Yoko-Chan

Hello friends,
I just finished putting my rebuilt transmission back in and changed my clutch and it was fine for maybe 70 miles but now it’s kicking me out of 1st gear. At first I thought I wasn’t pushing the shifter all the way but I have confirmed that’s not the issue. If I start the car in 2nd she drives normally. Please help!

thanks for your time,
- Will

lucky131969

Did you have the neutral lock pin engaged when you reinstalled the shifter per the service manual?

Yoko-Chan

I did notice a small roll pin on the floor of the garage after I put the transmission back in, could that pin have backed out?

lucky131969

So I take that as a no on the service manual...I will PM you the shifter install which shows the neutral lock pin.

Did you rebuild the transmission yourself?

Yoko-Chan

my uncle and I rebuilt it, we had the tremec manual but it didn’t mention it. Thanks for sending me the vid!

lucky131969

So here's the thing, there is one roll pin that I know of in the MM6, and it's for the shift offset lever. Hopefully what you found on the floor is not the same one depicted below.

robmiz

If you missing that roll pin you’ll know it. There would no resistance to the shifter. My best guess and you’re going hate it… you need to look at that synchro, sound like one of keys is pushed to 1st gear side and staying there. Which won’t let synchro sleeve fully engage first gear and usually pops back out into neutral… and let you still engage 2nd gear with 2 other keys are still in place. Which means the keeper spring was installed incorrectly with keys… yeah it sucks… tearing it down again. You might be able to it get in place without a complete tear down…. But this is my best guess… good luck. I would call RPM and ask for their advice before anything.

hungryhippo

What shifter? If it's aftermarket, make sure its centered properly

TMODcustoms

When it comes to issues shifting you always want to consider the alignment of the shifter & box. However, if you can get into all the gears that means your alignment is good to go, that's it, if you have RED Loctite on the linkage bolt you're done. The only time you'll have problems with only one gear is if the shifter (right to left alignment) is off (if this were the case you'll get first but not reverse or the opposite). Or (this is most common issue and the reason for RED Loctite) the bolt on the linkage is too loose or has loosened up, which allows the shaft from the box to slip inside the collar that connects it to the linkage. It will allow the shaft to slip just a little bit, at the very end of the travel/rotation. When this happens you are moving the stick all the way to one side or the other of it's travel. It feels like you're where you want to be in the gear but the slipping shaft allows the linkage to rotate just a little bit less than it should be rotating which ends up being just shy of getting into the gear.

Lots of people think you can make the shifter/box alignment "better" by fiddling with it but that is not the case.
In this case, since first is an issue, the box could be too far forward to allow enough engagement into first but if that is NOT the case for third and fifth as well then the box alignment is NOT the issue. If the box is too far forward or backward you will have problems getting into all the front gears; 1,3 & 5 or all of the aft gears; 2,4 & 6.

This is not going to solve your problem, and I'm sure your not looking for extra things to do but if you have to pull the gearbox consider sending in your linkage to be upgraded. I replace the factory pinned ends with ends that use bearings instead. This eliminates a ton of the slop and vibration that is transferred from the rest of the car into the shifter and into the cabin. It doesn't matter what shifter your running it will feel better with the linkage upgrade and it will stay that way forever instead of getting sloppier everyday. If your running a shifter that makes use of the factory box you can send that in to be upgraded as well, these two upgrades, will make a stock shifter or any aftermarket shifter feel significantly smoother, less sloppy and reduce all or most of the vibration / rattle these cars are known for.