5th gear problems - advice needed

crdouger · Oct 9, 2018

My brother's 02 mkiv with 260k miles broke it's 5th gear recently. It still drives great in the other gears, but 5th just spins and grinds and goes nowhere. In a month he plans to drive the car 3 hours up to my house in 4th gear and then we plan to spend the weekend fixing it together. I'm considering two options and I'd like some advice as to which is wisest:

1) Buy a new 5th gear set (.658) and replace the gears. I've never done this, but I've watched videos and it seems within my skill set. But I'm worried if there are additional splines stripped or problems from chunks of metal floating around while he continues to drive it. I don't want to buy the 5th gear set and then find out more is broken when he get's the car here. How probable is it that more is broken?

2) I have a lead on a used transmission and then buy a new clutch and swap it out. It seems like more work to completely drop the transmission and replace it, but if we work hard then we should be able to get the job done in a weekend.

Advice?

Thanks in advance.

Crdouger

jokila · Oct 10, 2018

crdouger said:
My brother's 02 mkiv with 260k miles broke it's 5th gear recently. It still drives great in the other gears, but 5th just spins and grinds and goes nowhere. In a month he plans to drive the car 3 hours up to my house in 4th gear and then we plan to spend the weekend fixing it together. I'm considering two options and I'd like some advice as to which is wisest:
1) Buy a new 5th gear set (.658) and replace the gears. I've never done this, but I've watched videos and it seems within my skill set. But I'm worried if there are additional splines stripped or problems from chunks of metal floating around while he continues to drive it. I don't want to buy the 5th gear set and then find out more is broken when he get's the car here. How probable is it that more is broken?
2) I have a lead on a used transmission and then buy a new clutch and swap it out. It seems like more work to completely drop the transmission and replace it, but if we work hard then we should be able to get the job done in a weekend.
Advice?
Thanks in advance.
Crdouger

You are going to want to take the cover off and inspect. It could be the pawls on the shift selector fork are worn instead of the gear.

steve6 · Oct 10, 2018

Most of the time if you've got to a point where its stripped there is other damage related to the gears, best to have a transmission ready to go if you need to drop and replace.. drop and replace isn't too bad with multiple people, depending if you need to change clutch or not.

crdouger · Oct 10, 2018

If we end up dropping the transmission, we might as well replace the clutch. The car has 260,000 miles and the clutch is unknown to us. If we repair it, where do people recommend buying a taller gear (.658) from? idparts has one for $450 and ebay for $270.

I'll see if there is a way for me to get the car earlier and get the cover taken off to inspect it and see what I can learn. Thanks for the advice and suggestions.

ToxicDoc · Oct 10, 2018

crdouger said:
If we end up dropping the transmission, we might as well replace the clutch. The car has 260,000 miles and the clutch is unknown to us. If we repair it, where do people recommend buying a taller gear (.658) from? idparts has one for $450 and ebay for $270.

I'll see if there is a way for me to get the car earlier and get the cover taken off to inspect it and see what I can learn. Thanks for the advice and suggestions.

Bought a set of .700 gears earlier this year from Kerma, and I've been happy with them. The rpm drop from 4 to 5 makes me glad I didn't go with anything larger (numerically lower). I don't see how people like the .658 gears.

BobnOH · Oct 10, 2018

I've read it's not hard to swap out gear 5, but I've also read there are some related bits that may want replaced. Like jokila says, a good inspection is in order.
There are some good threads on the swap.
VW TDI Search Engine

Be careful what you find at ebay/amazon/alibaba, be sure you know exactly what it is you're purchasing.

Rob Mayercik · Oct 10, 2018

Might be better to plan on just swapping in the used trans, and examining the broken one on the bench where it can't prevent the car from being driven before committing to buying repair parts.

That isn't to say that you can't go ahead and fix this one either as a spare or a backup anyway...

oilhammer · Oct 10, 2018

In about as much time as it takes to read this thread, you can have the side cover off the gearbox and SEE what you need to replace.

I actually had a crappy rebuild one in here not long ago that had the splines on the output shaft where the 5th driven gear rides stripped out.

Rrusse11 · Oct 10, 2018

I had a .658 and had it swapped out for a .717 5th. MUCH better, I can now cruise at 65-70mph with the engine circa 2200 rpm.

The drop in rpm is now ~800-900 4th>5th, much more driveable and keeps the turbo working when I shift in the low 3krpm range. I got it from ebay, a UK vendor. My tranny guy, who is a dyed in the wool OEM guy, said the quality on the Italian build gear was excellent.

When I have the roads, the car just loves 80mph. A nice overdrive 5th without being over the top, which I certainly found the .658 to be.

My $.02,
R*2

PakProtector · Oct 10, 2018

oilhammer said:
In about as much time as it takes to read this thread, you can have the side cover off the gearbox and SEE what you need to replace.

I actually had a crappy rebuild one in here not long ago that had the splines on the output shaft where the 5th driven gear rides stripped out.

That 5th gear has NV4500 topology written all over it. It must be done better 'cause I see very few wrecked ones...

OTOH, there is no litre/cylinder I-6 delivering full torque to it at 1600 rpm either.
cheers,
Douglas

Hyde7278 · Oct 11, 2018

There has been a few treads where the splines get stripped off. Caused by lugging the car in 5th gear.

Some have been able to temp fix by using green loctight I believe.

5th gear problems - advice needed

crdouger

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jokila

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steve6

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crdouger

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ToxicDoc

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BobnOH

not-a-mechanic

Rob Mayercik

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oilhammer

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Rrusse11

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PakProtector

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Hyde7278

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