Now that I have had extensive experience, long term using of LT230 transfer gearbox in my 2004 Discovery, and using of Borg Warner viscous coupling transfer gearbox in my 1991 classic Range Rover, I thought that I would share here on this site, my impressions of both gearboxes, especially in view of fact that many guys switch out their Born Warner for the LT230:

The LT230 is a Land Rover designed and made gearbox, while the Borg Warner is designed and made by Borg Warner, of course.

The LT230 transfer gearbox is gear drive, transferring power from the transmission to the front and rear differentials via. GEARS. Further, it has capability for center locking, for temporary use locking front/rear transfer. The downside of this center diff. lock is that if not used properly, one can wind up this center differential, transfer gearbox, and literally destroy itself and/or other drive train components, such as front differential, front hubs, etc. I have done this, so I know it is quite easy to do, if you don't use locking LT230 properly.

The Borg Warner transfer gearbox is CHAIN drive, transferring power from the transmission to the front and rear differentials via. a huge wide CHAIN.

Some guys say the LT230 is a stronger gearbox, while others say the Borg Warner is a stronger gearbox; some say they are equally strong.
I have not known anyone breaking any gears in their LT230, but I have known numerous guys say that they have had the Borg Warner chain STRETCH (I am included in that group, finding several chains that obviously had stretched from use, including one in my 91 RR), and I have known several guys who said that they broke their chains, from use. The stretched chain gives a spongy sloppy "feel' to low range 4 wheel drive.

The Borg Warner transfer gearbox has a viscous coupling, rather than a Center differential lock, that automatically couples the front/rear drive together, whenever one wheel begins to slip, front or rear, similar to LT230 that locks them up as long as it is engaged. A strong drawback to the viscous coupling is that it will permanently freeze up after about 100,000 miles of use, normal life expectancy, and is capable of freezing up any time due to part failure, and/or due to owner abuse, such as having different size tires, front to back. Should viscous coupling freeze up and vehicle be driven on pavement, with no opportunity for surface tire slipping, it is likely that one can destroy transfer gearbox and/or front differentials, front hubs, other drive train components, etc. I should know, for I have done exactly that. Everything considered, after long term use, personally I prefer by far, the LT230 gear drive transfer gearbox over the Vicious Viscous coupling Born Warner stretchable chain drive transfer gearbox.

 

All I know is, the LT230 is one of the better things that came from Leyland.

 

Thanks for the write up earlyrover. One question, for someone that literally just found out yesterday that they have a Diff Lock on their transfer case... How would you best describe "using it properly" as to not result in the destruction of the tcase itself? Any tips on what not to do??

 

I've always thought that the Borg Warner transfer case would be an interesting addition it a 2002-2003 disco instead of adding a CDL LT230, assuming it would fit of course. Then you wouldn't need to worry about finding a transfer case shifter with the locking feature, and no user input would be required. I doubt it would be as capable as a fully locked lt230, but I bet with traction control of the D2 it would be pretty decent. The p38 uses a different bw case that isn't compatible with Rrc or d2, but the idea is the same and it functions with traction control ok.

 

With working traction control on a d2, your risk of blowing it up is low. On d1 or a d2 without working tc, driving off road without the lock engaged in a place where wheels can slip can blow up the center diff. Basically lock it off road or risk breaking it.

 

You are spot on with the Viscous Coupling. My old 1994 ZJ Grand Cherokee had a New Process unit. I actually made 180k miles before the viscous coupler "gave up the ghost".

The way it failed, it wouldn't allow me to enter low range. It worked fine in high, but I swore I would never get an AWD viscous coupling transfer case again.

So what'd I do? I bought a Disco without a CDL! Lucky for me, it was geared and the CDL was available, I just have to tie into it.

If you want to keep your vehicle for a long time, and reliable, it is very tough to beat a geared transfer case.

One thing you forgot to mention is the 230 has helical gears, so they are very quiet in low-range. A more expensive and nice design, to be sure, but I find myself missing the familiar "lo-range whine" of the 4x4s of yesterday..

 

Correct me if I'm wrong, but you would only risk "winding up" your driveline and ruining a T-case if you are on a type of surface (such as dry pavement) where the wheels CANT slip and the CDL is on).

Slipping with CDL off (TC working or not) is just fine, on or off-road, that's why AWD cars and SUVs don't have a locking center diff, it's to protect from wind up.

I believe the 230 Rover case has been used in Rovers before the development of the Discovery/H1 Traction Control.

 

You are more likely to damage it unlocked. Lack of lubrication of the small spider gears in the case will cause them to weld to the cross pins and then they blow up.

It's not good to drive locked on hard surfaces either. Basically lock it when you need it and unlock it when you don't.

 

Here's what Ian Ashcroft says about running open center off-road.Cross shaft for LT230

Mine wasn't broken from running like that however, it was from another cause.

 

That makes sense then. So the idea is to use it like a full-time 4wd t-case as it was originally designed (when off road). I can handle that.

This makes it even more questionable that Land Rover removed it in the first place and allowed an electronic gizmo to lubricate your case..