Stiff gear shifting when cold.

I'm in the UK and have a 2005 Mk5 Golf GT TDI 140 with a 6 speed gearbox.

My gear changes are stiff from cold and alsoI have a slight crunch/grind going from 1st to 2nd gear only from cold if I shift too quickly. Once warmed up it's beautiful no problem at all.

It's on 101k miles and only recently put the G052 gearbox oil in. I had hoped it would make a difference but it hasn't really.

I'm currently trying to figure out if using either a thicker or thinner gear oil would be beneficial.

I can see a thicker oil would slow down a gear change giving the syncros more time to engage and maybe give the syncros/cones a thicker coating of oil to grip with?

A thinner oil I can see would perhaps clear quicker as the syncro slides over the cone giving more metal to metal contact which may grip better?

Currently confused, thicker or thinner for a slight 1st to 2nd crunch when cold?

I wonder if using G060 or G070 might be better? Are they thinner oils?

Hope you can advise me folks! Thx!

Thinner
The only reason it shifts better when warm is because the fluid warms up.
Use some VW G070 fluid, which is thinner than G052.

I don't believe G070 is spec'd for use in the 6 speed.

Thinner oil would make sense. Would it get too thin though once warm?

G070 may not officially be spec'd for a 6 speed but could it actually "hurt" it

BLKGTTDI said:

Thinner oil would make sense. Would it get too thin though once warm?
G070 may not officially be spec'd for a 6 speed but could it actually "hurt" it

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It should be fine, others may disagree. I use G070 in our 2000 TDI 5 speed and GM synchromesh in my 1997 TDI 5 speed (which is thinner than G070).

I know my mk4, when stupid cold, is fussy to shift.. I just pay attention, and shift real easy. After 10mins.. good to go as normal.

If you pay attention to the shifting, does it shift 'ok', or is it bad regardless of how much attention you pay to the shifting?

CourierGuy said:

I know my mk4, when stupid cold, is fussy to shift.. I just pay attention, and shift real easy. After 10mins.. good to go as normal.

If you pay attention to the shifting, does it shift 'ok', or is it bad regardless of how much attention you pay to the shifting?

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Its not bad regardless no, I just have to shift 1>2 slowly from cold then like yourself.. After 10-15 minutes it's normal.

I double clutch on the 1-2 up shift the first five minutes on very cold mornings.

You don't have to tap the gas, just do the shift < 2000 rpm, lift and depress.the clutch in neutral, second comes in smooth and effortless.

I have a history of old Saabs with bad syncros. The gearboxes in the 96s and 99s were like the HPFP in our cars.

I had one vehicle (not a VW) with a 5-speed that had a cold-shifting problem. It was due to the fact that the previous owner had changed out the transmission oil to some awful 90W-140 sludge. The problem was resolved with GM Syncromesh. I changed the oil out twice and every couple of years thereafter, and I drove it from 70K to 150K (when I got rid of it) with no transmission troubles.
We, too, have a long history of SAABs, mostly used cars with a lot of miles, although we never had to work on a transmission. Some of those 900s and 9000s actually specified 10W-30 motor oil for the 5-speed.

Update

Put Pennzoil Synchromesh in tonight.

Drive home felt the same as normal (when warm) notchy but not grinding.

I suppose it'll take a few miles before it works it's way round the gearbox.

Sychromesh Friction Modified, might do better.

Jesus Is Lord said:

Sychromesh Friction Modified, might do better.

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The AC Delco Synchromesh Friction Modified?

I've read many good things about this oil, if the Pennzoil doesn't help I may give that a try next.

I don't really know what "friction modified" actually means. Modified to provide the synchro/baulk rings with more, or less friction...?

BLKGTTDI said:

The AC Delco Synchromesh Friction Modified?
I've read many good things about this oil, if the Pennzoil doesn't help I may give that a try next.
I don't really know what "friction modified" actually means. Modified to provide the synchro/baulk rings with more, or less friction...?

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Friction modifier reduces friction.

Jesus Is Lord said:

Friction modifier reduces friction.

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if the friction modified stuff reduces friction = more "slippery"

With that logic I would assume the non friction modified lube a better choice for Synchro rings to have more friction to allow them to "grab" and do their job.

BLKGTTDI said:

if the friction modified stuff reduces friction = more "slippery"
With that logic I would assume the non friction modified lube a better choice for Synchro rings to have more friction to allow them to "grab" and do their job.

Click to expand...

I don't claim to know how it works. All I know is, I put Friction Modified fluid in our two Jetta's and they shift a whole lot better.

I have ran both the GM FM and non FM fluid in Honda transmissions. It was my
Experience that they both work great.

My next MTL change will have me draining Motul Gear 300 75w90 which is a bit too thick in the cold temps in our winters -10c to -25c. I will be filling with Redline MTL most likely.

I think the GM syncromesh fluid is of a better quality than the Pennzoil one (maybe GM is a semi-synthetic or synthetic??). I only had notchiness with the FM version on a day of 4 F (-15C). Pennzoil IIRC years ago wasn't as good in the cold.

Hi guys,

I actually read most of this thread. I either missed it, or the info was not clearly stated. I have a 2006 Polo TDI BNV JCZ transmission. In 2007-2008, the car had a service action (as they call it), and they replaced the gear oil. Part number used: G052512S0. As I found out, this is an internal part number. We can buy it as G052512A2. At around 100k km, I bought gear oil from the dealer - part number G070726A2. At around 200k km - same part number. I didn't pay any attention to the part number. I thought they will sell me what the car uses...
What do you think I should buy now: G052512A2 or G070726A2. Does anyone know for sure the difference between the two?
I'm thinking about this because I have 2 different noises from the gearbox:
1. something like "hhhhh" when under 0C, at first start in the morning. it stops when the clutch is completely disengaged (everything in the gearbox stops). if it's only half, sound is still there. after 5-10 min of driving, the sound goes away. If over 10C, sound is not present.
2. after wellwarmed up gear box, when over 20C in the air, just before the car comes to a complete stop, so 1-2 km/h, it makes a knocking sound but not continuously - it's like the sound can be heard every 45 degrees of the wheel. car can stop and the noise may or may be not present ( depends on where the wheel or driveshaft stops). if the noise is present, it goes away if trying to engage 3rd or 4th gear without pressing the clutch, or if turning the steering wheel !! it also goes away gradually if pressing the clutch. if the car stops and the noise is not present, I can be heard if turning the steering wheel.
if there was a gearbox issue, why is it affected by the turning of the steering wheel?
the car has no abnormal noises when driven: hard accelerating, hard decelerating, turning hard uphill, breaking hard downhill and turning.
someone gave me the idea of checking the tapered coned bronze ring from the flanged output shaft that comes out of the diff, and when doing so, I will put fresh gearoil in. now, what should I use G052512A2 (the service action oil) or the G070726A2 (the oil that the dealer would sell me now according the VIN) ?

Thanks!

We hear a lot of stuff and I think maybe a little .pdf from someone who speaks knowledgeably on the subject would help everyone to better understand the difference between GL-4 and GL-5. It has to do with the 'friction modifiers' Sounds sexy, but doesn't always work. It has to do with the Sulfur/ Phosphorus additive and the amounts used. The element binds to part under heat and pressure. It's the black element sticking to all the gears.

The 'EP' versions, like GL-5 are hard on the synchronizers. The reason is that the sacrificial element is bonding too well to the brass synchronizer and is the element is stronger than the brass. The result is that the sacrificial element pulls microns of the brass each time it tears off, sacrificially.

http://www.widman.biz/uploads/Transaxle_oil.pdf

The GL rating is actually for transaxles, not transmissions. You can go off the reservation, but I see the newer oils can damage brass syncos, and eventually, the whole transmission.

If you are installing gear oil for the 02A or 02J transmissions, it should meet the GL-4 rating.

just put in G052512A2. Obvious smoother shifting (25 Celsius outside) cold and warm. I expect the lever to move like through honey in the winter for the first 10-15 min but I won't mind.
When I took out the filling plug (car leveled), about 100-150 ml of oil bursted out, so that confirmed my "suspicion" that I did overfill the gearbox, which is good .
When refilling, I tilted the car for about 10-15 degrees, and it took about 1.8 - 1.9L of oil before starting to overflow. Then I put the filling plug back in quickly so I guess I overfilled it also this time.

difference between G052512A2 and G070726A2: G052 seems to have a bit darker colour. At room temp, to the naked eye they seem to have the same viscosity.