Low 4 grinding and High 4 sliping out at high torque??

[beejay42]

So, I got the BJ42 registered and on the road friday afternoon and took off down the Great Ocean Road a couple of hours later.
Took it for a play on some nice wet muddy tracks yesterday and encountered my first problem.

Everything was going beautifully- 2WD, High 4 and then Low 4...
then there was a fork in the road- straight up the steeper slippery slope, or around then up.
Of course, straight up it was

IIRC I was in Low 4- right at the top, just over the steepest bit, 4 wheels spinning and at about 2/3 noise- something happened, I think it popped out of 4 wheel and the back wheels spun (though I can't be sure)...
I wasn't quite sure what had happened, and trying to go forwards only spun the back. Wanting to take my first 4wheeling a little easy- I reversed down- re-engaged Low 4 and went up the other track 'around'.

Back on the trail and Low 4 was working fine again- but at high torque moments on steep hills I began to notice an occasional grinding noise- sort of like a fast ratcheting sound- when this would happen I would momentarily loose some rate of forward motion (front loosing torque- rear tires spinning?).
The then the trail got really steep, narrow and muddy, no where to turn around... ratcheting noise came more regualarly... not happy
I had to keep going up, so I put tried it in High 4- similar thing, the steeper and higher torque was the problem- and it would pop out of 4W into 2W (but this time without the ratcheting noise),
eventually I tried holding in down in High 4 with my hand and this kept it in 4 until I got to the top of the hill and found a small spot to turn around.
After that it was downhill and I got back home in mostly 2WD with occasional High 4.

No other problems at all, nothing wrong in 2wd, drove great on the highway.... etc.

So, I have been searching here, and I am reading about simple solutions- 'cutting the boot'... putting in new spring, or shimming with washers... bad engine mounts...?

I am a bit lost.
Trying to remain a little optimistic about it
Can anyone shed some light on this?

 

[Buckwheat]

Since it only happened in 4wd, & you were able to hold it in high 4wd, it can't be the hubs & must be in the transfer. It sounds to me like a bad shift fork or related. You can eyeball the shifter linkage for wear - not likely the cause but it should be checked. You will have to pull the trans cover to inspect thru the the top cover on the transfer, unless you're really good with a mirror.

 

[beejay42]

Thanks Buckwheat,
I'll go have a tinker now- if anyone has any images or explanations of what (or what wear) I am looking for that would be great. I'll get a few photos of whatever I can as well.

 

[beejay42]

heres the photos

High 2

High 4

Neutral

Low 4

freedom of movement left right in High 2

and freedom of movemont forward back in low 4

then there are the obvious things
X= a groove cut out of the metal,
Y= a section that is bent up vertically- is this normal?
Z= general looseness of the thing- that gap looks like it can be tightened with the nut on the end,

this bit of metal looks altered- and I am suprised at how it doesn't seem to be holding/guiding/connecting much of all in its correct position. Is this an attempt at the Low 2 mod? (it doesn't look like it to me as it won't go far enough over in 2w) Is this a bad adaptation of a non-standard part to this transfer case??
My rubber boot is fine, nice and soft.
Where are the springs in this whole set up I have been reading of?
Do I need to just replace that metal bracket/guide thing (what's the bloody things name??)

thanks for any help,
Hans.

 

[beejay42]

Shameless bump...;p

any observations on the bracket?

I am going to see what I can tighten up now, and take a drive.
Problem is testing the thing- gotta find somewhere really steep...

 

[KOOTENAY KRUZER]

My '79 BJ40 would pop out of 4 low into neutral backing down steep hills under compression braking. Instead of repairing the problem I was able to aquire an entire '82 BJ42 drivetrain (engine, transmission, tcase, rear axle & rear driveshaft) so I never did fix it, but when I did the swap I found the original tcase shift lever was out of rig enough that it rubbed against the edge of the opening in 4low and I guess the torque of backing down under compression twisted the drivetrain enough to pop it out of gear. Either that or it never engaged fully because of limited travel on the lever. I don't see anything in your pics to suggest that is your problem, but it is something to be aware of.

 

[beejay42]

thanks for that Wayne.

I tried tightening up that nut (or is it a bolt?) labled 'Z'- but I could only go maybe half a turn. Still plenty of wobble. I wonder- should this be tightened up with some washers?

I am not sure what to try next-
It seems to me that when in Low 4 the bracket should maintain some downward pressure on the shift lever rather than have all that free play? This might explain the occasional grinding as Low 4 could be partially changing out to low 2- but it doesn't really explain why High 4 would slip out into High 2 (because the bracket is not meant to hold it in place).


Damn its a bloody awkward place to try to work on...

I might try tomorrow giving Low 4 some torque on the steepest hill I can find while pulling the shifter down (as if the bracket was holding it in place).


Any ideas welcome.
What I would really like is if someone can tell me if my bracket looks right. I've been looking through the H41 manual but it is of little help to me.

 

[mudnyreye]

Check your motor mounts. My 40 had a bad right front. it would pop out of 4 low.

 

[beejay42]

Thanks mudnyreye, I'll check the mounts when the sun comes up again...

Aside from the bleeding obvious (cracked or loose or something) what does a bad engine mount look like?

Cheers,

 

[lc69hunter]

Had the same problem on my 69FJ.
Don't know how the BJ works, but on my 69 FJ,, I had a 4WD shift lever under the dash, which connected to the transfer case by way of 2 long rods. They had adjustments at both ends. That was how I fixed my problem. I lengthened the rod on the firewall, which ensured that the tranfer case was actually fully engaged.

 

[lcruzrlvr]

If the motor mount is broken, the fan will jump into the radiator and/or shroud. (of course, I am a gasser not a kerosene burner). I would begin there.

 

[beejay42]

It is very possible that the noise I was hearing was the fan hitting something- it was at least happening at the right speed for that to be the explanation. 'Grinding' was not exactly the best description for the noise- ratcheting comes a little closer. It is also very possible that I imagined any loss of power at the front wheels during the sound- if loss of power did occur it was certainly very minor and not a complete loss of power such as the slipping out from 4 to 2wd was.
I will check it out tomorrow and see if there are any wear points on the plastic fan.
And as described by some already, it would appear possible that a bad engine mount could cause both the fan hitting problem- and the slipping out of High 4 in into High 2.

Hopefully this is the solution.
Thanks all,

 

[Buckwheat]

Keep digging

X is nothing to worry about, Y is normal, Z can be corrected, if necessary, with a flat washer. I'd say the shifter & visible linkage are OK as is. The trucks with bad mounts must have a connection to the shifter linkage on the engine for it to move the case out of gear. Because your version is mounted to the trans/xfer assembly, I don't think you'll find any solace there, but look anyway. Block the wheels, idle the engine & have a friend let the clutch in & out, trans in gear. If a mount is broken, the engine will jump there & you'll see it. Don't forget the bell housing mounts. You needn't inspect the 2wd/4wd shifter, based on your description of the problem, but it is attached to the front output housing, easy to get to from underneath. I think the problem is the high/low shift fork, or related linkage, on the top, thru the cover, the hardest to get to, of course. You could have a worn or loose clamp where the linkage attaches outside the cover to the shift shaft. So after all else fails, pull your interior, remove the trans cover, & then get to the transfer top cover that way. Unless, like I said, you're real good with a mirror. You can get to the top cover from underneath but it's damn difficult to see inside the case & I'm not sure you can pull the shift fork out from there. You can get to the clamp on the shift shaft, though. Do it and enjoy it, because you're gonna do it anyway!

 

[Cruiserdrew]

The high-low shift forks get worn and lead to this. At lest that's what it was on mine, and cured by a new shift fork and t-case rebuild.

I agree to look for the obvious stuff first like a broken motor mount.

 

[Matty Awful]

Oxy time?

The selector on the Transfer case looks pretty close to the edge of the opening - if you're on a fairly bumpy track, the twist in the truck could be knocking the selector onto the edge of the opening and effectively knocking it back into 2wd. I had a similar problem when I switched to a split transfer case. It also made a ratching kind of sound when it wasn't engaged properly. I used an oxy & bent the selector back, havent had a problem since. Might be worth a try. Cheers

 

[beejay42]

Today, I checked the engine mounts and cannot find anything wrong with them,
the fan looks a little worn on some blade tips but was pretty inconclusive- also there is heaps of room between both the shroud and the radiator and the fan- I find it hard to believe that it would be moving that much?

I noticed that when shifting from 2 wheel to 4 wheel- pulling it all the way down felt like it set it in properly, but then with a little pressure it could shift out just a little to another position- just forward of full 4-Wheel... there was more than enough freedom of movement in Low 4 for it to fall out of the furtherest back 4 place... (this all sounds like a bad description, sorry)

So I set about pulling apart a few things to tighten up all the wobble and rattle in the system.
First thing, this loose bit 'Z'

needed a very exact washer diameter and thickness and so that it was tight but not bindingly restrictive when shifting across from High to Low. After trying a couple of steel ones with no success I made one up out of aluminium.

next up the 2 to 4 shift arm thing

the ball joint connection thing had a lot of free wobble- that square ball joint nut thing didn't fit very tight at all. It was also cracked.... or I cracked it thinking it was steel

Although it was made out of plastic, I decided to make a new one out of steel.
The donor,

after a bit more final shaping it was a snug fit (the plastic one wobbled at least a couple of mm)

I also offset the center of the hole to one side so as to better help the next process:
getting it so that when completely pulled back in Low 4 the shifter is supported and held in position by the bracket.

This is what it looked like yesterday pulling it back in Low 4

This is what it looked like this afternoon - it is up nice and snug and won't go back anymore.

This nice fit all occurred between three adjustments, the first washer, then the tighter ball joint nut thingy, then finally removing the bracket and filing out the bolt holes a little to allow it to move back a touch, and also giving it a little work over with a BFH.

It now shifts firmly and decisively with no wobble, no rattle, and when in Low 4 it is held by the bracket within the furtherest 4 wheel position- it cannot anymore fall out like it did to the bit just forward of that.

I took it for a little test run and shifting feels SOO MUCH nicer- however I won't know if it has worked until I try it in the same conditions (steep, slippery, high torqure, high revs...)

Fingers crossed it's done the trick.

Thanks for the advice everyone.