Range Rover 1990 Transfer Case Viscous Coupling Seized

I have a 1990 3.9 EFI with ZF4HP and a borg warner transfer box under my series 2 landy. I am pretty sure the transfer box viscous coupling is seized. I am going to test tomorrow.
I have noise when off throttle slowing. Ie wheels are make the drive train turn and not the engine. It seems to be comming from the transfer box area (no sound proofing). Just after the most robust option, whats the best option to repair. Change to lt230 or will more modern p38 box fit. Help much appreciated.

cljcars said:

I have a 1990 3.9 EFI with ZF4HP and a borg warner transfer box under my series 2 landy. I am pretty sure the transfer box viscous coupling is seized. I am going to test tomorrow.
I have noise when off throttle slowing. Ie wheels are make the drive train turn and not the engine. It seems to be comming from the transfer box area (no sound proofing). Just after the most robust option. Help much appreciated.

Click to expand...

Jack one front wheel, box in neutral, hand brake on and try to turn the wheel. With a lot of effort it should be possible to slowly turn it.
Your noise does not sound like a VCU problem to me. If the VCU is seized, it's usually most noticable doing a tight turn at low speed.

Could be you hand brake shoes are shot or a bearing?
Any oil dripping (daft question alert)

Datatek said:

Jack one front wheel, box in neutral, hand brake on and try to turn the wheel. With a lot of effort it should be possible to slowly turn it.
Your noise does not sound like a VCU problem to me. If the VCU is seized, it's usually most noticable doing a tight turn at low speed.

Click to expand...

Cheers Datatek, that's what I am going to do tomorrow. Got some more checks to do. Lots of strange noises compared to my rangies. I have just bought it, got it running. Previous post on V8. Just ironing out issues at the moment. Cheers.

Mark Piercy said:

Could be you hand brake shoes are shot or a bearing?
Any oil dripping (daft question alert)

Click to expand...

Haha. There was lots of oil dripping. The zf4hp took about 4 litres to get it to the right level. The bodged atf cooler hoses where leaking......... need new, but its stopped leaking after bodging the bodge....... It shift well with no noise going up the box.
I like the idea of the drum shoes. That could be a nice cheap fix. bearing too.

cljcars said:

Haha. There was lots of oil dripping. The zf4hp took about 4 litres to get it to the right level. The bodged atf cooler hoses where leaking......... need new, but its stopped leaking after bodging the bodge....... It shift well with no noise going up the box.
I like the idea of the drum shoes. That could be a nice cheap fix. bearing too.

Click to expand...

Check the prop shaft ends and the sliding joints for side to side movement.

And the diff noses for up and down movement...
In fact just go over it all and grease your props while your there

cljcars said:

Change to lt230 or will more modern p38 box fit. Help much appreciated.

Click to expand...

Think you may find the prop side changed from the early classic BW transfer box to the later P38 BW box.
But the early is the same side as the LT transfer box.

Please check my info.

J

Mark Piercy said:

And the diff noses for up and down movement...
In fact just go over it all and grease your props while your there

Click to expand...

I tried to do this underneath today but no play in anything. It's all stiff, no movement in anything. Which was strange, was thinking it might be wound up........ but will check it all out tomorrow. Going to do all the fluids in everything tomorrow afternoon. The borg warner takes ATF doesn't it, Haynes says hypoid, but all other sources say dexron 2 or 3 like the p38, same transfer box......

Dexron 3 in the p38 box

If your viscous coupling has seized you'll be chirping tyres when turning on full lock. It don't think it's seized based on your description.
Only Dextron 2 for auto box and transfer box in my experience. Dex 3 is too thin and not suitable for 4HP22/BW viscous transfer box.
Many unexperienced garages use EP90 in viscous transfer cases by mistake and this will lead to overheating the VC and seizing it.
(RRC viscous unit is same a the P38 by the way).

Also, if you have the original Series 2 front axle it will have universal joints in the swivels, not CV joints like a Defender or RRC. Now being full time 4WD, the UJ's can create a kind of "shimmy" when going around tighter turns due to their design. It will work, but it will never be totally smooth.
With the BW transfer box in a Series, your rear propshaft will be shorter than standard (as transfer box is longer overall). Make sure it's well greased as the joints have a lot more work to do due to the increased angles.

Rangieman123 said:

If your viscous coupling has seized you'll be chirping tyres when turning on full lock. It don't think it's seized based on your description.
Only Dextron 2 for auto box and transfer box in my experience. Dex 3 is too thin and not suitable for 4HP22/BW viscous transfer box.
Many unexperienced garages use EP90 in viscous transfer cases by mistake and this will lead to overheating the VC and seizing it.
(RRC viscous unit is same a the P38 by the way).

Click to expand...

DEX III is the recommended ATF for the BW box on the P38. Oil in the transfer box has no effect on the VCU which is a sealed unit.

Two last things to check:
The BW transfer boxes are know to be very quiet in operation. If the internal chain has stretched it will make noise, and can eventually lead to total loss of drive.
Check that the yokes on your front prop are in alignment. Depending on who did the conversion you might have a modified Series prop or RRC. The yokes on RRC/Defender are not "aligned" due to the front diff being cranked at an angle. Series Landies have the diff flange and transfer box flange in parallel.

Hello Datatec,

Correct the VC is sealed, but in the many RRC and P38's that I've seen, the BW transfer boxes have lasted for more miles in the Classics, which have Dex 2 listed. Again, just my opinion from experience.

Rangieman123 said:

Hello Datatec,

Correct the VC is sealed, but in the many RRC and P38's that I've seen, the BW transfer boxes have lasted for more miles in the Classics, which have Dex 2 listed. Again, just my opinion from experience.

Click to expand...

The viscosity of DEXIII is slightly higher than DEXII but Dexron-III (F) has the same low-temperature fluidity as Dexron-II (E), for better transmission performance in cold weather.
DEX III addressed some shortcoming present in DEX ii.

Thanks lads. Another issue came up so been sorting that. Got a blocked injector, So waiting for a set to replace them.
The borg warner seems to be working, not seized, no skipping. I have custom props. So hoping they have been made the right length. They seem to be.
It has the 90s rangie axles, swivels up front which look fresh.
It drives well upto 55mph then vibration, not sure where from.
The noise defo is comming from the transfer box area, if I get chance I will drop the oil atf on the weekend and see if there is anything in it. Apart from this noise on initial off throttle it seems good. Does seem to me to be a bearing in the transfer box.

Are the tyres balanced properly?

You say custom props.
Have they been installed "phased" correctly & balanced?

J

cljcars said:

I have a 1990 3.9 EFI with ZF4HP and a borg warner transfer box under my series 2 landy. I am pretty sure the transfer box viscous coupling is seized. I am going to test tomorrow.
I have noise when off throttle slowing. Ie wheels are make the drive train turn and not the engine. It seems to be comming from the transfer box area (no sound proofing). Just after the most robust option, whats the best option to repair. Change to lt230 or will more modern p38 box fit. Help much appreciated.

Click to expand...

Worn prop sliders can make hell of a racket on the over run.