Synchronizers and gear oils
Synchronizers and gear oils
(OP)
I have a few questions about modern synchromesh designs that have been nagging me.
1) How much of a difference does a GL-4 vs. a GL-5 oil affect synchronization and synchro wear?
2) I see some mfrs using more double- and triple-cone synchros and others recommending friction modifiers to add to the gear oil. Is this to make the GL-5 oils synchronize like a GL-4?
Any other comments on this subject are appreciated.
Dave
1) How much of a difference does a GL-4 vs. a GL-5 oil affect synchronization and synchro wear?
2) I see some mfrs using more double- and triple-cone synchros and others recommending friction modifiers to add to the gear oil. Is this to make the GL-5 oils synchronize like a GL-4?
Any other comments on this subject are appreciated.
Dave





RE: Synchronizers and gear oils
Rather than speculate why not try it. You can always go back. Your main concern would very likely shift to operation.
RE: Synchronizers and gear oils
So for example, will using an extra-slick GL-5 wear out the synchros in a tranny designed for GL-4? Even if the GL-5 claims to be synchro-friendly?
Dave
RE: Synchronizers and gear oils
RE: Synchronizers and gear oils
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RE: Synchronizers and gear oils
The autos in question are imports. Most of these trannys appear to have been designed around GL-4 properties, but in the last 5-10 years the commonly available lubes are now GL-5 rated. The manufacturers have revised their literature to accept both GL-4 and GL-5 (rumored to be because of pressure from dealerships, who didn't want the hassle and cost of sourcing GL-4 anymore).
So the question remains, is this a semantic difference, or is there a significant difference esp. w.r.t. synchronizer wear and performance?
RE: Synchronizers and gear oils
Nick
I love materials science!
RE: Synchronizers and gear oils