Thread: Borg Warner TC questions

The VC controls the relative rotation of the front and rear output shafts but there is still a centre diff like normal. It is possible to drive a VC without the front shaft but takeoffs should be done very gently so as to not induce too much torque on the VC. Give it heaps and it'll get hot and explode. The old 1990 RRC I bought for wrecking was running around without a front shaft due to a uni failure, it still drove adequately in anything other than low range and full noise in first gear.

The hi-lo range is rod operated by a simple lever on top of the trans, at least on the 1990, going back to a pivot above the transfer case.

Thanks for that - it should allow me to do some tests with the front shaft out then - that's all I need, not extended driving.

Cheers.

Originally Posted by bacicat

So, questions are - with the viscous coupling -


(a) this is designed as a replacement for a centre diff lock right?

(b) What is the effect of removing the front drive shaft and driving the vehicle?

(c) Will it send all the drive to the back?

I don't know how they work as far as directing power to the front or back. I just want to see how it drives without the prop shaft rumble.

.

(a) Yes, sort-of, to automatically engage diff-lock, so that Sir does not need to trouble himself with the belittling task of moving a lever...

(b) You will be in command of a RWD Range Rover, and be able to progress properly on gravel... hands turn the front wheels and your right foot guides the rear wheels. This will be a new experience for any RR/Disco pilot who don't use 'ordinary' cars..

(c) Yes it will, eventually. - That being a matter of a few revolutions of the now-disconnected front output. This is why you don't hoon it off at the lights, rather, one 'gets under way' in a dignified manner. So you can drive it gently and not too far, without either prop shaft. No one has succeeded with both removed...

Think of it as device that is mechanically attached to both output shafts of the centre-diff, and reluctantly allows a small speed differance. - the diff will happily so what open diffs do.. but the Viscous couipling is constantly trying to keep this from happening, the more it the variation, the harder the VC locks together the shafts together. Simple.

Am told the BW system is excellent on sand, but not so robust or predictable on hard, grippy Ruff Stuff.

Mine has failed.... locked. Eventually I'll get around to replacing it.

Hope I'm not hijacking someone elses thread, but I can hear a bit of wheel squeal/shudder etc when parking/doing u-turns. Figured its this VC thing from what I've been reading.


Are they easy to remove and replace, or is there a way I can take mine off and "unstick" it?


I need to drive mine to work and around town till I get a replacement one, so as said in the above posts, if i disconnect the front drive shaft and drive carefully, will it be ok for a week or so?


Have heard there the same as a p38, that true as well?
thanks, and again, sorry if this is classed as hijacking!

A new one is required. As you mentioned, pull the front drive shaft out and you'll be fine. You won't need to baby it too much like that, you'll just notice a bit more lash in the drive system with the front shaft gone.

Hijack to your heart's content. All good info and experience.

Amen to that. Mine has been RWD for a Quite A Long Time. No, not telling how long, - too embarrasing. Now that #1 Son has 'borrowed' the car, it might get done this year...

Seriously, take the "gentle" advice given here by others, stay ON road and all will be well.
Spencer-King, so I'm told, had two great ideas for unstoppable off-roaders. Massive and soft articulation which kept an even amount of weight on all 4 wheels...and equal drive all round. - This meant AWD with a centre-diff, not just a conventional and cheaper transfer case. Rover diffs/axles were regarded as underbuilt for the new, 'powerful' V8.... so splitting the drive halved the load on each. A no-brainer and less expensive for them in the long run.

Roundabouts are a great diagnostic tool for the VC... The smaller it is, the more chirping and squealing. In the wet you'll notice your turning circle is suddenly more like a cruise ship...

You can replace the VC by itself. No,can never be 'fixed'. Sealed unit and rebuilding is impossible/dangerous/too expensive. Ashcroft sell them on-line. Invariably, the output shaft will need replacing too, or at least inspection.
VC can be replaced 'in situ' but you'll need acces to a bearing press and expertise. - Take off the front housing, replace, put it back in and attach prop shaft.
Don't forget to refill with top quality fluid.

P38s run the same stupid idea, but for some reason they also kill the chain faster whilst sparing the output shaft splines. - Classics are the opposite, AFAIK.

Get the RAVE CD from the shop here, print out the section and read it at bedtime!