I have this problem with the transmission where it slips out of 5th if I let off of the gas quickly:ermm:. Had this problem on a '69 VW also, but never fixed it. What causes this, and what's the fix? Thanks.

Usually, the fix is rebuilding the tranny, unless you have a clutch adjustment issue. But if it was clutch, you'd probably have issues in all of the gears. I had the same problem with the 5-speed I installed, then removed, last year. Gonna have it rebuilt this coming Winter.

Could be damaged shift fork (bent or worn) could also be worn gear. A knowlegdable guy at a tranny shop should recognize symptoms and offer solutions. Previous experience with 4 speed chev was bent shift fork.

Simple answer: Time for a rebuild most likely. This happened to my 78 a few years ago.

I have had this happen on last gear -3rd,4th or 5th on several used/abused cars in the past. I was always told it was the syncro - dont know for sure.

My '90 Nissan pickup was loosing teeth on 1st gear , as it got worse I found it harder to get it into 1st gear and it would pop out of gear when I lifted the gas pedal.

Shifting forks bent or worn out makes sense to me. But tranny innards are mysterious things to me!

Worn syncro, loosened mainshaft nut (allows excessive endfloat of gear) or weakened spring/check ball holding shift rod in place in 5th gear. I present these in order of probability. Shift forks are cast aluminum in these transmissions. While there is wear at the shift fork to syncro housing it is usually minimal unless you hold the shifter tightly in the gate while driving which loads the fork unnecessarily.

Edited February 26, 201015 yr by ezzzzzzz

The most common cause is the countershaft bearing in the trans is worn out thus allowing the gears to separate during deceleration. So since you need to open the trans to replace the bearing, it would be prudent to overhaul the whole transmission.

Curtis, front or rear bearing? I'm curious how many of these transmissions you've rebuilt. I've never seen a transmission with the wear you suggest that didn't howl like a banshee. Very low oil level or a catastrophic failure would be the cause. Since he has to go into the box it does make sense to rebuild it.

Curtis, front or rear bearing? I'm curious how many of these transmissions you've rebuilt. I've never seen a transmission with the wear you suggest that didn't howl like a banshee. Very low oil level or a catastrophic failure would be the cause. Since he has to go into the box it does make sense to rebuild it.

I've rebuilt one transmission and had two more rebuilt for me. The bearing closest to the top gear develops slop and the shifter pops out of gear during deceleration. The howl you talk about happens much later and typically you have to hold the transmission in gear with your hand at that late stage.

Mine used to pop out of fifth when under power. If I just cruised in fifth no worries. Took the box in to a good shop and it turned out to be worn dog teeth on the fifth syncro. Had a box of other gearbox bits out of the parts car so it was an easy fix. So just take it in and get it looked at my a pro.

Mine used to pop out of fifth when under power. If I just cruised in fifth no worries. Took the box in to a good shop and it turned out to be worn dog teeth on the fifth syncro. Had a box of other gearbox bits out of the parts car so it was an easy fix. So just take it in and get it looked at my a pro.

Took possession of the '78 Z today:classic:. Drove it about 40 miles today and it only slipped out twice. I do not have to hold it there by hand. Cruising it was fine. I'll replace fluids all the way around including the differential and see what I've got. BTW, it runs much better now with new plugs and wires, new distributor cap & rotor, and new air regulator. Now I move to new struts (and maybe springs), then weatherstripping and vinyl work. Dash, etc looks great.