Is first gear synchronized? Should I be able to shift into first gear while going 5mph?

Yes, all modern transmissions on passenger vehicles are synchronized, especially the lower gears.

Brent

KAX, are you having trouble shifting into 1rst while moving? I've noticed the same thing..doesn't want to go into 1rst even around 5 or so mph. Anyone else experienced this problem?

I've noticed it as well, but I usually just wait until I am stopped to shift into 1st. If I'm going 5 mph and want to accelerate, I just leave it in 2nd - plenty of power.

Same here but I only have 800 miles on my '02 so it isn't broken in yet. First is especially ornery when the trans is cold. Cold or hot, I usually double-clutch before sticking it into first while moving. It will either get better with miles or I will just change to Redline synthetic after about 5k miles.

The Red Line synthetic MT90 is awesome. The red color makes it look like ATF but it works great. I put it in my yellow X at 12,000mi and am getting ready to change it again at 24,000mi. Very smooth shifts and less noise.

The reason I change the fluid way more often than the factory recommends is that I lost a manual tranny in my 90 Hardbody due to metal in the fluid. Since MT's have no filter I figure better safe than sorry.

Does anyone know if the Red Line voids the warranty? I recently had a chat with the local Nissan service manager and he pretty much said any mod does to a certain extent. Also, regarding shifting into 1rst. My biggest concern is the ability to downshift while in low range...example-going into steep/rough conditions from not so steep/rough while in second or third/low range.

Yeah, same here. Although I think it is a safety feature, since (as Mudflap stated) if you double clutch, there is no problem with the shift. It seems like the feature that prevents you from shifting directly into reverse without putting the transmission in neutral. That's only my guess though, I'm not sure if that is the reason why you have to double cltuch to shift into first while moving.

No syntetics will not void your warranty!!!! If your truck is past your "break-in" miles switch to synthetic oils! I know lots of happy people who run synthetic oil.

Just rev the engine a bit, it will sync up and slide right in.

Tranny Fluid Info

One of the most informative threads on XOC about which fluids to use in your transmission.

1st gear is somewhat harder to shift in to in all contemporary manual transmissions because the 1st gear synchro has the least mechanical advantage over the inertia of the clutch compared to the other gears. Its not a safety feature. If you care about the life of your tranny, double declutching is the right way to get into 1st gear if it doesn't want to go in easily while moving.

FWIW, trucks see this issue more than cars because the first gear ratio is often lower, and inertia seen by the synchro is proportional to the square of the ratio.

For dummies like me, here's a neat little article regarding synchro and double clutching.

http://integra.vtec.net/driving/dclutch.html