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Transfer Box Won't Turn

You've lost me a little, before I go spouting off anymore have you got a photo of the offending article, me and a mate had a run in with some transfer boxes(LT230s) a few weeks ago and ended up probably further back down the information line than when we started, but with all the best will in the world I don't remember any shimming going on in the rear output shaft or speedo drives for that matter, the bearing takes it up I'm sure, send some photos, there's some clever chaps on here who know their stuff they might be able to help aswell
 
stevebus said:
You've lost me a little, before I go spouting off anymore have you got a photo of the offending article, me and a mate had a run in with some transfer boxes(LT230s) a few weeks ago and ended up probably further back down the information line than when we started, but with all the best will in the world I don't remember any shimming going on in the rear output shaft or speedo drives for that matter, the bearing takes it up I'm sure, send some photos, there's some clever chaps on here who know their stuff they might be able to help aswell
Click to expand...
Here's a pic of the back of the transfer case without the handbrake components. The housing at the back contains the speedo drive and output coupler seal. The housing also serves as backstop for the rear shaft bearing outer race so shimmimg this housing adjusts the bearing clearances. You can see the bearing poking out of the case a bit in the second pic - the shims adjust the position of that bearing.
20240226_230313.jpg

20231228_035056.jpg

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Here's a section view:
Screenshot_20240429_163220_Adobe Acrobat.jpg
 
mbalpha said:
It’s a series box on a 1982 “88.

The output shaft had a huge amount of friction and even with the output nut not done up it took two hands on the drum to turn it. No chance you could have turned it by hand just by grabbing the output shaft.

I took the shoes and back plate off and still the same, very hard to turn, regardless of being in hi, low or neutral.

With the speedo housing off everything freed up. I can see the speedo worm gear is a bit chewed. I’ve not been in here before so it is very possible the previous owner has put something back incorrectly.

I too am wondering what the difference will be when I get the shim clearance right and tighten everything back up as I can’t see how the speedo housing alters the distance between the output flange shoulder that rests on the Speedo worm that itself rests on the bearing. It’s like there is too much length in the shaft and when you tighten everything up the main output nut goes on the shaft a long way and then everything binds up.

Sorry if I’m not describing it well enough but it’s what I see in front of me. I’ve done nothing more than release the speedo housing and that’s what freed everything up. I’m beginning to see why the nut was so loose when I first took it apart as I suspect the previous owner just gave up and tightened it as much as they dared to and left it at that.
Click to expand...
Hmmm... interesting. Well it'd be good to get that maladjusted lower shaft preload fixed up properly for starters. I'm still curious about why tightening the output nut causes binding but perhaps that'll go away once the bearings are sorted. Pretty crazy that it drove around like this presumably without issue.
 
@mbalpha
If you are taking the transfer case off to set up the pre load on the drive shaft it will be worth removing the front output shaft casing to ensure that over tightening the preload has not damaged the circlip that holds the front bearing cone section in place has not been damaged.
 
The shims are set to a prelaod and the shaft will still turn quite easily so for it to be stiff I think something else is wrong. Can you feel any backlash on the stiff shaft? Is it free for a fraction before it gets stiff? I'm trying to work out whether the shaft itself is stiff or whether something connected to it is stiff. My feeling is that something has been assembled wrong but I can't work out where to look first. With the transfer box in neutral there's not much left.
 
SeriesG said:
Hmmm... interesting. Well it'd be good to get that maladjusted lower shaft preload fixed up properly for starters. I'm still curious about why tightening the output nut causes binding but perhaps that'll go away once the bearings are sorted. Pretty crazy that it drove around like this presumably without issue.
Click to expand...
Thanks for the cross section diagram. That helps me explain it to my son (14) who’s keen to learn how it all works. Yes, it was driving and relatively quiet but a bit leaky. The handbrake was working well too but totally full of oil when I opened it up but the it kept on driving.

I’ve ordered some more shims today and a new worm gear so I can eliminate that as being an issue.

Couple of pictures here showing the bearing that appears to be fine as no slop in it at all.
 

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The speedo gear in the housing has a cut away and if put in 180 degrees out, it may chew the gear. You can see it looking in the housing.
I did my S1 box today. Shims needed were .110 inches (2.8mm) 8 or 9 shims were used. New bearings. The Old shims were cleaned up on my buffing wheel.
Which way round was the damage gear fitted against the bearing?
If you set housing as per manual, no shims fitted and tighten nuts evenly until preload is between 2 and 4 lbs Pull. Then measure gap in pic 3 with feeler gauges.
Assemble shims to get the same measurement and you will get pretty close.
I used the output shaft for the string to start with, then moved it to the Low gear wheel selector grove to double check the preload. It made no difference if fitted on either.
 

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whitehillbilly64 said:
The speedo gear in the housing has a cut away and if put in 180 degrees out, it may chew the gear. You can see it looking in the housing.
I did my S1 box today. Shims needed were .110 inches (2.8mm) 8 or 9 shims were used. New bearings. The Old shims were cleaned up on my buffing wheel.
Which way round was the damage gear fitted against the bearing?
If you set housing as per manual, no shims fitted and tighten nuts evenly until preload is between 2 and 4 lbs Pull. Then measure gap in pic 3 with feeler gauges.
Assemble shims to get the same measurement and you will get pretty close.
I used the output shaft for the string to start with, then moved it to the Low gear wheel selector grove to double check the preload. It made no difference if fitted on either.
Click to expand...
Thanks for all the pictures. Very helpful. 110 thou is a fair amount, I’m currently at 68 thou and have just ordered another 70 thou of shims.

It maybe a silly question but is there a way to set the preload when the transfer box is attached to the gearbox? I’ve seen a method where you fit the shims first the trial fit the housing and feel by hand if the shaft is grabbing or not and then once it’s just free add another 5 thou and tighten everything up. I’ve had the transfer box in and out so many times now I’m running out of gaskets. 😬
 
mbalpha said:
Watching the video it is clear I have to take it all out again to do the pre-load...oh joy.
Click to expand...
Can you clean all the grease away from the output shaft and bearing it might just be grease but too me they look blued as if they have been heating up.
Looking at your photo in post 29.
If you take the intermediate gear out you can do the preload in situ.
 
You can do the output shaft pre-load in situe. The pre-load for the correct torue is about 7-10 thou and the torque range spec is quite wide so its not difficult. You can convert the string pull to torque. I did and used a 1/4 drive torque wrench, that way i could leave the base cover on. I think the aim is to get just enough pre-load that there's no play when the box is hot.
 
Sorry for the radio silence for a few days - scouting activities got in the way.

I will get some better pictures. I'm hoping it's just some bad light reflections on the bearings.

More gaskets arriving today along with a new worm gear to eliminate the burred and pitted spiral teeth on the old one.

If I convert the string pull method to torque on the output shaft do I still need to remove the intermediate gear? I have a 1/4 inch torque wrench so I can get down to the low torque setting quite accurately.

I'll get some cleaner pictures posted up later today. Thanks.
 
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