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Discussion Starter · #1 ·
Heya all...I have an issue that has me stumped concerning the dana 300 I have in my 84 cj7.

I little history to help. I have the dana 300 behind a nv3550 (4L bell-housing and hydraulic clutch) driven by a 360 with the appropriate adapters, and it is clocked. The rear axles are 1 piece axles installed by collins bros when they replaced the busted ring gear years back.

The issue I am having is that I can put the jeep in 4l, 4h, or 2h and the rear wheels will turn, and I can even drive for a bit. However... I have come to the same stop sign ( about 1/4 mile from the house) and when trying to drive again the rear wheels will not drive the jeep. I can change to 4l and 4h and the front drive shaft will spin, but I get nothing on the rears. I have to lock the hubs and drive back with a front wheel drive jeep.

I am at a loss as to why the rears seem to work when the jeep is cold, but once it is driven a little the rears dont drive. I have checked the rear and can turn the driveshaft and spin the rear tires all day long. I dont get any grinding noise, vibrations, or anything...its just like the rear is in neutral. If I let out on the clutch I get no engine bog, no smell...nothing that would indicate anything other than the diff not spinning the rear driveshaft.

I have thought about converting to a twin stick, but I dont think that will fix the issue as im pretty sure the issue isnt how it is shifting.

As always, any help would be appreciated.
 

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Not the same issue but possibly related. Mine is twin sticked but I have yet to upgrade the pills. The rear very easily pops out of gear on any downhill engine braking scenario. I have to physically hold the rear stick in gear, front doesn't do it.

Have you checked to see if it's just popping into neutral or shifting in and out of 4 and back to 2?

Sent from my SM-A015A using Tapatalk
 

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Discussion Starter · #3 ·
When the jeep won't drive in 2h I shift into 4h and 4l. I can see the front drive shaft spinning as the cover is still off. I can't get the rears to spin. However...the next day (both times this has happened) I jacked up the rear, checked that I can spin the tires by spinning the rear drives haft, and then shifting the transfercase into 2h, start the jeep, and the rears will spin. Then I take it for a drive...and get left in the same spot.

The PO did make a custom plate that was connecting the two shift rods and it was very sloppy. I changed it out with the oem plate and pins...a lot less slop, but same issue.
 

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So when this happens, you are getting nothing out the rear of transfer case to the rear driveshaft, but front driveshaft will work.
Sounds like something gave up inside the transfer case, and when cold creates enough oil pressure to drive the rear wheels, almost like an automatic trans using oil pressure. When cold, push up on/chain off rear bumper to another vehicle/tree/etc, and see how much power you have to the rear wheels. Maybe not enough to even spin the tires?
 

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GO AHEAD

Tell me my addition is stupid and I never should have posted it.

Every CJ-5 prior (5 of 'em) except the present one (#6) did the same thing.

Your full story may not have been posted

All six, of mine had/ have a model 20

All but the last one, spun an axle in the hub.

Would not move in 2WD!

At 1st, several would grab and continue to move, but not long after, we went no where.

When I got number 6 in 1991, I went ahead and bought the Mosers (I figured I'd be prepared), they've been under the bed ever since.

There was no mention of one piece axles in the thread, so, of course, I brought it up myself.

Many times I see everybody jump to worst case right off the bat.

-----JEEPFELLER
 

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Somehow, I'm back to the log in mistake I made when this new stuff was implemented.

I WANT MY ORIGINAL MEMBERSHIP AND AVATAR BACK!

------JEEPFELLER
Me too, what happened to the old Mr JF?
 

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Logged out--logged in?

Maybe Mrs. Jeepfellers "drama book crap" is logging me back in to the other one?

----JEEPFELLER
 

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GO AHEAD

Tell me my addition is stupid and I never should have posted it.

Every CJ-5 prior (5 of 'em) except the present one (#6) did the same thing.

Your full story may not have been posted

All six, of mine had/ have a model 20

All but the last one, spun an axle in the hub.

Would not move in 2WD!

At 1st, several would grab and continue to move, but not long after, we went no where.

When I got number 6 in 1991, I went ahead and bought the Mosers (I figured I'd be prepared), they've been under the bed ever since.

There was no mention of one piece axles in the thread, so, of course, I brought it up myself.

Many times I see everybody jump to worst case right off the bat.

-----JEEPFELLER
He did mention having 1-piece rear axles (maybe it was edited after you saw it, though), so a spun factory axle hub wouldn't be the cause.

Could it be the shift rods are out of alignment, and the one for the rear drive is only partly engaging?
 

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Discussion Starter · #10 ·
Like Mister4x4 stated. I did mention i had one piece axles that were installed by collins bros when they replaced the rear end guts due to a broken ring gear.

I also thought the shifter rods may not be aligned correctly which is why I changed the po's shifter linkage setup back to oem with a used oem shifter plate and pins. The issue remains however. Whats odd to me is that I can put it in 2h and drive off, but once I get to a certain distance and stop it just does nothing.

As far as fluid pressure turning the rear axle...I've never seen that happen (not saying it is impossible) but the transfercase has no pump that I know of and I don't see how there would be enough pressure to turn the shaft.

The hunt continues.
 

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1984 Jeep CJ-7 Renegade
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Do you have access to look at the two shift rods sticking out of the front of the D300? Can you take a measurement?
When the D300 is in neutral, the rods will both protrude 2-3/16". I think one of your rods is popping out of position due to the twin stick setup you currently have.

Fluid Table Plastic bottle Liquid Gas
 

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He doesn't have twin sticks... is considering it to see if it corrects but I don't think it would.

I think it's a problem lots of twin sticks see. The fix is stronger detent springs. But since he's still single stick it's baffeling...

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The PO did make a custom plate that was connecting the two shift rods and it was very sloppy. I changed it out with the oem plate and pins...a lot less slop, but same issue.
My speculation is the PO had the same issue and tried to repair with his home made plate. I’m not familiar with the 300’s inneerds but definitely sounds like something not engaging or popping out.
You mention it’s always the same spot on your drive where it happens. Anything on the way a bump, pothole or something that will jar the linkage?
 

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Discussion Starter · #15 ·
Exheep - the road I go down is a pretty smooth concrete road in our subdivision. Its pretty smooth...what is strange about it is that im driving just fine until I get to the same stop sign...then it wont driving trying to pull away from the stop sign.
 

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I'm more familiar with a 20

The 300 has extra stuff

In the diagram I screen shot (from a parts list)

We ain't been riding pavement in 4x4 have we?

Possible worn stuff???

slots/ holes in the outside linkage?

worm Insert's on the fork tips (even missing?)?

Again mentioned---weak poppet ball springs

I feel sure that maybe one shaft "stops" to allow the other to move with the single shifter (like my 20)

Not knowing the 300---could one of the shafts (maybe if possible) be installed slightly (rolled) from it's correct clock position,

Which might not allow the ball to fully engage in it's slot (just throwing out stuff) Maybe that's impossible and every thing keys into place.

Have y'all looked at page "2D-37" in here https://oljeep.com/gw/82_tsm/Part 2 Section D.pdf

This is from the '82 manual---in the beginning reading some diagnosing is discussed as well as trouble shooting in a chart soon after that.

I grabbed this from a "Manual" within the link I show in my "signature"---more good stuff in that link.

-----JEEPFELLER
 

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