[Bocephus357]

Recently when shifting into 5th when the tranny is still cold it grinds while I am trying to shift into 5th. It only does it when it is cold outside, and before the tranny gets warmed up. Also it has only done it while shifting into 5th. It has happened several times over the past few weeks. The first few times I was shifting from 3rd to 5th, and recently it has been when I have been shifting from 4th to 5th. The first time it happend I chalked it up to driver error. By the time I am about 3 or 4 miles from my house, the tranny seems to be warmed up and I have no problems.

I was talking about it to a friend of mine, and his first thought was the syncro (not sure if spelled right) but he said it would happen going into 2nd and 3rd before 5th. I have never had problems going into any other gear.

Anybody have an idea of what it could be? Is the tranny just too cold, or do I have clutch or tranny problems? I have about 7600 miles on my Mustang so far so I wouldn't think it would be the clutch.

Any ideas guys?

[Saleen 281]

Try the following: When exiting 4th gear to go to 5th shift to neutral and let the clutch out. Depress the clutch again; blip the throttle to 2k and it should slide like buttah into 5th. The Tremec is usually too beast to give up this early in the game. If it does grind after you follow the directions above then it's most likely a synchro. (No matter really since it's not a gear, but get thee to a warranty to have it fixed.) 2nd, 3rd and 5th (on the 3650) are on the same gearset, so yeah, it would grind, give the synchro an extra second to spin the gear to the correct speed when going from 2nd or 3rd to 5th. 1st and Rev are on their own gearset and 4th is an anomaly. I’ve rebuilt a 3650 and 4th is a “synchro gear, gear and synchro together” that probably doesn’t make sense, but that’s how it is and that’s how it works.

Besides all that jazz, jack up the right side of your car, get to the fill bolt of the tranny under the car, un-ratchet it and listen to all the pressure PSSSSSSSSSSSSSSS come out. That could also be the prob, or the fact that Ford uses ATF in their Manual Trannys!?!? Hey, it works, so don’t knock it...right, or can I mock it?


That leads to a third option, squirt some transmission slick "stuff" (goes by manny names) into the tranny and that should all but 99% fix your prob! Whew.

[Bocephus357]

Thanks. I'll try shifting to neutral then into 5th and see if that helps. I figured since I have just under 8,000 miles on my car that hopefully nothing was wrong.
Maybe over the weekend I'll jack it up and open the fill bolt.

Also if the tranny fluid was low, would it cause this or not?

[Saleen 281]

There really is no way for the fluid to be low unless there is a leak. I found that mine was overfilled and let it drain out until it came up to right underneath the check level bolt on the side - the one used to let out the pressure. You drain by using the bottom bolt in small increments because it's a hell of a lot easier not having to refill it back up to the correct level.

A lot of people have come across the same type of problems you are encountering so you're not alone. I have heard of people refilling the trannys with royal purple, adding slick shifting additives and when I ask the dealership techs not one person knows why ATF fluid is in the manuals, but its worked for years so they stick with it.

[stlwagon]

Doubtful if it's a syncro if it only does this when cold.

[Bocephus357]

Do you guys think switching to Royal Purple would help any?

I tried what you sugested Saleen 281, by shifting from 4th to N then rev to 2K then to 5th and that has worked. I have done that until the tranny gets warmed up then shifted normal and I haven't had any problems.

It just buggs me why I can't shift from 4th to 5th normally when its cold.

[travelers]

If you go from 3rd to 5th you need to let the RPMs drop way down and don't force the trans. RP syncro max is what I'm using works good.

[Bocephus357]

The first time or two I was going 3rd to 5th, but I haven't done that in a while when the tranny is cold. I have just been going from 4th to 5th.

How many miles do you guys recomend replacing tranny and rear end fluid?

[travelers]

I think it was around 18K that I did mine. I think the manual tells when it should be changed.

[sqidd]

It is simply a byproduct of cold trans fluid. I won’t bother explaining why, no one listens anyway. You can do one of two three things. Wait a lot longer between 4 and 5th gear when shifting, put lower viscosity oil in (not smart, it will get warm), let it sit outside and warm up forever before you drive it.