Slips out of first gear

[morganzoo]

Hello!

I am so glad I found this site! I just joined, and can't wait to get started on my project. I have a 1969 F100 302 column shift 3 speed with overdrive (T85N). It will not stay engaged in first gear, even while holding on to the shift lever. I can start out in second gear, (which was how my son drove it for a bit) and it shifts to third easily, but I am sure that is toasting my clutch. Does this sound like a linkage problem? Or should I think about rebuilding the transmission, or both.

Thanks in advance for your advice!

[Ranchero50]

Hard to say. Typically when it won't stay in gear, the dogs on the slidiers and gear have the reverse angle worn down and it's not a synchro or linkage problem. I'd undo the linkage at the tranny and make sure it's able to go completely into first gear. If it pops out when adjusted correctly look for parts.

It shouldn't terribly difficult to rebuild but you'll probably need first gear and the slider between 1st and 2nd along with a synchro kit and some bearings if they are pitted or worn excessively.

[tqwrench]

Ranchero gives good advice about undoing the linkage at the transmission and taking a short test drive to see if it pops out. If it does, then the likely culprit is first gear itself. The clutching teeth on the gear are trapezoid shaped, designed to engage the synchronizer sleeve and hold the synchronizer in place. When those teeth wear down, you'll have jump out on acceleration.

This same thing happened to my uncle's '51 F-1 pickup. It would jump out of 2nd gear, you'd really have to struggle with the shifter to keep it in under acceleration. The clutching teeth on 2nd gear were worn badly. A new gear resolved it.