The Gearbox & Diff thread

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spetz
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Re: The Gearbox & Diff thread

Post by spetz »

How do you know if/when your bearings need changing?
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Re: The Gearbox & Diff thread

Post by Sahin »

crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch crunch
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Re: The Gearbox & Diff thread

Post by silverGPX »

And whirring/vibration
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Re: The Gearbox & Diff thread

Post by spetz »

Will it crunch, or is that only when synchros are worn?
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Re: The Gearbox & Diff thread

Post by Bennoz »

It actually sounds clunky at idle. You hear a whirring-knocking sorta noise coming from the gearbox, put your foot on the clutch & it goes away (sorta like a thrust bearing failure) as when your foot is on the clutch, no part of the box is moving (assuming your at a stop.)

The first bearing to go on every single FTO box is the primary input shaft bearing. Ie the one closest the clutch, the one that you test by trying to wiggle the shaft that goes into the gearbox. It's the first to cop the torque load from the motor.

Primary shaft - Engine side x1
NSK Roller Ball Bearing
NSK B25-157 (B25-157Aa)

As far as I'm concerned, its an under spec bearing. It should have been something better, such as a barrel roller. Because every box I reco, this bearing is fucked.
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Re: The Gearbox & Diff thread

Post by Bennoz »

spetz wrote:Will it crunch, or is that only when synchros are worn?
Generally, yes.
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Re: The Gearbox & Diff thread

Post by spetz »

Thanks Bennoz for the explanation.
is there a need for machined etc when you do a reco?
And how much time does it take you to recondition a gearbox?
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Re: The Gearbox & Diff thread

Post by Bennoz »

spetz wrote:Thanks Bennoz for the explanation.
is there a need for machined etc when you do a reco?
And how much time does it take you to recondition a gearbox?
No, not really anything to machine. All the tolerances in the box are governed by a range of thick cir-clips. As they wear, there's a range of different thickness replacements you can order depending on the thickness you need. On the diff, it's just a simple shim. Again, different thickness shim are available based on what you measure up.

A problem free reco, usually takes me about 4 hours to do.
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Re: The Gearbox & Diff thread

Post by aza013 »

Bennoz wrote:It actually sounds clunky at idle. You hear a whirring-knocking sorta noise coming from the gearbox, put your foot on the clutch & it goes away (sorta like a thrust bearing failure) as when your foot is on the clutch, no part of the box is moving (assuming your at a stop.)

The first bearing to go on every single FTO box is the primary input shaft bearing. Ie the one closest the clutch, the one that you test by trying to wiggle the shaft that goes into the gearbox. It's the first to cop the torque load from the motor.

Primary shaft - Engine side x1
NSK Roller Ball Bearing
NSK B25-157 (B25-157Aa)

As far as I'm concerned, its an under spec bearing. It should have been something better, such as a barrel roller. Because every box I reco, this bearing is fucked.
Hum sounds like my one may need doing after reading that, as its just starting to make some of them sounds lol.
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Re: The Gearbox & Diff thread

Post by Supplanter »

What it be possible for you to fit a more suitable replacement bearing?
LED ALL the things.
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Re: The Gearbox & Diff thread

Post by Taz »

My 98 GPR has a Helical LSD in it - if it somehow matters to your research the end serial is WR4616 :)
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Re: The Gearbox & Diff thread

Post by Gholdwayne »

Anyone know if the F5M42 syncros can be acquired locally?
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Re: The Gearbox & Diff thread

Post by Astron_Boy »

Gholdwayne wrote:Anyone know if the F5M42 syncros can be acquired locally?
Bennoz.


And Gholdy! you AWOL prick! :lol:
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Re: The Gearbox & Diff thread

Post by Gholdwayne »

Ah ok, hopefully Bennoz will sell/give me some...

Yeah man, mostly communicating on facebook and been in another planet pretty much :|


But yeah, sent my car in to a transmission specialist mechanic to:

- Replace gearbox bearings
- Put in Exedy HD clutch
* Might also tell them to replace the rear main seal?

I just thought, might as well replace the syncros, they're not too bad - but should I? The gearchange crunches are very occasional anyway...
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...and when im not, im looking at her!
... ...and when im not, im freakin thinking about her!

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Re: The Gearbox & Diff thread

Post by Storm »

Slightly different question but does anyone know the final drive ration of the different boxes used in Mivec, non Mivec and LSD boxes?
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Re: The Gearbox & Diff thread

Post by Shhtuart »

Storm wrote:Slightly different question but does anyone know the final drive ration of the different boxes used in Mivec, non Mivec and LSD boxes?
gearratios.jpg
gearratios.jpg (158.23 KiB) Viewed 1412 times
That's all i could find, I don't see how the LSD boxes would have different gear ratios?
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Storm
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Re: The Gearbox & Diff thread

Post by Storm »

Shhtuart wrote:
Storm wrote:Slightly different question but does anyone know the final drive ration of the different boxes used in Mivec, non Mivec and LSD boxes?
gearratios.jpg
That's all i could find, I don't see how the LSD boxes would have different gear ratios?
I don't know about the LSD boxes but it would appear that Mivec and non-Mivec cars have (probably not every one of them but mainly) different differentials, as noted by the different tripod joint sizes. there is also a conception that non-Mivec boxes are better for acceleration.

I don't think Mitsi would have put different gear ratios for every gear but it does seem like the diffs are different so I assume their final drive ratios could be different to take into account the extra few horse power that Mivec kicking in would bring.

Or not, as the case may be!
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Re: The Gearbox & Diff thread

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Storm wrote:there is also a conception that non-Mivec boxes are better for acceleration.

I assume their final drive ratios could be different to take into account the extra few horse power that Mivec kicking in would bring.

Or not, as the case may be!
Correct, they are slightly different between Mivec and non mivec.

Theres a Bennoz quote about it buried somewhere. Cbf looking at 2am.
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Re: The Gearbox & Diff thread

Post by Storm »

Daniel2019 wrote: Cbf looking at 2am.
Don't blame you, time difference from Scotland makes for drawn out conversations! lol
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Re: The Gearbox & Diff thread

Post by Daniel2019 »

Storm wrote:
Daniel2019 wrote: Cbf looking at 2am.
Don't blame you, time difference from Scotland makes for drawn out conversations! lol
Still cbf and its 10:45am.. :lol: :geny: :lawso:

Although im 99% sure there isnt a difference between LSD and non-LSD models. I dont see why there would be. Just mivec/non mivec boxes.

Edit: Dammit, :lawso: isnt the little cletus gen-y emoticon :(
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