Oil for worn transfer box

[hermit]

Hi All

Hope someone can help with my problem. Its in the transfer box of a high mileage Land Rover. There is a known fault with these. Land Rover assembled the input gear and spline dry and there was no way for the splash lubricating gear oil to get between the two. Subsequently they wear badly and fail. Mine has a new modified cross-drilled gear fitted which allows the gear oil to enter, but the spline is 50% worn through. It doesn't warrant hundreds spending on a recon box so I was wondering if anyone can recommend a lubricant to protect the worn spline and postpone the inevitable as long as possible? I use the Land Rover for towing livestock trailers and the temperature here rarely drops below -10c.

Currently Land Rover spec 75w90 GL5/MT1. My question is, can I reduce the chances of failure by using a different spec, but still maintaining adequate splash lubrication of the input gear and bearings? Possibilities I had though of were:

1) Synthetic 75/80w140
2) Redline Heavy Shockproof (concerned about splash lubrication with this)
3) Redline Light Shockproof
4) Using MoS2 in a synthetic gear oil

Any advice on how to reduce the chances of failure in this box would be greatly appreciated.

Thanks

Neil

 

[pajim17057]

I would just stick with plain ol dino 80w90.

 

[hermit]

Thanks for the reply, but the recommended spec is a semi 75w90, I don't think a mineral will prolong the life span of a problem box. Can anyone else suggest any options?

Neil

 

[Whitewolf]

I don't think so hermit. It's going to go isn't it? I don't think that we can delay that event much with lubricant. I would think that the last thing you need is a failed t-case and a trailer full of livestock in the middle of nowhere!
Anyone got a lube that can replace metal?
I don't think we can help you mate, sorry.

 

[KBFXDLI]

Id try the redline 80-140check their website on the gear oil page as one of the heavy weight gear oils will quiet noisy boxes.

 

[unDummy]

The goal is to prevent the failure as long as possible.
Use any of the GL5, GL5+ or GL6, 140wt full synthetic gear oils.

 

[TheLoneRanger]

I agree with using a 75W-140 full synthetic. If the spline is already 50% worn through, I'm not sure if any lube is going to save it. Be very careful with shock loads on it, and have curse words ready for Range Rover when it does fail.....

 

[bmwtechguy]

Check with the Schaeffer rep. IIRC they have some gear oils designed specifically to quiet and smooth noisy gears and brgs.

 

[hermit]

Thanks everyone for the useful advice. I know I should replace the transfer box, but if I go down that route the main gearbox and clutch might as well be done as well which is scarey money!

We can only get Redline 80w140 here, not 75w140. Alternatives would be Amsoil severe gear 75w140 (although thats $30 a quart!) or Castrol SAF-XJ 75w140. Would these give sufficient splash lubrication at low temps?

Alternatively I could mix Redline 75w90 and 80w140. 50:50 would give an 80w90 apparently.

Neil

 

[1040 WreckerMan]

Thicker is always better for gear assemblies (for wear anyways). The best thing to do would be rebuild the box, but you want to get as much life out of it before that and you seem to accept the fact that the lube change will just be a band aide.

The difference between a 75 and 80w oil is not much as far as cold flow is concerned in most cases. Since you need the extra viscosity to help cushion and support the extra load imposed by the warn spline, I would run the RedLine 80w140 or the Castrol 75w140 since these are readily available and priced better than the Amsoil.

 

[hermit]

Thanks WreckerMan, sound advice. Price aside how would the SVO stack up against the other two?

Viscosities I have seen are for those two oils are:

SAF-XJ 75w140
40c 177
100c 25
Pour -54c
Brookfield 140k @ -40c

Redline 80w140
40c 269
100c 27
Pour -40c
Brookfield 59k @ -26c

Is the Redline going to give me splash lubrication problems at low temps? Lack of oil was the original cause of spline wear!

The SAF-XJ is a limited slip oil, will this cause any problems? Does anyone know the make up of this oil and how tough it is. I emailed Castrol about yellow metal compatibility and they said:

"I would be suspicious of using some GL5 products that have sulphur EP additive packages when the oil gets hot - the SAF-XJ uses different chemistry so we wouldn't have any problems with that one"

So what does it use instead of sulphur EP additives?

Neil

 

[mdv]

Why worry about yellow metal compatibility if Land Rover already specs GL5 lubes?

 

[LargeCarManX2]

Do a google on "Power Punch" it is an additive an old tech say's really works!

 

[1040 WreckerMan]

Power Punch is I think, just some bright stock with EP adds, but I could be wrong. Power Punch has been around for eons and I'm not sure they have really updated their formula all that much. It would work great to just thicken the oil some though.

hermit - what kinds of temperatures do this vehicle see? I would say, with out plugging in numbers to vis calc, that you would be fine with either to around 0*F or a bit lower. Lower temps than that and the Castrol would have a slight advantage. I find that even in very cold weather, transfer case and axle oil temps will rise enough in a short period of time to provide some lubrication. I try and drive reasonably until the oil does warm to about 50% of operating temp.

They could be using some type of borate EP additive like the Delo ESI lubes. There are some types of EP additives in use now that are pretty gentle on yellow metals. I would not worry about this much since the box is already spec'd for GL5 and there typically aren't yellow metals in a transfer case. Also, if there doesn't appear to be anything wrong with the main box I wouldn't tear into just because the transfer case needed a rebuild.

 

[hermit]

Thanks again WreckerMan

We don't often get below 14F here, 0F is very rare. So is the 40c viscosity figure a poor indicator of good flow at low temps? There seems a marked difference between the two figures. I'm tempted by the Redline as it has such a great reputation, is ester based, is marketed as GL5+ and their data shows the 80w140 as having a significantly better cold flow at 0c compared to a petroleum 80w90.

I think the yellow metals are just brass shims, Land Rover used to spec SAE90 GL4.

I appreciate your time and help

Cheers

Neil

 

[1040 WreckerMan]

Those temperatures were of course just a round figure, please don't take them as gospel. There is a significant difference in the 40*C viscosities, however both are acceptable figures I think. Another point that should be considered is the usage of the vehicle. If it does mostly short trips where the gear oil is likely to not warm much, then a thinner oil would be better.

I prefer to look at the entire problem and try and pick an oil that address as many aspects of that problem as possible. In order to provide the longest life for the damaged hard parts you need a thick oil and have to give up a bit of low temp flow. Since your case used gear lube, it is probably not pressure oiled, which means the oil only need by fluid enough for to climb the gears to initially lube the main shaft (I'm assuming the mainshaft is the highest in the box). If you are inclined to run the Redline I would do so without worry. Nice thing about oil is, if it doesn't seem to be working well you can just drain it and try something else

 

[hermit]

Thanks WreckerMan

Yes the input gear and shaft are at the top of the case and are splash lubricated. Apart from the odd longhaul it will be a local runaround so perhaps the SAF-XJ would be better.

At least I know I'm on the right path with an xxW140.

Neil