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Gearbox noise level 4spd vs 5spd


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If theres any one else i've missed feel free to comment

It would be greatly appreciated if you could briefly answer this quest.

In comparison, to when you had 4 speed boxes fitted. What was the level of noise difference when running a lt77 speed?

From experience of a lt77 recently fitted to my LWT... There doesnt seem to be much difference at lower end speeds up to 35mph. Although admittedly i have any early suffix main box from NA diesel, with no sound proofing as yet on the transmission tunnel. But it is coupled to 1.2 lt230 disco transfer. Oh and 4.7 diffs.. at the moment.

Or should i not worry, as i wont be able to hear it over the TDi? :lol:

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Its definately quieter, but as I'm still runnning the series transfer box, which wines like a b1tch, its kind of hard to tell!

At low speed its not really any different, but when you can change up to 5th its better simply casue the engine is doing lower rpm. I dont beleive the gearbox itself really makes much difference at all.


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the lt77 is definitely quiter than a series box, series boxes do vary alot though, if u're running a lt230 with series diffs then u'll be revving the engine alot higher than the standard series set up, u either need to run very large tyres, or fit a series t/box, or regear your diffs.

what size tyres u running at present?

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At the moment i have 265/75r15

A quick calc leads me to an equivilant of running a 1.6 ratio transfer box, with my current transfer and diff setup :blink:

I have 3.54 diffs to go in at a later date. I haven't fitted them yet as i thought them and a 1.2 transfer would be asking to much from the 2.25.

Unfortunately i dont have access to sufficient space to try the truck at any higher speeds ( the truck isn't road legal yet)

Do you guys use any form of sound proofing on your transmisson tunnels/ seat boxes?

Without the seat box the transmission sounded like this (Sorry its not the smallest of files):


Maybe worth dropping the props and trying a similar exercise now everything is boxed up

Cheers for the Feedback


...Oops forgot to say that was running in 5th gear

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I got no significant change in transmission noise levels when I swapped to an lt77.

With the series overdrive gone I had no benefit from lower engine revs.

Yes I use non absorbent thick rubber matting on floor and seat box,and wear sponge ear plugs if on a long drive!

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  • 3 weeks later...

This is an oblique answer to the original question, but what you need are noise cancelling ear protectors.

These won't be the only ones, but look at http://www.noisebuster.net/nb-safety.htm

You will see they also do a unit with a radio in, although to be honest, this seems like self-induced Tinnitus to me.

Other people, like Bose, sell more upmarket versions, sized, styled and priced for different circumstances, such as travelling by airline.

I have a set, made by someone I forget, and bought from UK Maplin, for use in the office, to cut down the backgroung noise inherent in an open plan office. Very useful when I'm on long Audio Conferance calls.

The technology does seem like 'magic' or even snake oil, but it does work. Note that these units are powered, the anti-noise generator needs a battery.

Good Luck.

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Further to that answer, these days there are some blummin' cunning tuned ear protectors / plugs that block background machinery noise and let conversation through - something to do with the absorption properties of the materials they use. I know Zuz had some in the 109 in Russia and she was well pleased - she could clearly hear me talking over the racket the 109 makes, unfortunately I couldn't hear her quite so well :rolleyes:

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