# 2.5L Six Speed Swap



## DRGraphix (Jun 7, 2008)

OK, my MKV Jetta's 5 speed manual is dead, and I've found a GTI 6 speed with all associated hardware. If the trans fits, it's a simple swap. Has ANYONE actually tried this? I've spent all night searching this and other forums with no actual confirmation (although there's some talk...)


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## sl33pyb (Jan 15, 2007)

do it!!! i would consult a vw tech. audia4 might know


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## spitpilot (Feb 14, 2000)

*Re: (sl33pyb)*

Since the engines are not on a common block (like the ol VW 4 cylinder 1.8L, 2.0L, 16V etc etc were) I'd bet that its not just bolt it up and away you go like tranny swaps were for most of those engines!


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## Audi4u (Jun 29, 2002)

The bolt pattern should be the same.


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## DRGraphix (Jun 7, 2008)

Cool! what about the 5 cylinder engine being longer than the 2.0t? The most important concern here is that the length of the motor could push the trans closer the the passenger side and screw up the spacing of the driveshafts.
Also, do you think I need new hubs, or will the driveshafts work with my existing ones?


_Modified by DRGraphix at 8:38 PM 7-14-2008_


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## Audi4u (Jun 29, 2002)

*Re: (DRGraphix)*


_Quote, originally posted by *DRGraphix* »_Cool! what about the 5 cylinder engine being longer than the 2.0t? The most important concern here is that the length of the motor could push the trans closer the the passenger side and screw up the spacing of the driveshafts.
Also, do you think I need new hubs, or will the driveshafts work with my existing ones?

_Modified by DRGraphix at 2:05 PM 7-14-2008_

It's not as long as you think, and the difference in length is pushed to the passenger side.
If you use the 6spd axle you will need the matching hubs. you should contact user: undergroundvwparts they sell swap packages.


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## DRGraphix (Jun 7, 2008)

Ok, I'm a little confused, there is a difference? How does it end up being a simple swap then? How are stock parts going to compensate for that difference? 
Did you mean that the difference is pushed to the driver's side? That's the only way the longer block could mate to the GTI trans. with stock axles, right?


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## Audi4u (Jun 29, 2002)

*Re: (DRGraphix)*


_Quote, originally posted by *DRGraphix* »_Ok, I'm a little confused, there is a difference? How does it end up being a simple swap then? How are stock parts going to compensate for that difference? 
Did you mean that the difference is pushed to the driver's side? That's the only way the longer block could mate to the GTI trans. with stock axles, right?

think about it as in the same way you can swap a vr6 in the older cars. the drivetrain stays in the same spot. the longer the engine the closer it gets to the passenger side frame rail. 
Do you get what I'm trying to say?


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## DRGraphix (Jun 7, 2008)

Yes, I understand that. I've been told several times that the stock GTI driveshafts will work with this swap. I'm wondering how this is possible if the 2.5 engine is pushing the transmission further over than in the GTI. The only way this makes sense to me is if the longer engine is moved a bit to the driver's side.


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## Audi4u (Jun 29, 2002)

*Re: (DRGraphix)*


_Quote, originally posted by *DRGraphix* »_Yes, I understand that. I've been told several times that the stock GTI driveshafts will work with this swap. I'm wondering how this is possible if the 2.5 engine is pushing the transmission further over than in the GTI. The only way this makes sense to me is if the longer engine is moved a bit to the driver's side.

you mean the passenger side right?


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## DRGraphix (Jun 7, 2008)

*Re: (Audi4u)*








You're absolutely right, I haven't had this car on me for a while, and I'm a bit dyslexic. My other car is RWD, that's the hood I've been under recently.








Geez.....


_Modified by DRGraphix at 2:07 AM 7-15-2008_


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## Audi4u (Jun 29, 2002)

*Re: (DRGraphix)*

no worries. I was going to attempt the swap, but didn't have the money for it.
It would be cool to see it done.
you would basically need at least.
flywheel (and bolts)
clutch
pressure plate (and bolts)
slave cylinder hose
starter
axles
trans mount
and trans.


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## DRGraphix (Jun 7, 2008)

Yeah, undergroundvwparts said that there's also a thin plate between the engine and transmission. My Bentley manual is in the mail. I can't wait to see some diagrams. Your advice and lots of others have confirmed it'll work, so I'm going to buy the kit from the guy as long as it looks good in pictures.


_Modified by DRGraphix at 1:05 AM 7-16-2008_


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## maloosheck (Oct 5, 2004)

*FV-QR*

Are you still working on this project? I am going to swap 5MT -> 6MT in my TDI and I am interested in any of your findings. Also, did you find all the parts you need?


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## maloosheck (Oct 5, 2004)

*Re: (Audi4u)*


_Quote, originally posted by *Audi4u* »_you would basically need at least.
flywheel (and bolts)
clutch
pressure plate (and bolts)
slave cylinder hose
*starter*
axles
trans mount
and trans.

Are you sure 6MT and 5MT uses different starter?


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## Audi4u (Jun 29, 2002)

*Re: (maloosheck)*


_Quote, originally posted by *maloosheck* »_
Are you sure 6MT and 5MT uses different starter?

99.5% sure


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## Lower it!! (Aug 1, 2007)

*Re: (maloosheck)*

I so wanna do this. Stupid weak 2.5 ****. 3rd CV FTL! 
And I want a highway gear.


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## shipo (Jan 3, 2006)

*Re: (Lower it!!)*


_Quote, originally posted by *Lower it!!* »_And I want a highway gear.









The Rabbit/Jetta 5-Speed to the GTI/GLI 6-Speed won't get you that "highway gear". Why? Because the 5-Speed unit mounted to the 2.5 liter cars actually has a _taller_ top gear - final drive gear ratio than does the 6-Speed (although not by much).


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## CandyWhabbit (Sep 14, 2007)

*Re: (shipo)*

damn something i been wondering if it can be done for a long time. how much would this cost..estimate?


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## maloosheck (Oct 5, 2004)

*Re: (CandyWhabbit)*


_Quote, originally posted by *CandyWhabbit* »_damn something i been wondering if it can be done for a long time. how much would this cost..estimate?

based on the junk yard prices probably between $2k and $2.5k...


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## shipo (Jan 3, 2006)

*Re: (CandyWhabbit)*

Other than the fact that the 5-Speed unit seems to be a bit fragile (broken cases and such), I'm trying to figure out why someone would think it would be an advantage to do a 6-Speed swap. In the end I'm thinking that it would be better-faster-cheaper to trade the car for a car that already has a 6-Speed in it.


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## bunnyhopin (Dec 19, 2007)

*Re: (shipo)*

why not just change the gears in our 5 spd's? ... anyone try that yet?


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## maloosheck (Oct 5, 2004)

*Re: (bunnyhopin)*


_Quote, originally posted by *bunnyhopin* »_why not just change the gears in our 5 spd's? ... anyone try that yet?

5th gear conversion is pretty common exercise for diesels. Check out forums at tdiclub for details.


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## cyclegrip (Dec 3, 2006)

*Re: (shipo)*


_Quote, originally posted by *shipo* »_
The Rabbit/Jetta 5-Speed to the GTI/GLI 6-Speed won't get you that "highway gear". Why? Because the 5-Speed unit mounted to the 2.5 liter cars actually has a _taller_ top gear - final drive gear ratio than does the 6-Speed (although not by much).

To me it seems like VW didn't compensate for the % that the speedometer is off. I cruise at 70 and I know its only 65, and I am close to 3000 rpms. I would imagine if I cruised at 2.5 or less going the same speed, I would get better gas mileage, no?


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## maloosheck (Oct 5, 2004)

speedo sensor is at the wheel. nothing to do with the tranny.


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## shipo (Jan 3, 2006)

*Re: (cyclegrip)*


_Quote, originally posted by *cyclegrip* »_
To me it seems like VW didn't compensate for the % that the speedometer is off. I cruise at 70 and I know its only 65, and I am close to 3000 rpms. I would imagine if I cruised at 2.5 or less going the same speed, I would get better gas mileage, no?

I'm not sure what you're getting at, VW posts all of their gear ratios on their web site under the *Specifications* for the cars, and in order of the tallest top gear ratios to the shortest, the cars are as follows:
Engine RPMs:Wheel RPMs
2.61:1 -- Rabbit 6-Speed automatic
2.81:1 -- Rabbit 5-Speed manual
2.87:1 -- GTI 6-Speed manual
2.89:1 -- GTI 6-Speed automatic


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## DRGraphix (Jun 7, 2008)

Just bringing this back for anyone interested: Yes it works, but you have to be careful. For the last 10 years, I've driven with a 2007 GTI 6 speed (02J, please correct me if I get that wrong, it's been a while) mated to a 2007 BGQ motor, and it's all perfectly reliable. The biggest mistake I made was to not grind down the front top edge of the transmission. Repeat: If you want to install this transmission onto a 2.5, you MUST grind down the top edges of the transmission to avoid an oil leak. It's just a big solid chunk of aluminum with slightly conflicting machining tolerances, so the grinding hurts nothing.

When you don't grind that edge, all the parts visibly line up perfectly, but once you finally torque the bolts, the sharper edge of the transmission presses against the rounder recieving edge of the chain cover, and you'll hear a pop, but with no visible damage. For me, that pop was a small crack in the chain cover, which caused an oil leak, which wasn't apparent until a few weeks after it's all buttoned up. Since the chain is isolated from the block, there is no affect on vaccuum, and the leak is only coming from the spot just under the filler cap.

Weeks after the install, once I discovered the oil on top of the transmission, eventually making it to the exhaust manifold, I was able to patch 99% of the leak with permatex rtv. I still have to hose it down in a pressure wash, or get underneath with parts cleaner about twice a year, but for an oil leak, it's one of the least pressing you can have. I purchased a new chain cover, which I'll eventually install when I replace the clutch, AND grind that transmission edge. Judging by pictures, VW used the same chain cover on the CB_A engines, so I assume you must grind with all 2.5's.

Another big mistake you can make is throwing away the transmission bolts, like the seller of my transmission did. You have to mix and match between the trannies, so I spent a lot of time measuring the depth of bolt holes and discussing back and forth with my parts guy to ensure I made the right choices. It's MUCH easier if you have all bolts sitting there waiting to be mixed up.

Aside from those issues, it's pretty smooth sailing. The GTI flywheel and clutch bolt right in. Although the slave cylinder is in the trans, it has the same connection. This tranny is significantly heavier, and will be difficult for smaller people to lift. It's not just one more gearset, it's a whole other shaft of gears. This trans was used in pretty heavy duty applications, and has been absolutely bulletproof. The shift box and cables are identical, I don't think I even had to adjust the lengths. As I recall, the bracket that holds the cables fastens with one less bolt than intended. Obviously, after 10 years that's ok. I think the 5 speed had a flat steel plate between it and the transmission, which the 6 wouldn't fit. I left it out, and all seems well (again, forgive 10 year old memories).

Speed sensors and such are in the wheel hubs, not the transmission, so I never had any issues there. My 2005.5 has never recieved the ecu flash that corrects it's timing, so I've always had the speedo read slightly fast and the clock run slightly slow. That has nothing to do with this swap, but it still makes me laugh considering the rest of the car is so precisely designed. I think I'll finally get an ecu flash tool to get rid of the throttle lag, but aside from that, I'm just waiting for the clucth to go out to make this a perfect swap, finally ending my oil cleaning pennance. I lucked out just after putting the trans in, ECS put the (usually expensive) golf ball 6-speed knob on clearence for dirt cheap. It stil looks great after 10 years, with some wear.

Now, I'm also wondering about my 2007 motor's timing chain. It's not a CB_A engine, but that year seems to have the least amount of reports of jumped chains. What do you guys think?


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