I have already tried to search, but most answers were regarding the Getrag. I have a '99 Z with the Isuzu 5-speed. It is my daily driver and stays outside in the winter. I am considering changing the oil in the tranny to a synthetic hoping to get smoother shifting when cold. It now has 125k miles and the shifting is getting a bit notchy in the mornings and it is still in the 40s still. Really concerned when it drops below freezing in the coming weeks.

Any recommendations on which fluids to try? Personal experiences from those that live in areas similar to KC with the broad range of weather we have would be helpful. We go from 105F in the summer to 0F in the winter, so it has to put up with both extremes.

Syncromesh... the ONLY option... get it at the dealership.

Well I am assuming that is what is in it, so that wouldn't help much.

I've got synchromesh in mine that was changed less the 10k ago, and my tranny feels like molasses when it's cold. Hopefully someone has a good cold climate alternative.

My uncle is a parts manager at a GM dealership in LA and he has always told me to run a good quality 5w30 full synthetic. I have ran that in probably 4 transmissions through the years of buying and selling j-bodys. I have never had a problem. Even ran it on my sedan when it had the turbo on it for 20k+ miles and never had any problems.. My .02 cents...

you could also try syncromax from royal purple... i would stay away from oil as it doesnt have friction modifiers needed for the syncros... without those bye bye syncros

Thanks Wrench Monkey, just did a quick google on it, and syncromax looks like some good stuff. I also agree with you on the 5w 30

I use royal purple Synchromax in my NVG...

-Chris-



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