1995 VW Van possible synchro issue thoughts?

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Hi guys,

A good friend of mine has a mid nintees VW Van with the Audi 5 cyl and a manual transmission.
The van runs great, and the transmission shifts fine usually, although third gear has been giving him the odd issue.
Under a normal upshift into third it shifts fine....with a very slight crunch if he's hustling it, the issue is on the downshift.
When downshifting from 4th it will sometimes balk, or make a nasty crunch sound as if it was a bad synchro.

We both feel like a synchro issue is usually on the upshift.

Does anyone have this problem, or any thoughts?

Thanks,

Ryan
 
Try a new gear oil. The synchro is probably worn out. Not worth fixing unless you can do it yourself and you really want to fix it. $$$$ to have a mechanic do it.
 
He just changed the oil, from probably original fluid.

Are there any gl4 fluids that you guys would recommend?

Would royal purple synchromax be the correct weight?
 
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Have him check all the shifter bushings.

Probably a different setup, but on my aunt's 70' Beetle it shifted pretty bad when she first bought it. The shifter bushings were toast, I replaced them and it's pretty darn good now.
 
Originally Posted by ryan2022
Are there any gl4 fluids that you guys would recommend?
Red Line MT-90 75W90 GL-4 Full Synthetic Gear Oil.
Downshifts are where bad/worn syncros really show themselves, this is where you can really hear the syncros spinning up the gearset.
 
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VW owners swear by Redline MT90. Do not use the Royal Purple as it's designed for manual transmissions that take automatic transmission fluid. It's a light viscosity.

However I don't think there's a magical fix to your friends transmission. I had the same issue in my old S10, 3rd gear syncro was pooched. I had to double clutch or rev match it most days, this will likely be what your friend will have to do unless he wants to go through an expensive rebuild.
 
Molakule has a good treatise here on BITOG re MTL's; cannot put my hand on it just now. In it he gives a breakdown of various viscosity ranges. U should find out what the vw owners's manual recommends and go from there... generally lighter MTL within the same overall SAE viscosity range will give better synchro action at the expense of slightly lower gearface + rolling element bearing wear protection. But friction modifiers are also at play with synchro feel. Redline is one of the best out there for shift feel improvements - but a certain contingent of folk have seen evidence of additive drop-out / sludge formation - and the net fluid left giving no wear protection - with some Redline products. Hence they have seen heightened wear ...®.
 
Originally Posted by Delta
VW owners swear by Redline MT90. Do not use the Royal Purple as it's designed for manual transmissions that take automatic transmission fluid. It's a light viscosity.

However I don't think there's a magical fix to your friends transmission. I had the same issue in my old S10, 3rd gear syncro was pooched. I had to double clutch or rev match it most days, this will likely be what your friend will have to do unless he wants to go through an expensive rebuild.


Unless they operate in cold weather then its the worst fluid in the world it just plain sucks. I run Pentosin MTF2 after horrible cold shifting with that Redline, it was money down the drain. IIRC it has been discontinued by Pentosin but RAVENOL MTF-2 75w80 works as well.
With MTF2 shifting in winter is the same as summer, no noise or weirdness even in 100f weather.
 
Originally Posted by Nick1994
Have him check all the shifter bushings.

Probably a different setup, but on my aunt's 70' Beetle it shifted pretty bad when she first bought it. The shifter bushings were toast, I replaced them and it's pretty darn good now.

The OP's friend has the Eurovan, the T4 which is a transverse FWD layout that's much simpler than the T1-T3 that's literally a little T-drive bus. It should be a cable-shift like the A2-A3 Jetta/Golf of that era.

Try a GL-4 manual transmission oil first before looking at a rebuild.
 
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