What Manual Transmission Fluid

I've been grinding going into second gear for about a year now - just been easing it into 2nd trying not to grind the gears. It's also been very hard to get it out of reverse after backing out the driveway. Then, for the last couple weeks, I started having problems going into 3rd, 4th, and 5th. Stiff shifting - not wanting to go completely into the gear. So, at 267k, I just thought my 2002 Jetta TDI was about due for a replacement tranny.

Decided to make sure the tranny was full of fluid, so I could only find some Mobil 1 and Lucas Oil gear lube in the garage. Wasn't sure which one to use so I read this thread and decided it top off the tranny with some Pennzoil Synchromesh. While I was buying a quart, I decided to buy 3 quarts and change the fluid completely instead of topping off.

WOW. ALL my shifting problems went away. All gears are very smooth shifting now. I'm very impressed.

Yup, my experience as well. Good stuff.

Was going to start a new thread but...

.. Figured I'll post here.

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

I have a slight crunch/grind going from 1st to 2nd gear only from cold. 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

Thinner oil is what you want. It's less of a thick and thin as to what makes synchros grab and more of the friction modifiers that are added to Manual Transmission Lube or Synchromesh Transmission Fluid.

Get G070 or GM Synchromesh and be done with it.

I can say that G070 has issues when hot. Shifting was fine in the cold, but during the summer, after a long trip (heated up trans), the g070 was getting notchy- which makes me think that it thins out too much- or the additives are not as flexible as the Syncromesh fluids.

I just wanted to thank everybody who contributed to this thread, as well as others, for the assistance in helping me to chose the oil to replace in our tranny. You see, I have been a bad boy where we purchased our 01 Jetta new, and I have been religious about other maintenance, but I never got around to changing out the tranny juice, where it is now 345,000 miles and 17 years later. With that, I was really surprised when I removed the plug that what came out was only slightly darker, clear and no part numbers, than the Pennsoil Syncromesh that I replaced it with? After a couple of hundred miles now it does shift noticeably easier and smoother.

Again, thanks everybody!

Bill