Help Needed, LT95 Transfer Box Gone South

[missingsid]

Hi Guy’s, someone out there might know how to help?

Before I dismantle my Transfer Box to investigate I would like to as for any experience from here?

My Centre Diff had been noisy for a while (unfortunate habit of leaving the Handbrake on doesn’t help) so I bodged it by removing the play in the bearings by removing the gasket until such time as I could replace them obviously not the best idea I’ve Had!.

Wednesday I had four bridesmaids to take out for the day and as a six seater was too expensive and my V8 Hybrid seats six, my new wife and I decided to use it instead.

Before leaving for the day I topped up the Transfer Box with the correct oil to the level and checked the tightness of the Centre Diff cover bolts.

My Hybrid has RR ratios and 7.50 tyres so it is a little over geared and with six occupants it was not too happy on some of the hills.

Symptom one, as I was going down hill I came off the gas and the TB popped out of gear, this only happened once in two to three hours.

Symptom two, on the way home I pulled up at a set of lights, on green I pulled away, twenty feet later the vehicle started to slow down and the engine slowed and laboured followed by a big bang and the TB popped out of High Range again. I popped it into Low range to pull up onto the verge and stopped. I put it back into High and drove along the verge, all seamed OK so I pulled back onto the road. Another bang and the TB again hit neutral, this time I decided to get the RAC to get me home.

When the RAC turned up (two hours later) we pushed the LR forward to give the truck more room and it rolled easily with the TB in High and the GB in neutral. It also moved onto and off the truck easily.

Back at home I had to move it to the drive way but even in Low it kept jumping out of gear.

Today I tried to perform some investigations, I figured that the centre Diff may be locked so after putting in chocks I tried the following:

Firstly - I left it in nuetral and H/B off I lifted a front wheel expecting it to unwind, it didn’t then I tried to rotate the wheel, it was free as normal.

Second – I put it in gear and lifted the motor on one side to get two wheels on one side off the ground.

Turning the rear wheel easily caused the front wheel to rotate in the reverse direction.

During these tests there were no grinding sounds or clunks.

So what do I take from this? I guess the bearings are not ceased up and that the Centre Diff is OK.

Question to the panel, has anyone had similar problems or experience, if so what do I need to replace? The answer to this may reduce the work that I need to do before I open it up?

Cheers,

Marc.

[Hybrid_From_Hell]

I had something similar in the Hybrid, drive then no drive ....and some bangs

Turned out to be the centre diff gone bang, .....

drive was when the broken bits "Erm Meshed" and then drive lost when they "Unmeshed"

Nige

[missingsid]

I had something similar in the Hybrid, drive then no drive ....and some bangs

Turned out to be the centre diff gone bang, .....

drive was when the broken bits "Erm Meshed" and then drive lost when they "Unmeshed"

Nige

Hi Nige,

This is what I expect, it's a bit difficult to hear the grinding above the V8

[Steve Hiatt]

When these boxes were comon for racing it was usual practice to hold the h/l lever in with a bungee cord.

I've raced for quite sometime a box that would jump out with a huge bang and required a taught bungy to keep it in place. Once securely in place they function as normal.

[Hybrid_From_Hell]

You may be right there Steve, know exactly what you mean.

I didn't post that tip as

A - I am knackered and clean forgot

B - The bit about it slowling down (read jamming up and causing the slowing down ?) in the post

But You may be right, far cheap fix to buy a Bungey cord than pull the centre diff

nige

[Steve Hiatt]

Nige, you're right I did think about the slowing down bit after I posted.

However, as we both seem to agree that it's best not to break out the spanners & hammers unless it's fallen off or stopped, local testing with a bungee cord would be the serving suggestion.

[missingsid]

Hi Steve,

I will try but it was quite difficult to hold in gear just getting it on the drive.

Cheers,

Marc.

[Guest noggy]

i remember on my grandads 3.9 rrc, he had the h/l box held in high with a bungee cord for years.

[missingsid]

Hi again,

Well I dropped the oil out of the Gearbox and it was as cleans as the day it went in, the Transferbox oil was another story.

It came out black with a few bits and stank like nothing on earth, worse than baby poo. I had to struggle to keep my food down!

So I guess the bearings are gonna be toast at least?

Will update when I get a chance to pull the bottom plate and Diff out.

Marc.

[bill van snorkle]

Hi again,

Well I dropped the oil out of the Gearbox and it was as cleans as the day it went in, the Transferbox oil was another story.

It came out black with a few bits and stank like nothing on earth, worse than baby poo. I had to struggle to keep my food down!

So I guess the bearings are gonna be toast at least?

Will update when I get a chance to pull the bottom plate and Diff out.

Marc.

LT95 type transfercases are very sensitive to lubrication breakdown compared to series or LT230 transfers.

The symptoms you mentioned are not really related to the centre diff. On LT95 transfers the change from high range to low range is viaa 3 piece intermediate gear assembly.There is a sliding dog clutch attached to the middle constant drive gear of the intermediate gear assembly. sliding this dog clutch to engage with the forward gear gives high range, engage with the rear gear gives low range. Excessive clearance due to wear in the 4 bronze thrust washers in the assembly will allow the gears to float backwards and forwards from drive to coast, eventually wearing tapers on the male dog clutch teeth of the high range gear in particular and on the female teeth of the sliding dog clutch itself, causing it to pop out of gear. I've had vehicles in the workshop that jump out of high range so violently that they jump straight into low range, often with disasterous results.

The seizing symptom sounds like the low range gear trying to weld itself to the intermediate shaft and roller bearing. Even in high range, the low range gears are in mesh and there is a large rotational speed difference between the constant drive gear and the low range gear intermediate gear, which can reach warp speed at times,and if any bearings begin to fail it is similar to having both ranges engaged simultaneously.

Bill.

[Steve Hiatt]

Bill is excactly right. The thrust washers are available in different widths so you can shim it up properly. It's a pain to get the shaft, gears and shims back in with the gearbox in, but possible with patience.

I used to remove the low range gear to reduce heat/wear when racing.

[missingsid]

Hi Bill, Steve,

If I have got this right then.

If the Low Range Gear has not welded to the shaft and made it impossible to remove I can re shim the Intermediate Gears.

However there is a very good chance that the dogs are worn and past use anyway?

Sooo, If the Low Gear has siezed onto the shaft the whole box is useless as I can not remove it, if not I can replace the Gears, shims and bearings etc at a cost.

Well as soon as it is dry outside I will have a look.

Thanks for the information it has realy helped me understand what to expect.

Cheers,

Marc.

[bill van snorkle]

Hi Bill, Steve,

If I have got this right then.

If the Low Range Gear has not welded to the shaft and made it impossible to remove I can re shim the Intermediate Gears.

However there is a very good chance that the dogs are worn and past use anyway?

FROM EXPERIENCE I BELIEVE THE DOG TEETH ON THE HIGH RANGE GEAR WILL BE WORN. tHE FEMALE DOG TEETH ON THE CONSTANT GEAR WOULD PROBABLY BE A BIT WORN TOO, BUT YOU CAN USUALLY GET AWAY WITH FLIPPING THIS GEAR BACK TO FRONT.

Sooo, If the Low Gear has siezed onto the shaft the whole box is useless as I can not remove it, if not I can replace the Gears, shims and bearings etc at a cost.

EVEN IF YOU ARE ABLE TO REMOVE THE COMPONENTS IT IS COMMON FOR THE INSIDE DIAMETER OF THE LOW RANGE GEAR, WHERE THE NEEDLE BEARING RUNS TO SHRINK SO THAT IT WO'NT FIT TOGETHER WITH ANEW BEARING AND SHAFT.

Well as soon as it is dry outside I will have a look.

Thanks for the information it has realy helped me understand what to expect.

Cheers,

Marc.

YOU'RE WELCOME. GOOD LUCK IN REMOVING THE SHRAPNEL. AS YOU PROBABLY ALREADY KNOW, THE LT95 GEARBOX AND TRANSFERCASE IS CAST AS A SINGLE UNIT,SO IF THE HOUSING IS CACTUS YOU HAVE A LOT OF WORK AHEAD TO REBUILD THE ASSEMBLY.

BILL

EDIT. SEE MY REPLIES IN YOUR QUOTE BOX ABOVE..

[SteveRK]

Although its not the same but the oil used in superchargers smells absolutely rotten, to the extent that it can cause 'big white telephone syndrome' . I'm wondering if the Visous clutch uses a similar type of oil and has failed - hence the stink from the oil is from the Viscous unit?

[missingsid]

Although its not the same but the oil used in superchargers smells absolutely rotten, to the extent that it can cause 'big white telephone syndrome' . I'm wondering if the Visous clutch uses a similar type of oil and has failed - hence the stink from the oil is from the Viscous unit?

Hi Steve,

That's far too new, I have a standard "open" diff in an LT95.

Cheers though.

Marc

[missingsid]

Well I finally got to open it up.

Lots of gold (Bronze) dust inside and deep joy lots of melted plastic.

Checked everythng and yup the Low ratio gear is welded to the shaft which has spun in the casing.

I have managed to move the gear on the shaft but as said above it probably won't come out.

I looked at my book of lies and it says that the Intermediate shaft can only be removed once the box is off the car.

Can anyone advise if this is true? If it can be removed how? My book does not even show it.

One thing I saw once inside the TF box.

I was worried about the amount of backlash on the centre diff when locked.

It turns out it is built in!!

The slliding Dog gear has half as many teeth as on the diff and the matching teeth on the front output shaft has half as many teeth as the slliding dog. This means that although the sliding gear is a good fit on the diff the output shaft can rotate back and forth.

Marc.

[bill van snorkle]

Well I finally got to open it up.

Lots of gold (Bronze) dust inside and deep joy lots of melted plastic.

Checked everythng and yup the Low ratio gear is welded to the shaft which has spun in the casing.

I have managed to move the gear on the shaft but as said above it probably won't come out.

I looked at my book of lies and it says that the Intermediate shaft can only be removed once the box is off the car.

Can anyone advise if this is true? If it can be removed how? My book does not even show it.

One thing I saw once inside the TF box.

I was worried about the amount of backlash on the centre diff when locked.

It turns out it is built in!!

The slliding Dog gear has half as many teeth as on the diff and the matching teeth on the front output shaft has half as many teeth as the slliding dog. This means that although the sliding gear is a good fit on the diff the output shaft can rotate back and forth.

Marc.

The intermediate shaft can normally be pulled straight out once the speedo housing/handbrake mounting has been removed.On a servicable intermediate assembly the normal practice is to jamb a suitable large screwdriver between the t/case housing and the steel teardrop shaped thrust washer at the front of the multi segment intermediate assembly, to keep everything in place whilstthe shaft is withdrawn and a dummy shaft is inserted. The dummy shaft which can be made from a shortened scrap intermediate shaft should be just long enough to be a slide fit between the thrust faces of the transfercase housing, so that the complete intermediate gear assembly can be removed intact, and a pre assembled intermediate set can be more easily fitted with the transmission in situ. A threaded hole tapped in the back of the dummy shaft will allow it to be withdrawn by screwing an extractor bolt in and pulling backwards once you have jambed th assembly in position with the afore mentioned large screw driver. In your situation to dismantle you may need to screw a long stud into the threaded hole in the back of the damaged shaft, and with a suitable piece of pipe that fits loosely over the diameter of the shaft, and a thick washer, screw a nut down the stud to extract the frozen shaft. If the stud is too small and strips you may have to weld the head of a larger bolt onto the shaft and try again.Note that the shaft has a stepped flat that abutts against the speedo housing to prevent it from spinning. If it has spun then most of the intermediate gear assembly and the gearbox/transfer housing is probably scrap anyway. Recover the centre diff and main gearbox internals for spares and get hold of another transmission to recondition.

Removing every second tooth from dog clutches is an old almost unique Rover design feature that supposedly makes changing gear, changing ranges, engaging front wheel drive or locking centre diffs easier.It is a design feature I hate, particularly on the high/low range gears of series transfer cases because wear rates leading to jumping out of high range is more than doubled.

Bill

[missingsid]

Thanks Bill,

You have again delivered the goods

I have a bolt the correct size so I just have to sort out a peice of tube.

I've another old Box so I neet to decide how badly damaged the casing is on this one to see if I need to change them.

From what you've said before I doubt that I can reuse this box but I will soon find out. I guess the reason why my book of lies says the box has to be removed first is cos they did not want to explain how to do it!

Steve's earlier comment about removing the Low Ratio gear explains why Ashtrans dad used to sell a double High Ratio conversion for Comp Safari LT95s.

Thanks Bill I knew I could rely on you for a response.

Cheers,

Marc.

[bill van snorkle]

no worries Marc.Glad to be of assistance.

I assume on the double high range conversion you mentioned, that the centre differential was deleted and replaced with a shaft that the much smaller diameter output gear would ride on?

Bill.

[missingsid]

no worries Marc.Glad to be of assistance.I assume on the double high range conversion you mentioned, that the centre differential was deleted and replaced with a shaft that the much smaller diameter output gear would ride on?Bill.

To be honest I'am not sure, Steve would probably know as he raced more than I did. It is quite possible that you are correct as racers that serious would not want a centre diff as it is a weakness.With 2 x Hi Range I presume that this would spread the load across the 2 sets of gears equally?I am sure that Dave (ashtrans) would also know.A mate and I just played with road legal racers. MarcPS.Although  have not had much dealing with Dave Ashcroft from what I have seen on here and his PM to me , he has the same degree of helpfulness as Ian.A truely great family who are happy to help even though it may not bring financial benefit.

Sorry licking over.