Lt 77 noisy gearbox or transfer case

[GregK]

Hi. 

Can I pick your brains please?

I just bought a Lr90 2.5 petrol with noisy gearbox or transfer case or both and can not decide where the noise is coming from [think its the gearbox main shaft.]

The noise is metallic similar to drum or disc rubbing on back plate. It comes on at around 20mph and noise increases  with speed.

In 2,3,4,5 gear coasting or dipping the clutch makes no difference still there but if I put transfer box in neutral while rolling and then press the clutch the noise goes away. Stationary with transfer box in neutral   and going up in gears noise is present. Thanks in advance for any input.

[miketomcat]

Sounds like a gearbox or transfer box input bearings. If it goes quiet with gearbox and transfer box in neutral while rolling then it's likely transfer box input bearings. Often people change the input gear due to wear but don't change the transfer box side of the bearings thus they wear quicker.

Mike

[GregK]

Thanks Mike for your input. I was hoping it be one or the other . So looks like I have 3 options. Bearing in mind the Landy is 1988 2.5 petrol. 

1. Ideally I should rebuild original gearbox and transfer box providing I can find someone reliable  to do it locally [I hate gearboxes or should I say smell of gear oil so rather don't want to do it myself if I can help it] 

2. Get remanufactured gearbox and transfer box, probably  most expensive option.

3. Second hand. [cheapest]

Now I have found locally second hand lt77 short box with 300tdi disco transfer box 122 ratio bolted together , seller says both are good units the only thing I'm worried about is that the gears be too tall for the engine. Has anyone got an idea if that will be the case?

Which option would be best to go for?? 

 

 

[miketomcat]

Personally I don't like the 1.22 box in anything unless you're running 29" tyres. Defender LT77's are getting hard to come by so I'd be tempted to buy the one locally regardless. Lt230 are generally bullet proof so I'd comfirm if it's the input bearings or not, if it is then change the bearings and go from there. It will come down to budget and how long you plan to keep the truck.

Mike

[GregK]

Ok thanks for that. One more he wants around 500 for both so I presume buy it, separate the transfer box and sell it on just to make some money back? Or just refurb my old one. I don't mind spending money on it to get it right.

[FridgeFreezer]

12 hours ago, GregK said:

The noise is metallic similar to drum or disc rubbing on back plate.

It's not a dragging handbrake or something simple like that is it?

[GregK]

10 hours ago, FridgeFreezer said:

It's not a dragging handbrake or something simple like that is it?

I wish it was that simple ☹️. Hand brake drum was first thing I checked.  I also put transfer box in neutral  and went up and down the box it was still noisy. 

[Snagger]

I have had similar noises from a prop shaft flange mud shield clipping a diff nose or transfer box output bearing nose.  It only needs to scuff lightly to make a racket.  I have also had prop shaft UJs make noises like stirring a cup of tea with a teaspoon.

[GregK]

1 hour ago, Snagger said:

I have had similar noises from a prop shaft flange mud shield clipping a diff nose or transfer box output bearing nose.  It only needs to scuff lightly to make a racket.  I have also had prop shaft UJs make noises like stirring a cup of tea with a teaspoon.

This one doing it while stationary with transfer box in neutral so hand brake and propshafts are not spinning this eliminates props,handbrake and diffs.

What I did notice and tested is that while at say 40mph when I select neutral in gearbox and transfer box all goes quiet. This eliminates hand brake and props or axles noise.

I think it might be a transfer box what I will do when I get a chance is pull input gear out the transfer case and run it thru gears to see if noise is still there if noise goes away it can only be transfer box.

I did buy a second hand lt77 with 300tdi transfer case 1.2 ratio supposedly in good condition so see how it goes when I put that in. 

Edited July 22, 2023 by GregK

[Snagger]

It’s probably the input side of the LT230.  The replacement might fix it, but may have its own issues - you never know what you are getting with secondhand.  The Ashcroft rebuild kits have all the usual parts needed for refreshing a box, the only difficulty likely are if the intermediate pin wore its locating hole or if the initial issue responsible for the noise has caused other damage to shafts or gears.

There is nothing to stop you fitting the used boxes and then rebuilding your original units at your leisure, and then refitting them later, keeping the replacements as spares or selling them on as appropriate.  But rebuilding them is the only way to know what you have, and very few don’t need some TLC at this age.

[GregK]

Yes rebuilding  old boxes at my leisure is a plan for the future.  

[GregK]

Just a little update. The noise ended up being a transfer-box input gear bearings. They were worn. Replaced with new bearings and cross drilled input gear in situ and it is a lot quieter. There is faint main shaft bearing noise in a gearbox but its ok for time being. When I get round to stripping second hand box I will replace all bearings and then put it in a landy.  Thanks everyone for help  and pointing me in a right direction 

[markyboy]

19 hours ago, GregK said:

Just a little update. The noise ended up being a transfer-box input gear bearings. They were worn. Replaced with new bearings and cross drilled input gear in situ and it is a lot quieter. There is faint main shaft bearing noise in a gearbox but its ok for time being. When I get round to stripping second hand box I will replace all bearings and then put it in a landy.  Thanks everyone for help  and pointing me in a right direction 

Wow, that bearing was in a bad way!

[GregK]

3 hours ago, markyboy said:

Wow, that bearing was in a bad way!

They sure seen better days.  Oddly there was no spline wear on the input gear or mainshaft.

[Sigi_H]

It seems to be rusty. Thats why I change gearbox and axle oils, when I was in Iceland.

 

[GregK]

24 minutes ago, Sigi_H said:

It seems to be rusty. Thats why I change gearbox and axle oils, when I was in Iceland.

 

I only just bought it with a noisy Bearings . Oil came out nice and clean when I drained it so someone has changed it. Landy stud for a while unused so that might  also be why it rusted. Or lack of oil at some point, more likely.