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1978 cj 7 questions

1K views 22 replies 6 participants last post by  Hbryant123 
#1 ·
I may possibly buy a 1978 cj7 with a 304 v8 and 3 speed automatic transmission, it was running two years ago and i was told the engine was just tired. This jeeps main purposes for me will be to pull my boat a few miles to the lake and do some light to medium offroading. I am dead set on getting a cj7. It has the levi blue interior also. What all should ik about this beast? i was reading it has awd? does that stay locked in all the time? thanks, any advice or tips is appreciated
 
#3 ·
I just built a 77 cj7 with the auto and quadratrac transfer case, you may have a part time conversion in the transfer case in which case you would have the manual locking hubs, also it has the offset AMC 20 rear end, so if you change to one-piece axles you have to keep that in mind
 
#9 ·
I've forgotten to take mine out of low range after a day of four wheeling and figured it out once I hit the road. It really starts screaming at any speed. It felt like the tranny was stuck in first gear.
With the full time four wheel drive of the quadratrac it won't hurt to run low range on the pavement.
But running it at any sustained speed (30 mph or so) may not be good for it. The low range reduction gets it's oil from splashing from the main case, it may not get enough for high speed lubrication.
That's just pure speculation and not based on any first hand experience.....:cheers2:
 
#10 ·
Yeah top speed in low range will be 20 to 30 mph. But that's mostly irrelevant - if you can travel that fast, you should probably be in high range. Low range is for crawling along, over broken ground ... big rocks and such.

The Quadratrac has the low reange lever, and it has the "emergency drive" (E-drive) control in the glove box. This is a vacuum operated shifter that switches between full-time and conventional 4 wheel drive. Read the article on the Jubilee Jeeps site. There's a link in the thread that I linked to.
 
#12 ·
Hbryant123 said:
Yes i did read that article and found it to be very helpful! is the three speed tranny tough? i read 1978 was the last year for the heavy duty one. When put in the emergency 4x4 does it truly lock all the wheels in? thanks everyone
The TH400 is about as tough as they come.
In normal mode the transfer case will allow some slippage front to rear as needed for driving on the road. If it didn't, something would bind and break due to the speed difference between the front and rear tires.
E-drive locks the center differential so there is no slippage front to rear.
Without some type of locker, you will still only have one front and one rear wheel driving.

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#14 ·
Hbryant123 said:
So if i get hung up and lock it in emergency 4x4 will it actually be better than normal 4x4? or does it just keep the front wheels from turning more than the rear?
If you we're to get stuck and have just the front or rear wheels spinning it would be very hard on the center differential. It is steel on steel,and any slippage is wearing it out. Locking it will prevent that slippage.
I have mine locked in any time I go off roading.

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#17 ·
The ultimate would be selectable lockers front and rear. That would keep the pleasant and predictable characteristics of open differentials on the street and in snow and ice, plus superior trail performance.

Conventional lockers can be difficult to manage (unpredictable vectoring) in snow and ice.
 
#19 ·
The AMC V8s are roughly equivalent to the other V8s of the era. They can be very long lived if well maintained.

You have to take the differentials apart and install the locker, and set up the gears. Installing differential gears is likely the most advanced mechanical job you can attempt. Needs special tools too. Most amateur mechanics would pay somebody to do it.
 
#21 ·
Glad to see another Levi edition cj here.
I have a 1978 Cj7 Levi, green paint with the Tan Levi interior. Its a 304 jeep but the previous owner swapped the v8 for a 258/6 cyl., still has the TH400.

Depends on your climate. I see your in Indiana so I would guess its cold. Go with a standard 10-30 or10-40. When it starts to warm up a bit go with 15-40 like used in diesels.
 
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