Thread: Isuzu MSA Gearbox to LT230

Spline on a standard flange is shorter than that. As i said, if your concerned then get him to cross drill it

Originally Posted by 123rover50

Thought I would drop in.

How do you run the 3rd axle drive with the 230?
Diana saw my rig at the auctions earlier.

I am running the 5G with the LT 95 T,box . Lately the gear change has been getting stiff. I pulled the top off the 5G and the main gearset has moved forwards by about 5mm.
I suspect the nut has come loose but have yet to inspect it.
The way we built it the whole G,box and T,box has to come out as one then the T,box guts removed to get to the fixings that hold the boxes to the spacer housing.
I was thinking that if the housing was cut in half and two more flanges welded in with the bolts on the outside , the T,box could be unbolted leaving the G,box in place. The splined adapter would then slide off for removal.

Keith

Finally got it stripped. Standing on its nose and working down.
The nut had come loose all right. Looks like I had only used one of the indents to deform into.
Interesting, of the MSA 5G boxes I have , One has no indent in the end of the shaft, One has one, and Two have two indents to stake the nut into. The box I will replace this one with has two indents or grooves but even with that ,the nut has stared to unwind so this must be a problem. I know nothing about the history of this box but hope its OK. I figure the box I was driving with the loose nut could have been wearing out the synchro cones so will swap it.
Any hints on what to look for inspecting through the box top?

Originally Posted by Lotz-A-Landies

Hi Guys
I don't want to turn this into a slinging match.

I understand the issues of a dry joint and the original uni-joint flange. Why do you think Isuzu sell replacement flanges? Because of wear in the spline in a situation where replacement is a relatively quick repair. In our cases the adapter shafts are a small run orphan parts, where you have to uncouple the LT230 from the gearbox and then remove the adapter shaft from the mainshaft to lubricate and then reverse the process. I would prefer a lubricated shaft or a quick lube process.

Re the Getrag adapter, there are many reports of failure with dry joints, some with only a little over 20K on the clock. It is why Ashcrofts have made their lube kit. Yes the Isuzu adapter spline is about twice as long and has larger teeth on the spline compared to the MT82 although the MT82 adapter has a larger diameter reducing some of the difference.

Without the shaft running in oil or something like the Ashcrofts kit, I would prefer the idea of the cross drilled adapter shaft with a balanced pair of grease nipples, maybe with a corresponding greaseway/groove around the mainshaft and a hole in the adaptor housing so I can grease the shaft in a lubrication schedule every 20K-50K or something.

Its just something so we can maintain our toys in the long term. As I mentioned a personal preference which others may consider unnecessary. Their preference.

This may clear things up a little;

Taken from Ashcrofts website

The MT82 6 speed gearbox fitted to the 2.2 and 2.4 TDCi is prone to the spline on the rear output shaft wearing which causes a total loss of drive, this spline 'frets' as it is dry in the same way the earlier LT77 and R380 mainshaft splines wear in the transfer case input gear, same thing, different spline.
The MT82 mainshaft comes out of the gearbox and a female/female coupling shaft (LR030054) is fitted to this with a large bolt.
A male/male coupling shaft (TUD500020) then fits into the LR030054 and the other end goes into the transfer case input gear.


The spline that wears is the one at the rear of LR030054 and the front of TUD500020.

My shaft is one piece - effectively not having this dry interface.

Comforting to know even the big boys have design mistakes and make shafts that fail sometimes

Sorry Sheldon, but the Ashcroft example doesn't do it for me. It doesn't tell me what parts in the entire train of connections are lubed or not lubed other than the TUD500020 not getting lubed. For example is the bolt held union between the MT82 output and the LR030054 lubed or not. Assuming not lubed, then seems to prove bolted connections survive un-lubed - on the other other hand if this connection is lubed then yours may need lube at the MSA/stub bolted union, as well as the input gear end which we all understand.

Sheldon, in your view for the sake of clarity, will the msa/spud shaft union (bolted) survive long term without lube. The other end should be fine if the input gear is cross drilled.

Originally Posted by steveG

Unless I've misunderstood, its going to have a large bolt up its guts to hold it all together. Grease, antiseize, loctite or your potion of choice - its effectively the same setup as the original output flange from a spline wear perspective.

Steve

I see it a bit differently; the original flange is oil lubed:



The MT-82 part LR030054 gearbox output spline is lubed in the same manner. You can see the landing for the oil seal on the part.

Working off Damien's picture showing the face where I presume the adapter mounts, there's no rear seal at all as the rear housing is removed - so the interface will be lubed with I presume a seal running on the outside of the adapter shaft to the adapter housing. The interface will therefore be lubed with gearbox oil, as the others are.

Dervish, I'm hoping in practical terms what you say does happen.

Using the MSA diagram above for memory support.

My experience. I took the drive flange off the output shaft, no oil evident.

Then off came the cover we all put into the parts bin, and all I saw in it was a couple of drops of very black oil indicating no contact with new oil ie oil changes.

Then off the output shaft comes the speedo ring. Followed by a large washer behind the speedo ring.

The big support bearing for the output shaft is now exposed - from memory it was a sealed unit, those type with plastic facings you can pick out of their mounts if you want clear access to the ball bearings.

It's just my impression, with a sealed bearing in the way, big washer and speedo ring to boot, the system is going to be hard pressed to flush Sheldon's spud shafts with oil. Maybe I'm wrong and something does get through. Also considering that the drive flange/speedo ring/washer combo are all held tight against the inner bearing race with no gaps for oil to migrate along the splines. And that the output shaft itself is solid steel mildly press fit into the bearing as far as I can tell. If the shaft and bearing are slide fit then maybe oil could get through.

Maybe other people have found copious amounts of oil in the light weight cover cavity and along the splines. I didn't. Maybe the lower bearing hole allows the excess to drain back into the main casing?

Originally Posted by workingonit

The big support bearing for the output shaft is now exposed - from memory it was a sealed unit, those type with plastic facings you can pick out of their mounts if you want clear access to the ball bearings.

I saw the bearings with grease covers in Damien's pic and thought it was odd. I'd be very tempted to remove them and let the oil through, but I don't have an Isuzu box to play around with nor do I have any experience with them so there may be something I don't know about going on.

Not a bad idea Dervish, with the plastic seal inserts removed from the bearing and some cross drilling of the spud shaft you might get enough lube. My guess is that it will be reliant on splash rather than the ebb and flow of oil at the gearbox fill level. Must have another look at the cover plate we all remove and have another look at the profiling within.

I assume Sheldon's design keeps the big washer and speedo worm which increases the distance oil must travel before getting to the spud shaft.

Just trying to remember if those holes at 9 and 2 o'clock go into the main body of the gearbox or are blind.