Perentie 4x4 transfer issues

[Phil B]

Hi all,

My 1988 Perentie FFR has several issues that seem related however I'm not sure if they are.

1. My transfer oil (RX Super) migrates into the gear box (1l every 2500km). This has not been an issue in the past, I just top up periodically.
2. On my way back from a recent outback trip my transfer jumped out of high range at a traffic light in Bathurst. I re-engaged high range and drove home to Sydney, no further issues until this weekend. Drove normally until halfway home after a 40km drive and jumped out again, flat road , under acceleration, 3rd gear. It did this 3 times in 5km. I got home and tried it in low range and it is jumping out of low range as well now. Has never done that before, and it has done a fair amount of low range work. The centre diff lock appears to be working normally.
3. After the same outback trip a hum / whine has developed on overrun in 3rd and 4th (over 70km/hr). This same hum is not present in low range, all gears.
4. It feels like the back lash in the drive train has increased since the trip.

I have read several posts related to the LT95A jumping out of gear (thanks Bearman and others) and will check the obvious ones (linkages, foam, lever touching the cover etc.)
I will be dropping the oil to look for colour soon and the question is apart from the obvious bits of metal what should I be looking for as far as colour goes?
I have checked the big nut behind the hand brake drum (intermediate shaft??) and that is tight.
I will also take the two cover plates off to check inside the transfer once I drain the oil. I've read to check for free play on the gears and look for any damage to the gears. How do I do this and what should I look for?
I read that the centre diff bolts have been know to work loose. How do I check them?
Anything else I can check?

I appreciate any advise in advance.

Regards,

Phil.

[Mick_Marsh]

Personally, I'd be using 20W50 oil in the gearbox/transfer case. I tried using a lower weight oil and wasn't happy with it.
Hearing your issues, I wonder if the lower weight oil caused my oil migration problem.

The oil migration problem is best fixed by replacing the seal. It has been discussed before in other threads on this problem. I'll see if I can find them.
I did a temporary work around about twenty years ago that is still in place. Replace the level plugs with barbs and run a pipe (rubber hose) between them.

[Phil B]

Drained the transfer case oil, dark brown colour, minute flexs of copper coloured metal, I assume brass? I have kept a sample to settle overnight. No ferrous fragments, I tested with a magnet.
Would that indicate thrust washers????
Does the centre diff have them as well??
Hope this helps the brains trust here give me more advise.

Thanks,

[Mick_Marsh]

Drained the transfer case oil, dark brown colour, minute flexs of copper coloured metal, I assume brass? I have kept a sample to settle overnight. No ferrous fragments, I tested with a magnet.
Would that indicate thrust washers????
Does the centre diff have them as well??
Hope this helps the brains trust here give me more advise.

Thanks,

Could be the thrust washers or the washers for the spider gears in the centre diff. They're the only bits I can think of but I've never had one of these gearboxes apart. Are the flecks of significant size? I usually get flecks of metal when I change the oil.

[Phil B]

Could be the thrust washers or the washers for the spider gears in the centre diff. They're the only bits I can think of but I've never had one of these gearboxes apart. Are the flecks of significant size? I usually get flecks of metal when I change the oil.

Thanks for the response Mick.
The fleck are very small and give the oil a copper tinge in sunlight. Definitely visable though.

Regards,

[Mick_Marsh]

Well, I get the same but only silver in the 100" and the Perentie but they are both TRB.
I don't do enough km in the 101s so I couldn't tell you what the oil was like.

You should also have a TRB in you Perentie so no thrust washers in the transfer case. That leaves the centre diff spider gears. I can't see how that would be causing the transfer case to be dropping out of gear.

[Bearman]

Phil it is going to be one of two things. Sounds like you have read previous threads on this issue so I think you will know what I am going to say. It will be either the lever fouling on the insulation under the gearstick boot or wear on the intermediate shaft itself which the hi and low range gears sit. Check the insulation bit first and if you are sure the lever is engaging the gears correctly then drop the sump off the transfer case and have a good look at the intermediate shaft gears. In particular check if the gears have any lineal movement. They should be firm and have no play in between them and also check the engaging dogs on both range gears. The teeth should be straight and not be tapered on the end that faces the selector gear (in the middle). Get someone the move the gear lever while you are under looking at it and see what is happening. Is it possible that the transfer may have run low on oil with your migration issue ? If so it is possible that the forks that move the selector gear may have worn from friction and now have a large gap which is preventing the forks from moving the selector far enough to fully engage the gear. It should be only be about .005mm gap between the rear selector fork and the gear face with the lever in neutral. The brassy look in the oil will be from the brass thrust washers behind the bevel pinions in the centre diff. Pretty normal but check for play in the centre diff while you are at it - you may have to reshim it. The centre diff bolts should be loctited and the only way to check is to take the rear output housing off and remove one of the bolts and check for loctite residue. Both the low range bolts and the ones that bolt the two halves together should be loctited. The migration issue can be fixed by loctiting the distance sleeve and output gear on the rear of the mainshaft. Also worth putting a welsh plug into the reverse gear shaft hole in the transfer as this is another known oil migration spot but this one transfers from the gearbox to the transfer case. Let us know what you find.

[Phil B]

Phil it is going to be one of two things. Sounds like you have read previous threads on this issue so I think you will know what I am going to say. It will be either the lever fouling on the insulation under the gearstick boot or wear on the intermediate shaft itself which the hi and low range gears sit. Check the insulation bit first and if you are sure the lever is engaging the gears correctly then drop the sump off the transfer case and have a good look at the intermediate shaft gears. In particular check if the gears have any lineal movement. They should be firm and have no play in between them and also check the engaging dogs on both range gears. The teeth should be straight and not be tapered on the end that faces the selector gear (in the middle). Get someone the move the gear lever while you are under looking at it and see what is happening. Is it possible that the transfer may have run low on oil with your migration issue ? If so it is possible that the forks that move the selector gear may have worn from friction and now have a large gap which is preventing the forks from moving the selector far enough to fully engage the gear. It should be only be about .005mm gap between the rear selector fork and the gear face with the lever in neutral. The brassy look in the oil will be from the brass thrust washers behind the bevel pinions in the centre diff. Pretty normal but check for play in the centre diff while you are at it - you may have to reshim it. The centre diff bolts should be loctited and the only way to check is to take the rear output housing off and remove one of the bolts and check for loctite residue. Both the low range bolts and the ones that bolt the two halves together should be loctited. The migration issue can be fixed by loctiting the distance sleeve and output gear on the rear of the mainshaft. Also worth putting a welsh plug into the reverse gear shaft hole in the transfer as this is another known oil migration spot but this one transfers from the gearbox to the transfer case. Let us know what you find.


Bearman,

Thanks for your very detailed response, it is really good and exactly what I needed.
I will inspect all the items you have mentioned this weekend and report back. Hopefully it is the lever fouling the insulation.
Yes it did run low on two occasions and required 750ml to refill. When I drained the oil this week it was about 100ml low.

I will let you know what I find.

Thanks again.

[Phil B]

Well, I get the same but only silver in the 100" and the Perentie but they are both TRB.
I don't do enough km in the 101s so I couldn't tell you what the oil was like.

You should also have a TRB in you Perentie so no thrust washers in the transfer case. That leaves the centre diff spider gears. I can't see how that would be causing the transfer case to be dropping out of gear.

Thanks for the response Mick,

I will investigate further this weekend and let you know what I find.
I have a detailed response from Bearman as well which I will investigate.

Regards,

[Phil B]

Phil it is going to be one of two things. Sounds like you have read previous threads on this issue so I think you will know what I am going to say. It will be either the lever fouling on the insulation under the gearstick boot or wear on the intermediate shaft itself which the hi and low range gears sit. Check the insulation bit first and if you are sure the lever is engaging the gears correctly then drop the sump off the transfer case and have a good look at the intermediate shaft gears. In particular check if the gears have any lineal movement. They should be firm and have no play in between them and also check the engaging dogs on both range gears. The teeth should be straight and not be tapered on the end that faces the selector gear (in the middle). Get someone the move the gear lever while you are under looking at it and see what is happening. Is it possible that the transfer may have run low on oil with your migration issue ? If so it is possible that the forks that move the selector gear may have worn from friction and now have a large gap which is preventing the forks from moving the selector far enough to fully engage the gear. It should be only be about .005mm gap between the rear selector fork and the gear face with the lever in neutral. The brassy look in the oil will be from the brass thrust washers behind the bevel pinions in the centre diff. Pretty normal but check for play in the centre diff while you are at it - you may have to reshim it. The centre diff bolts should be loctited and the only way to check is to take the rear output housing off and remove one of the bolts and check for loctite residue. Both the low range bolts and the ones that bolt the two halves together should be loctited. The migration issue can be fixed by loctiting the distance sleeve and output gear on the rear of the mainshaft. Also worth putting a welsh plug into the reverse gear shaft hole in the transfer as this is another known oil migration spot but this one transfers from the gearbox to the transfer case. Let us know what you find.

I have it in pieces and will have it check by a pro this week as I can’t see anything wrong. No play anywhere that I can see. I’ll report back

Bear man, the distance sleeve is free spinning as you suggested causing the oil migration. I am going to fix that while the box is open.
Which loctite should I use in between the shaft and sleeve?
Also which loctite on the diff bolts ?
Thanks again
Phil

[PhilipA]

I did a temporary work around about twenty years ago that is still in place. Replace the level plugs with barbs and run a pipe (rubber hose) between them.
I did the same and I think it is still under the house.
The only addition I would suggest is to solder the opening of the nipple , then drill with a small jewelers drill, maybe 0.5 mm or smaller.
That way the gearbox oil does not run into the transfer on steep hills.

[Bearman]

I have it in pieces and will have it check by a pro this week as I can’t see anything wrong. No play anywhere that I can see. I’ll report back

Bear man, the distance sleeve is free spinning as you suggested causing the oil migration. I am going to fix that while the box is open.
Which loctite should I use in between the shaft and sleeve?
Also which loctite on the diff bolts ?
Thanks again
Phil

243 is fine but make sure you clean and prime everything before applying the Loctite. Also before you pull the gear off the end of the mainshaft to loctite it and the distance sleeve it is VERY important to put the gearbox in 3rd gear first, otherwise you will have trouble getting it all back together.

[Phil B]

243 is fine but make sure you clean and prime everything before applying the Loctite. Also before you pull the gear off the end of the mainshaft to loctite it and the distance sleeve it is VERY important to put the gearbox in 3rd gear first, otherwise you will have trouble getting it all back together.

Thanks Brian, will do.

[Phil B]

A report back on the transfer issues:

The transfer case intermediate shaft and its gears etc is now at KLR and they report that the main bearings in the cluster on the shaft have started to wear causing the noise on overrun.
They believe that the pre load or end float (too technical for me!!) may not have been correctly set up when the box was re furbished by the ADF years ago. The additional end float caused by the bearing wear has now caused the jumping out of high range.
The spacer on the main gear box output shaft is not loctited as Brian predicted and is causing the migration.
The copper coloured oil is from worn diff shims, possibly caused by not using the diff lock enough on my last trip.

The intermediate shaft, gears and bolt and the main gear and shaft are thankfully all servicable.

KLR are rebuilding the intermediate shaft cluster as well as the CDL and I will very carefully remove the main shaft gear and loctite the spacer this weekend before replacing all the parts.

I am quite relieved that I now know what has caused the issues and that essentially the transfer box will now be completely refurbished and hopefully last for years to come.

By the way I did check for interference to the lever and linkages and found that the foam was missing and the linkages need some oil but are otherwise OK.

Thanks again for everyones help.

Regards,

[Mick_Marsh]

Thanks for the report back, Phil.

[Phil B]

More news on the transfer box

On closer inspection the intermediate gears are pitted (suspect it stood for a while with the ADF when it was inoperable).
Replaced them (good used) and the gear box output gear (new),diff shims, bearings and main intermediate bolt.
All put back together by KLR (thanks for the outstanding service Brad).
I re-installed it all yesterday and left it overnight for the loctite on the spacer and main gear to go off (overkill I know but it’s cold!!)
Drove her this morning and all appears well!
Very pleased. Took about 6 hrs ( no ramp or hoist at home) and about $1600 all up.
Difficulty level medium (for me) except the main shaft spacer, gear and circlip which is a PITA.
No special tools required.
Phil