Borg Warner Transfer Box into 300Tdi 110

[DaveSIIA]

The LT230 in my 300Tdi 110 was getting a bit worn and noisy, having had 280k miles of fairly hard driving. The Borg Warner transfer box came out of a 92/3 3.9 RRC and had been recently refurbished. Best of all, it was a freebie.

Fitting was straight forward - LT230 out; remove drivers side gearbox mount rubber; drill extra hole in BW drivers side mount plate for locating pin of 300Tdi mount; install BW transfer box to back of R380 and drop onto existing mount points.

Rear propshaft is the standard 300Tdi 110 item. The RRC front propshaft was fitted in place of the Defender item as the forward output housing of the BW is ~2" shorter than the LT230 - propshaft ~2" longer.

The 300Tdi handbrake back plate required an extra hole drilling (10mm dia) to pick up all 4 holes in the BW rear face (top left when looking forward, centre 25mm clockwise on same radius from current hole).

The speedo drive gear was removed from the LT230 and slid straight into the rear housing of the BW - no speed recalibration. Speedo cable was a direct fit.

High/low shift used the rod from the RRC to the Defender lever assembly. Diff lock position was locked out (BW has a viscous coupling) by sliding a length of 1/2" hose over the shaft and refitting the nut & bolt.

The 300Tdi even has the wiring in place for the transfer box oil temperature warning light switch (slate/red and a black) and only required a bulb fitting in the right position in the dash. Wires for the diff lock switch were folded back and taped to the gearbox loom.

First impressions were very favourable - a lot quieter than the LT230; The gear overall ratios felt right and fourth remained useable round town; feedback during cornering was much improved, with better traction/balance (the vehicle is frequently driven fairly hard); no more skipping from the front wheels when pulling hard up hill on uneven tarmac.

The proof of the pudding was a 400 mile round trip, across N. Wales for a spot of camping with the family (four up and the back of the 110 loaded to the roof with kit). We travelled over a mix of roads from fast dual carriageways to tight & twisting single track mountain B roads. Fourth and fifth remained very useable and the improved traction was noticable on some uphill hairpins.

Off tarmac, I'm happy with the way the viscous coupling behaves. There are those who would prefer to retain control of a diff lock, but this provides a viable alternative to a Disco or RRC transfer box for raising the gearing of a Defender.

[BogMonster]

Interesting conversion, I have wondered in the past about whether this was easy to do

[nicks90]

i have often wondered in the back of my mind if this was a viable replacement -

cos i do RTVs, its sometimes handy to flick it in and out of difflock if the ground conditions allow. The ability to disengage the centre diff to turn tighter is a bit hit and miss with a lt230. Bit of a reach and it doesnt always unlock.

Whereas the viscous unit would essentially be unlocked all the time, giving maximum turning circle when traction is good and auto lock up when a wheel starts spinning.

How quickly does the viscous unit actually lock up?

[BogMonster]

The viscous coupling on a Freelander locks up quick enough to make a hell of a mess of a gravel driveway when turning on full lock, so I would imagine a RR would be much the same.

[DaveSIIA]

The viscous unit seems to lock up pretty quickly. Tried it out on sand, shingle and wet grass/mud, and there doesn't seem to be much evidence of wheelspin before the VC transfers the drive to the other axle. Not exactly a scientific test as I just looked at the tread imprint on the ground to work out if a wheel had spun.

[Monster]

The LT230 in my 300Tdi 110 was getting a bit worn and noisy, having had 280k miles of fairly hard driving. The Borg Warner transfer box came out of a 92/3 3.9 RRC and had been recently refurbished. Best of all, it was a freebie.

Fitting was straight forward - LT230 out; remove drivers side gearbox mount rubber; drill extra hole in BW drivers side mount plate for locating pin of 300Tdi mount; install BW transfer box to back of R380 and drop onto existing mount points.

Rear propshaft is the standard 300Tdi 110 item. The RRC front propshaft was fitted in place of the Defender item as the forward output housing of the BW is ~2" shorter than the LT230 - propshaft ~2" longer.

The 300Tdi handbrake back plate required an extra hole drilling (10mm dia) to pick up all 4 holes in the BW rear face (top left when looking forward, centre 25mm clockwise on same radius from current hole).

The speedo drive gear was removed from the LT230 and slid straight into the rear housing of the BW - no speed recalibration. Speedo cable was a direct fit.

High/low shift used the rod from the RRC to the Defender lever assembly. Diff lock position was locked out (BW has a viscous coupling) by sliding a length of 1/2" hose over the shaft and refitting the nut & bolt.

The 300Tdi even has the wiring in place for the transfer box oil temperature warning light switch (slate/red and a black) and only required a bulb fitting in the right position in the dash. Wires for the diff lock switch were folded back and taped to the gearbox loom.

First impressions were very favourable - a lot quieter than the LT230; The gear overall ratios felt right and fourth remained useable round town; feedback during cornering was much improved, with better traction/balance (the vehicle is frequently driven fairly hard); no more skipping from the front wheels when pulling hard up hill on uneven tarmac.

The proof of the pudding was a 400 mile round trip, across N. Wales for a spot of camping with the family (four up and the back of the 110 loaded to the roof with kit). We travelled over a mix of roads from fast dual carriageways to tight & twisting single track mountain B roads. Fourth and fifth remained very useable and the improved traction was noticable on some uphill hairpins.

Off tarmac, I'm happy with the way the viscous coupling behaves. There are those who would prefer to retain control of a diff lock, but this provides a viable alternative to a Disco or RRC transfer box for raising the gearing of a Defender.

Hi Dave,

I have read your post with intrigue.

Just wondering what length your new front propshaft is. I am installing a lt230 in my lw hybrid and need new props. I had thought a front 4cyl defender would work but it is a bit short. So your one that is 2" longer seems a possibility. Do you have a part no; or any idea how i can get one? Is it a solid thin bar or the standard large hollow?

Any chance of measuring your prop? The distances between diffs and box are 720 and 520.

Look forward to hearing from you.

Cheers.

[DaveSIIA]

The propshaft is from a BW equipped non-cat RRC (3.5 V8 or Diesel). It's a standard hollow tube. I think the part number would be FTC122.

I'll be under the vehicle tomorrow, so will measure the length (flange to flange) and get back to you.

[paul stage1v8]

I had thought about the BW transfer when I do the auto conversion on my 110, but the Disco I bought for a donor had a 1.210 LT230Q transfer, which is every bit as quiet as the BW and near enough to the same ratio, 1.210 vs 1.206, but still has the positive locking diff rather than viscous. I would have always been worried about the viscous if I had fitted the BW.

[DaveSIIA]

Any chance of measuring your prop? The distances between diffs and box are 720 and 520.

Finally measured the front prop - 690mm flange to flange fitted. There is about a further 20mm compression available, not sure how much more extension (poss +20mm?).