Thread: Maxi drive reduction gears

there is some noise associated with the mismatch contact of worn gears to new ones. Its similar to the howl you get from the diff if you pooch the setup on the CWP of one of them.

however as already alluded to most of the noise from the reduction drive sets is because they have a square cut set in there

"You ain't heard nothin" yet". If they are spur gears, then they are noisy. Wait until you have a ride in a Bugatti with straight cut centreline crownwheel and pinion in the diff and an all spur geared transmission..

I used to own an old Buffalo Pitts MT4 drill press with a reduction gear train of straight bevel gear pair and changeable spur gears. Feed box was also spur geared. It could be heard over any and all other machines in the shop. It weighed nearly 3/4 ton.

Originally Posted by isuzurover

Yes - not much difference in diameter between the 30% and 49% gears apparently. However it isn't a big area to grind.

Don't think so, pretty sure 30% go straight in, its only with the 49s that the case needs attention.

I've has both.

Regards
Max P

Originally Posted by Blknight.aus

there is some noise associated with the mismatch contact of worn gears to new ones. Its similar to the howl you get from the diff if you pooch the setup on the CWP of one of them.

however as already alluded to most of the noise from the reduction drive sets is because they have a square cut set in there

I don't know where you or others are getting this rubbish from.

When the 30% or 49% reduction low range gears are fitted into an LT230, NO new gears are meshed with worn gears. The are 2 new gears but they only run in mesh with each other.

Originally Posted by Disco_owner

Is there any Grinding of the Transfer case housing with 30% reduction gears?

Originally Posted by isuzurover

Yes - not much difference in diameter between the 30% and 49% gears apparently. However it isn't a big area to grind.

Originally Posted by Tusker

Don't think so, pretty sure 30% go straight in, its only with the 49s that the case needs attention.

I've has both.

Regards
Max P

When I fitted the 30% reduction gears (49% was not available back then), I had to grind a fair bit of aluminium from some bosses (for bolt holes) on the inside of the gear case. I can't recall reducing the thickness of the gear case wall in any area, but may have in a small area - I still have the instruction sheets, but can't be bothered to look them up.

It was also necessary to grind a fair bit of material from a section of the steel shaft for the hi/lo selector fork (IIRC i had to remove more than indicated in the instructions). If the gear wheel for the 49% reduction set was significantly larger than for the 30% set, I don't think the shaft could survive much more material being removed.

My set came with a drill, M12 tap and M12 hexagon plug so the magnetic drain plug could be relocated clear of the new gear wheel. But my existing drain plug was much larger than M12 and fortunately I didn't have to relocate it. Others may find it necessary.

My LT230 came from a TD5 Defender.

"You get used to the noise "

it's called "industrial deafness"

Originally Posted by Bush65

I don't know where you or others are getting this rubbish from.

When the 30% or 49% reduction low range gears are fitted into an LT230, NO new gears are meshed with worn gears. The are 2 new gears but they only run in mesh with each other.

because I had a brain fart and was thinking about the series box reduction units that used to be made by marks adaptors.

Originally Posted by Bush65

When I fitted the 30% reduction gears (49% was not available back then), I had to grind a fair bit of aluminium from some bosses (for bolt holes) on the inside of the gear case. I can't recall reducing the thickness of the gear case wall in any area, but may have in a small area - I still have the instruction sheets, but can't be bothered to look them up.

It was also necessary to grind a fair bit of material from a section of the steel shaft for the hi/lo selector fork (IIRC i had to remove more than indicated in the instructions). If the gear wheel for the 49% reduction set was significantly larger than for the 30% set, I don't think the shaft could survive much more material being removed.

My set came with a drill, M12 tap and M12 hexagon plug so the magnetic drain plug could be relocated clear of the new gear wheel. But my existing drain plug was much larger than M12 and fortunately I didn't have to relocate it. Others may find it necessary.

My LT230 came from a TD5 Defender.

My gears (in fact whole T-case) just arrived today - Thanks MR/Warren and Jamie!!!

To answer the tooth count issue, they are as follows:
26/41/23/72
Input/Intermediate/Low-Int/Low

Which by my calculation gives 4.94:1 low - exactly 49% lower than 3.32:1

The 30% gears are apparently
26/41/20/55

The low gear for the 49% set is only 3mm larger in overall diameter than the 30% set. 184 mm as opposed to 181 mm.

The 49% instructions are added at the back as an addendum to the 30% instructions. A fair bit more case grinding is needed compared to the 30% set. If you look at the RHS of the case from the outside, there is a small indent about halfway up. The thickness of that section is reduced to ~3 mm.