are 4-wheeler trails and if i was any wider i wouldn't fit. i doubt this jeep will ever see moab, mostly just mud and snow on dirt roads so it doesnt see as much abuse as most peoples rides. any advice or comments would be helpfull. thanks
 
Shawn

Shawn

Just Hanging Out
Location
Holly Day
sandsnowrock said:
Ive got a 1980 cj-7 with the 151 4 cyl. motor and a 4 speed trans. i've a dana 30 with 4.88 gears in the front with a detroit tru-trac. its got an amc 20 with 4.88 gears and one piece axle shafts with an open diff in the rear. i run 33 12.50 tires now but may go to 34 10.50 or 33 9.50 when money allows. i would like to put a locker or limited slip in the rear but have been told that i would break axles. has anyone ever tried a similar set up? i want to keep the narrow axles because most of the trails i go on are 4-wheeler trails and if i was any wider i wouldn't fit. i doubt this jeep will ever see moab, mostly just mud and snow on dirt roads so it doesnt see as much abuse as most peoples rides. any advice or comments would be helpfull. thanks
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If you have one piece shafts, I wouldn't worry about it. Get an ARB.
 
Rusted

Rusted

Let's Ride!
Supporting Member
Location
Sandy
I still have a AMC20 axle in my CJ with the 258 engine and 32" tires. I have a lock-right installed in mine. I did break a 1 piece axle before I had a locker, now I am locked at have 1 piece axles and I have been fine so far. I just feel like the axles are still a weak link on my jeep, so one day I will upgrade, but for now I just drive it and have fun. I worry more on moab rocks than I would dirt, snow, mud etc.
 
OCNORB

OCNORB

Well-Known Member
Supporting Member
Location
Alpine
sandsnowrock said:
Ive got a 1980 cj-7 with the 151 4 cyl. motor and a 4 speed trans. i've a dana 30 with 4.88 gears in the front with a detroit tru-trac. its got an amc 20 with 4.88 gears and one piece axle shafts with an open diff in the rear. i run 33 12.50 tires now but may go to 34 10.50 or 33 9.50 when money allows. i would like to put a locker or limited slip in the rear but have been told that i would break axles. has anyone ever tried a similar set up? i want to keep the narrow axles because most of the trails i go on are 4-wheeler trails and if i was any wider i wouldn't fit. i doubt this jeep will ever see moab, mostly just mud and snow on dirt roads so it doesnt see as much abuse as most peoples rides. any advice or comments would be helpfull. thanks
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:(

Just an FYI- It's a ticket if your caught on an ATV trail- requirements are that you are 52 inches wide or less and under 800 lbs.
 
M

MR.CJ-7

Your Realtor
Location
Woods Cross, UT
I wouldn't worry about it. I have the M20 with one piece shafts and the V-8. I'm not locked in the rear...yet, but even with my old 2 piece shafts and very heavy foot I never had a problem. As far as strength is concerned some say the M20 is comparable to a D44. The ring and pinion gears are about the same size. The weak point that comes to my mind is the small tube diameter on the housing. I wouldn't think twice about locking up the 20 with the one piece shafts. Especially since you've already spent the money on gears and shafts.
 
neagtea

neagtea

Well-Known Member
Supporting Member
Location
farmington
Detroit locker will do. If ya drive alot on the road stay away from the lockright. Trussing the hsg. is a good idea.
 
grinch

grinch

inner city redneck
Location
Salt Lake City
Ive run a narrow track 20 in my scrambler for years. It has superior one pice shafts, 4.56 gears, 35" tires, F.I. 258 motor, Lock rights (No i have never broken the locker). Any of the old timers on the board that have been wheeling with me can attest that I have never been easey on this axle or rig. Infact i have torn the knuckle off the front 44 on 2 different occasions and broke the front 44 so many times i cant count. I managed to break The modle 20 one time in 5 years and thats cuz it was so bound up that I think anything short of a 14 bolt would have snapped.
I did have to chang housing once because I bent it. Make sure you truss this housing it is a must!
Needless to say the buggie im building is getting this rear axle for a bit untill I can spring for a built narrowd 9" or somthing. Its a good axle with a bad rep.
 
buck55

buck55

Registered User
Location
Sandy, UT
I had to make a decision a while back to build up the M20 and live with it instead of investing in a new axle. I run the Warn one piece full floating kit w/ a Detroit with 4.56. I run 35's and have yet to even question my decision. I have no complaints about the setup and have addressed the strength concerns by trussing the axle, and have installed disc brakes. Go with a Detroit truss the tubes and have fun trying to break it.
 
S

sibeta

Registered User
Location
St. George
Dont waste your time with a limited slip....i had an auburn in my amc20 and i hated it. It only lasted 5 months in there before i got rid of it. Toss a lock rite in there and you will be happy with it.
 
S

sandsnowrock

sandsnowrock
Location
morgan
can anyone give me any advice or show me a picture of how you trussed your axle? just so i can see mabey what works before i screw around building something that aint quite right. and thanks to everyone who has put info on here for me. its good to hear i wasn't wasting my money when i started building this axle.
 
buck55

buck55

Registered User
Location
Sandy, UT
i had Outer limit do it for me since i am lacking a welder and tube bender. The took a tube and took it over the M20 pumkin and welded it at the location on top of the pumkin, and where the tube meets the axle, pretty easy, but huge gains. a hundred i think
 
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