02j question

Twitch

Well-known member
Joined
Apr 24, 2017
Location
New jersey
TDI
2003 gls jetta tdi 5 speed
Hello i have a 2003 jetta alh 5 speed and i am currently redoing the car and changing out all the fluids so i know everything is fresh and the cars reliable. I am trying to a manual transmission oil. I went to my local advance auto parts and found the pennzoil synchromesh 75w-90 gear oil but it has a gm and chrysler recommendation nothing about vw and is rated for gl-3 spec not gl4. I usually just go with mobile 1 but that is a gl5 fluid. The vavoline they had on the shelf was a gl4-gl5 fluid is that okay to use or will cause damage i am already in the car alil deeper then i wanted to be at the moment and dont feel like rebuilding the trans or finding a new trans cause the oil wrecked the synchro’s. Thanks for all the help in advance
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
You don't want a GL5 - too thick for that transmission.

GM syncromesh is a great fluid for 02J's and 02A's. I ran it in my 99.5 jetta for 200k and no issues. Made shifting smoother as well.

A lot of folks here run it as well.
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
WARNING!

Do not EVER put a GL-5 oil in a manual transmission UNLESS it is specifically placarded for it by the manufacturer, and essentially NO gearboxes are.

You will DESTROY the synchros.

The reason for this is that GL-5 EP additives (the chemical package in the oil that resists gear wear) works, as do all such packages, by depositing on the surfaces in the unit. The film strength is weaker than the metal and thus shears first, protecting the metal.

The problem is that GL-5's package is STRONGER than the shear strength of the synchros! As a result the synchros will shear (wear) instead of the deposited film on them which is exactly the opposite of what you want to happen.

The (relative) dearth of MTX boxes over the last couple of decades has made GL-4 lubricants harder to find. If the label has BOTH specs on it then you still CANNOT use it; you must have a lubricant for a MTX in nearly all cases that does NOT have the GL-5 certification anywhere on the label.

Redline makes a suitable oil (MTL) and then of course there are the "official" VW oils as well. Synchromesh is a potential choice but it is IMHO not the best option; it is a very light oil comparatively (viscosity wise); I prefer the Redline MTL as it has better physical properties. It can be somewhat difficult to find locally but there's always getting it off the Internet.

GL-5 full-synthetics (e.g. Mobil 1) are great for differentials OTHER THAN THE OLDSTYLE POSI-TRACKS which have the same basic issue as does an MTX. The "roller locking" style ones found in trucks, for example, are fine with a GL-5 and in fact it's considered "required" in many applications.

But never, ever put an oil with GL-5 on the label in a MTX without a SPECIFIC recommendation to do so by the manufacturer unless you wish to tear it apart and replace the synchros at some point in the future.

VW's "official" oil is G070, which if I understand things correctly is quite light in viscosity, but it's what I've been using in my '03 without complaints. I have Redline MTL in my Mazda and like it, other than being rather notchy in VERY cold conditions (e.g. below zero outdoors overnight) until things warm up a bit.
 
Last edited:

Judson

Veteran Member
Joined
Jan 18, 2001
Location
Cheyenne, WY
TDI
2001 Jetta
I second Windex's post: GM Syncromesh has worked best in my transmission. G50 and especially G70 were inferior. Last time I tried Redline MTL my hair wasn't grey. Glad to hear they're still around!
 

Windex

Top Post Dawg
Joined
Apr 1, 2006
Location
Cambridge
TDI
05 B5V 01E FRF
WARNING!

Do not EVER put a GL-5 oil in a manual transmission UNLESS it is specifically placarded for it by the manufacturer, and essentially NO gearboxes are.

You will DESTROY the synchros.

The reason for this is that GL-5 EP additives (the chemical package in the oil that resists gear wear) works, as do all such packages, by depositing on the surfaces in the unit. The film strength is weaker than the metal and thus shears first, protecting the metal.

The problem is that GL-5's package is STRONGER than the shear strength of the synchros! As a result the synchros will shear (wear) instead of the deposited film on them which is exactly the opposite of what you want to happen.

The (relative) dearth of MTX boxes over the last couple of decades has made GL-4 lubricants harder to find. If the label has BOTH specs on it then you still CANNOT use it; you must have a lubricant for a MTX in nearly all cases that does NOT have the GL-5 certification anywhere on the label.

Redline makes a suitable oil (MTL) and then of course there are the "official" VW oils as well. Synchromesh is a potential choice but it is IMHO not the best option; it is a very light oil comparatively (viscosity wise); I prefer the Redline MTL as it has better physical properties. It can be somewhat difficult to find locally but there's always getting it off the Internet.

GL-5 full-synthetics (e.g. Mobil 1) are great for differentials OTHER THAN THE OLDSTYLE POSI-TRACKS which have the same basic issue as does an MTX. The "roller locking" style ones found in trucks, for example, are fine with a GL-5 and in fact it's considered "required" in many applications.

But never, ever put an oil with GL-5 on the label in a MTX without a SPECIFIC recommendation to do so by the manufacturer unless you wish to tear it apart and replace the synchros at some point in the future.

VW's "official" oil is G070, which if I understand things correctly is quite light in viscosity, but it's what I've been using in my '03 without complaints. I have Redline MTL in my Mazda and like it, other than being rather notchy in VERY cold conditions (e.g. below zero outdoors overnight) until things warm up a bit.
Did some research a while back and pulled the viscosities of a number of fluids as pulled from various threads and manufacturer sites:

CsT is centistokes, and is a measure of fluid thickness (viscosity), measured at 40 degrees C and 100 degrees C

--------------CsT@40 deg c-- CsT@100deg c
VW G70-------------- 31-------- 6.2
Fuchs Titan sintofluid- 41-------- 6.7
Penz(GM) syncromesh 41.6 -------9
Amsoil Syncromesh ---48.3 -------9.7
Redline MTL 70W80 ---56.2 ------10.6
Redline 75W85 -------64.3------- 12
Motul: 5.2 75W90 ----72.6 -------15.2
Mobil1: 75W90 -------99 ---------15.2
Redline MT-90:75W90 106 --------15.6
R. Purple: 75W90 ----119 --------17.5
Lucas: 75W90 ------ 142 --------18.4

Odd that you're concerned about Syncromesh being too thin yet running a fluid far thinner? :confused::rolleyes:
 

Genesis

Top Post Dawg
Joined
Feb 26, 2003
Location
Sevier County TN
TDI
'03 Jetta Wagon
Viscosity isn't the whole story by a long shot.

My Mazda runs 0w20 oil yet puts up wear numbers (Al 2ppm, Fe 4ppm, Cu and Pb 1ppm) over a full interval that are head-scratchingly impossible with older formulations and engine designs.

Engines (and gearboxes) are designed with specific clearances and with specific viscosity and other physical parameters (e.g. shear resistance, etc.) in mind. There are a whole range of conspiracy theories out there (e.g. that engine manufacturers trade wear protection for fuel economy, for example, in their recommendations) but without facts you're basically taking a conspiracy theory as gospel and using it to inform your decision without any sort of factual basis behind it. Over 120,000 miles of runtime on my Mazda with UOAs showing effectively zero internal parts wear while running the recommended 0w20 grade of oil from multiple manufacturers says that in *that specific* case the theories are bunk.

Anyone got evidence of an 02j being blown up due to running G 070 -- that is, some sort of internal failure or wear attributable to insufficient film shear strength? I've not heard of one and my '03 has roughly a quarter-million miles on it, it still shifts approximately as it did when it was new, and neither I or my daughter have detected any sort of problem, nor has the oil shown any evidence of trouble when changed (on 50-70k mile intervals since the vehicle was new.)
 

ffemtp

Veteran Member
Joined
Dec 9, 2008
Location
SE WI
TDI
2001 Jetta GLS TDI Deceased 11/2012, 2004 Jetta GL TDI Sold, 2012 Jetta TDI (Retruned to VW), 2004 Jetta TDI GLS 5spd
I did a fifth gear swap last year. Changed to a .658 ratio - nice upgrade. I refilled with Redline MT90. The transmission was notchy, and was not smooth by any means. Ran with it for about 1500 miles and drained it out. I went back to the VW Dealer and got the VW tranny fluid. It seemed to work better than the Redline - at least for my car. Happy car = happy owner!
 

Twitch

Well-known member
Joined
Apr 24, 2017
Location
New jersey
TDI
2003 gls jetta tdi 5 speed
Thank you for all your help today when i pick up my exhaust manifold gasket i will pick up 3 bottles off pennzoil syncromesh thank you for all the input
 

jimbote

Certified Volkswagen Nut
Joined
Jul 10, 2006
Location
spiral arm, milky way (aka central NC)
TDI
Tacoma 4x4 converted to TDI
FYI: valvoline brand synchromesh DOES meet vw specs for 02J and 02M ... i don't think it's much of a leap to say pennzoil would as well plus it has a great track record with users on here
 

02_TDI_FireMan

Well-known member
Joined
Feb 19, 2003
Location
Port Saint Lucie
TDI
03 Golf
At 200k miles at changed my gear box oil. Refilled with Mobil 1 75-90 synthetic. I am now at 407k miles with no known issues so far. It is time to drain and refill again ... decision decisions now .. lol I found this thread trying to research .658 5 th gear swap.
 
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