Gl-5 or gl-4

[GARYT28221]

Hello Espada - I think you should use GL-4, even if have to order it. GL-5 has additives which can damage the brass synchronizers in a manual transmission.

I have been very pleased with Redline MTF. It's designed for manual transmissions, and contains friction modifiers than help the synchronizers get up to speed.

Best regards!

I drained old but working. GL4 IN 98 CABRIO. 200,000. PUT IN expensive REDLINE MT90 AND AT 0°F I HAD TO LET THE car IDLE FOR 15+MIN. TO GET IT TO SHIFT. !!? @100+ miles ..short trips..it got much better pushing each Synchromesh. I will retry with. Different GL4.. cheaper too. Hard to find.

 

[Number_35]

I drained old but working. GL4 IN 98 CABRIO. 200,000. PUT IN expensive REDLINE MT90 AND AT 0°F I HAD TO LET THE car IDLE FOR 15+MIN. TO GET IT TO SHIFT. !!? @100+ miles ..short trips..it got much better pushing each Synchromesh. I will retry with. Different GL4.. cheaper too. Hard to find.

Last change I bought Pennzoil Syngear GL-4 from NAPA.

Neither the Redline nor the Pennzoil have caused hard shifting in the 2009 Mazda5 I service, and we typically get winter temperatures colder than Minnesota.

 

[kschachn]

Hopefully Espada got this figured out nearly two years ago.

 

[4WD]

Hopefully Espada got this figured out nearly two years ago.

Yup - April 2021 - he left the building

 

[dumkid]

isn't newer gl5 less damaging to synchros than old gl5? i have a jug of gl5 in my garage that says it can be used in manual transmissions, and I was going to use it in a transfer case full of brass bushings