Viscosity and notchy/crunchy syncho?

[TT'ed]

Hey everyone, I have some questions for people who prays with flluids- I dont have money for rebuilding trans.

Until my tranny gets super hot ( which is almost 1hr of fun driving) my gear change 1-2 is very crunchy/notchy, etc when it is cold.
After 1hour of 3-4K rpm driving, my 1-2 gears are smooth as new.
I am currently running Pennzoil Synchromesh fluid in my O2M VW/Audi 6spd Manual. 75W GL-4 is factory fluid. 73K mile.

I did money shifted once. Mistakely pushed my gear knob in 1st gear until it made grinding sound with clutch pushed in, at 55MPH! Didn't went thru, it was going in and grinding and I pushed knob back asap. All clutch in so no engine damage.

After changing to Pennzoil Synchromesh fluid it doesn't grind at all but just notchy and lil crunchy. 1-2 gear goes in with vibrating feedback from knob when it is cold.

The fluid I had 1-2 gear change high rpm grinding was Febi 21819 GL-4, for VW manual trans. 40.8 cSt at 40c (104F) and 6.7 cSt at 100c (212F).
Btw,

I found this:
BG Synchroshift II 37.85cSt at 40c(104F) and 7.11 cSt at 100c(212F) and GL-4 applicable [not sure it is full syn, but they have Mercedes approval (Mercedes Benz PN 900260315)]
Pennzoil Synchromesh 41.6 cSt at 40c (104F) and 9.08 cSt at 100c(212F) GL-4? (heard it is dino oil)
I heard MTL MT-80 is thickest among this , 50.8 cSt at 40c (104F) and 10.4 cSt at 100c (212F) and these are full syn.

Does viscosity matters a lot for smooth gear? or the friction materials matter?
My Febi fluid was 40.8/6.7, which is thinner than synchromesh fluid but synchro feels better with synchromesh.

Should I try MTL MT-80 or BG Synchroshift II?

Clutch is already bleeded and my car uses hyduralic clutch system if that matters, but I am sure my clutch life is almost done because most of Audi TT 8N owners replace their clutch around 72~78k mi.

+ VW official fluid for my car is

VW G052527A2- which is 75W80 or ​

VW G070726A2​

I think.​

 

[CleverUserName]

It’s very popular on the 02M and 02Q VW TDIs to do a 50/50 fluid change with blended Redline MT/LV and Superlight shockproof on higher mileage transmissions. I’ve done it on a couple cars and it was better than before.

Gear Oil, Red Line MT-LV (1qt) – Cascade German Parts

www.cascadegerman.com

Gear Oil, Red Line Superlight Shockproof 1qt – Cascade German Parts

www.cascadegerman.com

 

[TT'ed]

It’s very popular on the 02M and 02Q VW TDIs to do a 50/50 fluid change with blended Redline MT/LV and Superlight shockproof on higher mileage transmissions. I’ve done it on a couple cars and it was better than before.

Gear Oil, Red Line MT-LV (1qt) – Cascade German Parts

www.cascadegerman.com

Gear Oil, Red Line Superlight Shockproof 1qt – Cascade German Parts

www.cascadegerman.com

Thanks a lot. Considering my notchy transmission with pennzoil synchromesh, can MTL MT-90 make it worse?it is thicker fluid

 

[MolaKule]

Hey everyone, I have some questions for people who prays with flluids- I dont have money for rebuilding trans.

Until my tranny gets super hot ( which is almost 1hr of fun driving) my gear change 1-2 is very crunchy/notchy, etc when it is cold.
After 1hour of 3-4K rpm driving, my 1-2 gears are smooth as new.
I am currently running Pennzoil Synchromesh fluid in my O2M VW/Audi 6spd Manual. 75W GL-4 is factory fluid. 73K mile.

I did money shifted once. Mistakely pushed my gear knob in 1st gear until it made grinding sound with clutch pushed in, at 55MPH! Didn't went thru, it was going in and grinding and I pushed knob back asap. All clutch in so no engine damage.

After changing to Pennzoil Synchromesh fluid it doesn't grind at all but just notchy and lil crunchy. 1-2 gear goes in with vibrating feedback from knob when it is cold.

The fluid I had 1-2 gear change high rpm grinding was Febi 21819 GL-4, for VW manual trans. 40.8 cSt at 40c (104F) and 6.7 cSt at 100c (212F).
Btw,

I found this:
BG Synchroshift II 37.85cSt at 40c(104F) and 7.11 cSt at 100c(212F) and GL-4 applicable [not sure it is full syn, but they have Mercedes approval (Mercedes Benz PN 900260315)]
Pennzoil Synchromesh 41.6 cSt at 40c (104F) and 9.08 cSt at 100c(212F) GL-4? (heard it is dino oil)
I heard MTL MT-80 is thickest among this , 50.8 cSt at 40c (104F) and 10.4 cSt at 100c (212F) and these are full syn.

Does viscosity matters a lot for smooth gear? or the friction materials matter?
My Febi fluid was 40.8/6.7, which is thinner than synchromesh fluid but synchro feels better with synchromesh.

Should I try MTL MT-80 or BG Synchroshift II?

Clutch is already bleeded and my car uses hyduralic clutch system if that matters, but I am sure my clutch life is almost done because most of Audi TT 8N owners replace their clutch around 72~78k mi.

+ VW official fluid for my car is

VW G052527A2- which is 75W80 or ​

VW G070726A2​

I think.​

Redline MTL-75W80 would be the best viscosity match.

MTL® 75W80 GL-4 Gear Oil

Popular for BMW (before 1993), Honda and Acura, Ford Focus, late-model Mini Cooper, Dodge & Jeep NV 1500, 3500, and 5600

www.redlineoil.com

Do not add anything else.

 

[TT'ed]

Redline MTL-75W80 would be the best viscosity match.

MTL® 75W80 GL-4 Gear Oil

Popular for BMW (before 1993), Honda and Acura, Ford Focus, late-model Mini Cooper, Dodge & Jeep NV 1500, 3500, and 5600

www.redlineoil.com

Do not add anything else.

Thank you. going to give it a shot!

 

[benjy]

my 2001 TT 6 spd manual loves Redline MT90 in PA, but its a garage queen in the winter unless my truck is ailing!!

 

[930.engineering]

.
Sorry. I'm late.

Until my tranny gets super hot ( which is almost 1hr of fun driving) my gear change 1-2 is very crunchy/notchy, etc when it is cold.

"1-2 somewhat notchy" is normal for a VW transmission. It's a feature . . .

I did money shifted once. Mistakely pushed my gear knob in 1st gear until it made grinding sound with clutch pushed in, at 55MPH! Didn't went thru, it was going in and grinding and I pushed knob back asap.

(question: short shifter?)

After changing to Pennzoil Synchromesh fluid it doesn't grind at all but just notchy and lil crunchy. 1-2 gear goes in with vibrating feedback from knob when it is cold.

2nd synchronizer. Somewhat normal, but a thinner MTF might help a bit.

The fluid I had 1-2 gear change high rpm grinding was Febi 21819 GL-4, for VW manual trans. 40.8 cSt at 40c (104F) and 6.7 cSt at 100c (212F).

VW G 052 527 MSDS 2020:

KV40 27,6 mm²/s
KV100 6,1 mm²/s
0,851
PP -51°C
FP 208°C

Its predecessor VW G 052 171 might be slightly different but most probably similar since
VW used to use them both in the same transmission (02Q), of course depending on year.

BG Synchroshift II 37.85cSt at 40c(104F) and 7.11 cSt at 100c(212F) and GL-4 applicable [not sure it is full syn, but they have Mercedes approval (Mercedes Benz PN 900260315)]
Pennzoil Synchromesh 41.6 cSt at 40c (104F) and 9.08 cSt at 100c(212F) GL-4? (heard it is dino oil)
I heard MTL MT-80 is thickest among this , 50.8 cSt at 40c (104F) and 10.4 cSt at 100c (212F) and these are full syn.

I'd bet RL MT-80 is a great MTF, but I doubt it helps when cold.

Does viscosity matters a lot for smooth gear? or the friction materials matter?

Both highly important.

My Febi fluid was 40.8/6.7, which is thinner than synchromesh fluid but synchro feels better with synchromesh.

Apparently more appropriate friction modifiers as the Febi's.

Should I try MTL MT-80 or BG Synchroshift II?

I'd try Castrol Syntrans V-FE 75W-80 = Castrol Transmax Manual V 75W-80 (KV40 40 mm²/s,
KV100 8,1 mm²/s, PP <-60°C, FP 220°C, mainly PAO) or just VW G 052 527 (but above 50$/l
and you need 3 bottles for 2,3 l . . . ).
Castrol sell excellent MTFs with no less than top-quality ingredients. Castrol explicitly suggest
Syntrans V-FE/Transmax Manual V as a replacement for VW G 052 527 and G 052 171. I ran it
in my own 02Q for a couple of years and while marginally differently feeling to my hand, but
definitely no worse than with G 052 527 (before and after). I run VW's own again just because
I still had it on the shelf and it's way too costly not to use it.

Clutch is already bleeded and my car uses hyduralic clutch system if that matters,

Yes, it matters.

but I am sure my clutch life is almost done because most of Audi TT 8N owners replace their clutch around 72~78k mi.

A "sticking" clutch disc would distinctly affect shifting (and impair your sychronizers as well).

+ VW official fluid for my car is

VW G052527A2- which is 75W80 or ​

VW G070726A2​

I think.​

G 052 527 ist a 75W* GL-4 MTF. That suffix A2 means simply one-liter bottle.
G 052 527 replaced G 052 171 in 2012 (September).
The MQ350/02Q replaced its predecessor MQ350/02M between 2003
and 2006 (depending on model and market) still with the same G 052 171
of course.
So your 02M definitely came with VW G 052 171 and I see no impediment
to run G 052 527 on your 02M as well as with the same proven replacements.

*or even 70W, but the MSDS doesn't disclose sufficient data for such claim

my 2001 TT 6 spd manual loves Redline MT90 in PA, but its a garage queen in the winter unless my truck is ailing!!

MT90 is certainly no good idea for this particular transmission at freezing temps.
Probably a reasonable or even a great choice for warmer climates and different
use cases such as on track.

.