LT230 Lubrication Mods

[Bush65]

I found this modification for LT230's on the web site for Ashcroft Transmissions. It was included with the instructions for installing their crawler gears into an LT230 transfer case. The page has gone now, along with the crawler gears, which were not as popular as their underdrive add-on.

The final drive gears for high and low range, do not have rolling bearings. They employ hardened steel, plain bearings. This is possible because the driven gear (for the range selected) rotates with the centre differential shaft. The other (non-driven) gear does rotate, relative to the centre differential shaft, but the radial load is small.

Because of backlash between the teeth of the selector sleeve, small movements do occur between the driven gear and centre differential shaft. Good lubrication between the mating surfaces is necessary to avoid wear and fretting corrosion.

The modifications detailed here, improve oil flow to the high and low range, final drive gears.

The LT230 gear case, the rear output shaft and the sleeve inside the high range final drive gear must be stripped out for the modifications.

The modifications to the gear case are described first.

'Figure 1' (below) is a cross section drawing through the final drive gear and centre differential assembly.

There are two oil holes through the rear of the case where the rear output/speedo housing fits. The 6.5 mm hole at the 6 o'clock position, should be plugged by tapping the hole to M8 (see 'Figure 2' below) and fitting a grub screw. The 8.5 mm hole at the 12 o'clock position, should be drilled out to 12 mm and angled upward at approx 45 degrees (see 'Figure 3' below).

The enlarged upper hole feeds more oil into the rear housing, and by plugging the lower hole, the oil level is increased so it will return to the main case through the final drive gear and centre differential assembly.

Now that more oil can be fed to the rear housing, we need to modify the rear output shaft to create a gap for oil to flow between the output shaft and the hollow centre differential shaft (see 'Figure 4', '5' and '6' below).

'Figure 7' shows the modified rear output shaft and the new dimensions of the modified features. The outside diameter and width of the shoulder are reduced. The material is removed from the front side (right side in the figures below) of the shoulder and blended into the fillet radius.

'Figure 8' and '9' show the modifications to the sleeve that fits inside the high range final drive gear. The diameter of the shoulder is reduced and a flat machined on one side.

That completes the modifications to the components of the lT230.

The patches that look like stain marks on the centre differential shaft in 'Figure 5' and the sleeve in 'Figure 9' are light fretting corrosion.

The straight cut (spur) gear in these photographs is a low range crawler gear from Max-drive Engineering. The standard low range gear has helical teeth.

Be careful when assembling the final drive gears on the centre differential shaft. The selector hub (not shown in the photographs) for late LT230's, has a chamfer on one side of the bore, be sure to assemble the selector hub with the chamfer towards the low range gear or the high gear will bind.

[Bush65]

Further Figures for above post.

[DirtyDawg]

Cheers Bushy..good mod for the next time I have the tranny out;)

[rick130]

Nice post, thanks John.
Hopefully this will be archived by the mods.

Another t/case mod that can be done involves replacing the four intermediate thrust washers which are 3mm thick with Maxi-Drive ones which vary in thickness between 4mm to 2mm to move the high range gear closer to the slider. This enables an extra 1mm of dog engagement.
1mm may not sound like much, but it's a 25% increase in dog engagement and can prevent the thing jumping out of high range

[Disco_owner]

John;

Would this be a DIY job do you reckon, I'd like to have a Crack at installing crawler Gears, but does it require any special tools?

[Bush65]

John;

Would this be a DIY job do you reckon, I'd like to have a Crack at installing crawler Gears, but does it require any special tools?
My post was not about installing crawler gears, nor are these mods necessary if installing crawler gears.

No special tools are required to install Maxi-drive crawler gears.

For clearance from the larger diameter of the final drive gear, it is necessary to grind away some material from some bosses/webs inside the case and from one side of the shaft for the selector fork.

Some LT230's need another drain hole drilled and tapped to relocate the magnetic drain plug away from the low range final drive gear.

A lathe is required to carry out the lubrication mods detailed in the above posts. The shaft and sleeve are hardened and difficult to machine with normal tools. Perhaps some ceramic tips would be ok. In my case an angle grinder was used while the parts were spun in a lathe. A 1mm disc was used to cut the flat on the sleeve.

[Bush65]

...
Another t/case mod that can be done involves replacing the four intermediate thrust washers which are 3mm thick with Maxi-Drive ones which vary in thickness between 4mm to 2mm to move the high range gear closer to the slider. This enables an extra 1mm of dog engagement.
1mm may not sound like much, but it's a 25% increase in dog engagement and can prevent the thing jumping out of high range
That mod sound like it would be for an LT95 transfer case?

[rick130]

That mod sound like it would be for an LT95 transfer case?

could be.
It's in my Maxi catalogue lumped in with all the rest of the LT230 stuff so just assumed.....:confused:

I've only been into my LT230 to do the input shaft seal and inter shaft O ring.

[Rangier Rover]

I have dug this thread up rather than start another.

My LT230 has dropped the rear bearing on the intermediate shaft from what appears to be oil starvation.

http://www.aulro.com/afvb/technical-chatter/104043-lt85-santana-5-speed-lt230-2.html#post1253641

I'll have another search around for any more ideas.

[uninformed]

Bump for a great thread. John, do you have any details on cross drilling the imput gear for the early lt230s that dont have it?

[Ancient Mariner]

www.aulro.com/afvb/.../167743-isuzu-engine-swops-dummies.html

On page 2 there is a couple of pics.Just make sure to set it up square so you drill into the root diam of the spline. tungsten drill .ridjid and slow speed constant pressure +;) good luck

[rick130]

Bump for a great thread. John, do you have any details on cross drilling the imput gear for the early lt230s that dont have it?

Serg, the latter style gears also have the splines broached deeper along the shaft too for more engagement.
I think Matt/rovercare and maybe Steve has drilled gears, I'm guessing you'd need a cobalt bit and lots of coolant, or EDM it.

Steve/RoverRescue has a thread on it.
On the phone ATM so not so easy to search.

[uninformed]

www.aulro.com/afvb/.../167743-isuzu-engine-swops-dummies.html

On page 2 there is a couple of pics.Just make sure to set it up square so you drill into the root diam of the spline. tungsten drill .ridjid and slow speed constant pressure +;) good luck

Just to clarify, the spline is internal, and we want the centre of the drill hole to be centre of the root dis, or female portion of the spline. This would also be the thinest part of the body at that point?

What is your preference of drill bit, Tungsten or cobalt?

What dia hole?

[Vern]

Serg, the latter style gears also have the splines broached deeper along the shaft too for more engagement.
I think Matt/rovercare and maybe Steve has drilled gears, I'm guessing you'd need a cobalt bit and lots of coolant, or EDM it.

Steve/RoverRescue has a thread on it.
On the phone ATM so not so easy to search.

Rick, that would have been myself, Steve, and mike_ie who have drilled them, mike and I used a cobalt drill bit and trefolex and drilled it in the drill press, drilled rather easy once I found the correct bit. I'll have a look and see if I can find what brand it is.

[Vern]

OK, this is what is written on the drill bit case.

Allround- Bohrer.

Beton. Mauerwerk. Eisen. Glass. Keramik. Hotz.

Its a blue and white case, drill bits are black with a tungsten carbide looking tip.
Hope this helps:)

[Ancient Mariner]

Just to clarify, the spline is internal, and we want the centre of the drill hole to be centre of the root dis, or female portion of the spline. This would also be the thinest part of the body at that point?

What is your preference of drill bit, Tungsten or cobalt?

What dia hole?
Just had a look at a original 10 mm drilled about 50-50 thru the spline.The only reason I suggested the female part was for an even load on the bit when breaking thru.I would have thought cobalt would not cut the mustard but being LR anything is possible

Noel

[Bush65]

A stellite drill will drill through the gear like it was made of cheese - they are typically used for drilling high speed steel, such as drilling out broken thread taps.

However they are very expensive, and the heat they generate may adversely affect the gear.

If others have had success with cobalt drills, I would try them.

[uninformed]

Thanks for the replys guys. I have an older lt230 that im going to have a go at going through.

Vern, that bit, I believe is made by a company called Artu. German. I saw these over 15 years ago at the timber and wooking with wood shows. Being sold by a guy with head mic and cheesy sails pitch. I thought they were gimmickie rubbish. I have learnt that while they dont replace some of the much more expensive professional equipment, they are pretty good.

Is it just 4 holes equally spaced around the dis? Would a pilot hole be advisable?

[Vern]

Yeah Artu is it, I just drilled a hole straight through with this.

[uninformed]

Started to pull my LT230 down, low and behold the input gear has already been drilled by the previous owner..........I should not have been suprised :)

If this case and its parts are worth rebuilding, I am hoping to have a go at the mods in this thread......... :eek:

[Vern]

Is yours a 1:1? The gear for the 1:1 's are the only one you can't buy cross drilled, all other ratio's you can.

[uninformed]

Nope, 1.4 high range. From this link on Ashcrofts site:

Ashcroft Transmissions - Input gear (http://www.ashcroft-transmissions.co.uk/index.php?act=viewProd&productId=8)

it appears it is not ratio dependant, but year of build. The case I have is an early LT230T (suffix B ) case, so the input gear is not available cross drilled. (As I read it)

[Vern]

True, but 1:1 (1:1003) which is a 14D or 26D fits in the A/B category that's why I asked, so all 1:1 ratio transfer cases you can not get the cross drilled gear for, therefore having to drill your own. Trust me, I found out the hard way:(

[uninformed]

Vern, not sure if im not understanding you correctly, but the Suffix is the last letter in the serial number on the t/case. The first 2 numbers and very next letter are the designation for what vehicle and ratio it was fitted with from the factory.

So any ratio that is in an A or B suffix case(serial number ending in either A or B ) will not have an input gear that can be bought new cross drilled.

The reason I say this is because of your first statement saying any other ratio than 1.1 can be had in cross drilled. This is not entirely true and a little confusing.

The input gear basicaly only comes in 2 tooth counts, 26 or 28. But there are many variables to them that makes the ability to just use either in any case not so. As in the 1.4 ratio in my B suffix case, this imput gear is not available cross drilled.

So are you saying that either the 14D or 26D 1.003 ratios come in boxes with later suffix than B?

[Vern]

Sorry ignore that first post, I just re read what I typed, should have said all 1:1 ratio transcases you can't get a cross drilled gear for.

[uninformed]

Vern, I just sent some emails back and forth with Dave Ashcroft. He is saying the 1.003 high range was also available in the "C" suffix boxes. These have a cross drilled input gear available. So the way I am understanding it at this stage, regarding the input gear, is, it is not dependant on ratio at all, but rather the build date/suffix.

This does not mean you can get the input gear for the 1.003 high range set that was used in a "C" suffix box and install it in a 1.003 "A" or "B" suffix box. You have to use compatable gear sets, as Bush65 pointed out in a couple of Isuzurovers threads:

http://www.aulro.com/afvb/members-rides/99871-isuzu-county-tourer-17.html

http://www.aulro.com/afvb/showthread.php?p=1959589#post1959589

[Vern]

109093109094i am about to do these oil mods to my lt230 and was wondering what the purpose of the flat machined onto the sleeve is for? And is it supposed to be fixed into a certain position on assembley or just spin around at it own accord?

[Vern]

Well guess thats in.the to hard basket! Will just do as instructed😊