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5 to 6 speed gearbox conversion GTI


Cootem
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Hi everyone,

i have been offered a 5 speed lupo GTI for a good price and the only problem is the 5 speed gearbox has a whine in 3rd.

i have been looking at reconditioned gearboxes and was wondering if it is possible to put the 6 speed gearbox on? And if so what else would have to be changed such as gear linkages? and will it work with the current ecu?

i have searched on the forum for this question and haven't been able to find a definitive answer. i know the 6 speed lupo box will not fit to a 5 speed polo gti but what about the 5 speed lupo gti?

thanks in advance

matt

Edited by Cootem
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No a Polo gearbox won't fit. The 5 speed GTI box is basically the same as the 6 speed, just without 6th gear (which the bolted onto the end of the gearbox case!). I'm not sure what would be involved with going from 5 speed to 6, I think its the linkages that are slightly different, so if you bought a 6speed with all of that, I don't see why it wouldn't work.

Edited by lupogtiboy
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  • 6 years later...

Did anyone get anywhere with this?  I'm about to put my newly aquired 6-speed in my 5-speed GTi.  I can't imagine any issues, other than the fact the final drive is definitely different and so my speedo may need adapting to the 6-speed box!

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On 1/14/2022 at 10:27 AM, Rich said:

Not even that.

Bolt in and go.

Good to know Rich, thanks for that.  The box is being split by my local transmission guy to have a looksee at the condition before I throw it in.  He said it's all on the original OEM seals so probably hasn't had a service since 2002.  You mentioned about using TSi parts to upgrade - what would these parts be and off which vehicle?

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If it's all good inside once split into 2 halves, the bearings to replace easily/quickly would be the diff and pinion bearings. And the 2 diff flanges, the input shaft and shifter seals. I'd stay well clear of the 5/6 cover as that is the weakest part of the system (the cover moves and then it's game over). The 6th gear cog is supported by an additional (afterthought) bearing mounted in the cover. Use 6th as a cruising gear with low torque- don't cane it in 6th. 👍🏻

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Thanks for the tip mk2.  You say stay clear of the cover - as in, don't even take it apart?  Wouldn't the bearing in the cover not be a viable thing to renew if it's placed under a lot of lateral load?  Would you know anything about upgrade parts to renew?

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On 1/18/2022 at 8:34 PM, cpcpeter said:

Thanks for the tip mk2.  You say stay clear of the cover - as in, don't even take it apart?  Wouldn't the bearing in the cover not be a viable thing to renew if it's placed under a lot of lateral load?  Would you know anything about upgrade parts to renew?

from my experience replacing these bearings is a piece of cake with the right tools, mk2 is correct regarding the alignment of the bearings but a gearbox man should know what hes doing, removing the 6th gear is not possible without damaging a syncro in the process, this increases built costs £50 ish, FYI

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I told my gearbox man about 6th gear and he said it's possible to remove without hacking the synchro - just have to know what to do apparently!  When he next calls I'll have to ask what parts can be upgraded on the original box.  I don't intend to get this serviced (other than oil changes) for the next 10 years!

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On 1/21/2022 at 7:29 AM, cpcpeter said:

I told my gearbox man about 6th gear and he said it's possible to remove without hacking the synchro - just have to know what to do apparently!  When he next calls I'll have to ask what parts can be upgraded on the original box.  I don't intend to get this serviced (other than oil changes) for the next 10 years!

I thought the same until it came to doing it, hopefully I’m wrong let us know how you get on, upgraded parts would also be nice to know

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It'll be obvious if the box is still in good condition when you split it. Seriously, I'd not touch that cover if there's nothing wrong. Just do the 3 bearings that get the most stick. Diff and pinion.

The condition of the pinion bearing on the output shaft is the 'tell tale'. A bit of wear is fine, but if there's any deep scoring or grooves, then do a full rebuild. Also check the magnet to see how much white metal it's collected over the years. Also worth checking the contact teeth on the brass synchro cones to see if they need swapping. 2nd and 3rd are usually the ones that wear the quickest.

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  • 4 months later...

By way of update, that’s my gearbox man finished upgrading the 6-speed box. Turned out it was in need of an input shaft bearing at the minimum but all seals and bearings bar the 5/6 end casing bearings were changed. Very little filings on the magnet and otherwise healthy. 
 

The ‘box had the Quaife transplanted from my 5 speed too with new ARP bolts. They were orientated upwards in the end with the casing machined to make room. The other way would not have allowed the bolts’ splined segment to properly dig into the softer metal on the other side so it’s in a stronger position this way. Also, 6th gear synchro did not have to be broken at any point. 

Finally, a note on the 5/6 bearings in the end casing. My gearbox man has seen many issues like this with the VW end gears prematurely wearing with bearings and it’s usually due to lack of oil rather than the casing being disturbed. There is a sealed baffle separating the compartment where 5/6 gears, end bearing and end case reside. The only way oil can get in is by angling the box as it’s being “factory” filled. Failure to do this will result in premature wear and most likely be the cause of those end bearings failing. I’ve actually had the baffle modified and a lower oilway has been machined so that whenever I fill up the oil at the diff casing, the level will be perfect across the whole box. This should hopefully reduce the chance of those bearings failing. 

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