1985 gtv alfetta... Hi all need advice on my reverse gear, pops out of gear when there is the slightest amount of acceleration ? it goes into gear fine but pops out with a gringing noise followed by bang ? the rest of the gears are fine
Sagging engine mounts? Bad trans rear mount? Check to be sure your fan is parallel to the radiator. When the mounts sag, it can set up the shift lever inside the boot to push itself out of gear when power is applied. Has it ever had new mounts? 20 + year old mounts are about done. Hope this helps!
Best, Gordon Raymond
Even with new mounts all 'round, mine still ocassionally does that too.
I've gotten into the habit of fully selecting 4th before making the run to reverse, and if it does pop out anyway, repeate the 4th to reverse pattern again. (I've got it in my head that it helped sync things a bit better than just putting it straight in)
It seems to have cut down on the number of jump out occurences to the point where the only time it does it now is if there's a crowd to watch, listen, and heckle.
Sounds like a sagy rear trans mount to me. When the mount sags the shifter boot gets bunched up, not allowing the shifter to put the trans fully in reverse. Might try pulling up on the boot as you shift into rev and see if that helps.
As a temp fix on mine I stuffed some short pieces "push on" hydraulic hose between the bottom of the trans and the crossmember. That brought the trans back into position. Worked great until I got around to changing the mount.
I don't have a definative reason for this, but if it something that has afflicted the odd 105 and 116 cars for years. The fork can wear significantly at the contact patch that locates the gear in position. I would build up this point with braze and reshape the fork to suit. I have had lots of each type and most fix it, some don't. I never in years of working on both types of trannies (no, not that type of tranny!) worked ot a reason that some cars develop this fault and some don't. Could be backing up steep hills regularly. I don't think it is anything to do with the mounts or linkages (116) initially, but may be all to do with gears or useage.
If I was overhauling a transmission and the owner mentioned the problem, I would look for a better gear set in my pile of spares, but usually I would only make the effort this for my own cars. I would always check for wear on the fork.
You see, as the reverse gears are straight cut, sliding mesh unlike the forward gears that are constant mesh and rely on the syncro sleeve for engagement (no axial thrust on the selector fork once in gear). The reverse gear relies on no axial thrust while they are moving. The only thing that keeps the gear in mesh is the dedent ball on the selector shaft and the fork to hold the gear in the right spot. Once it starts happening, you if you don't fix it it it will probably get worse. My advice is, hold the lever in reverse when backing until you have the trans pulled down.
It is worth checking that the lever mount is located correctly. Too far either way can prevent the lever getting full engagement either end of the shift spectrum. An 85 model should be an Isostatic car, but I don't think that makes any real difference.
The transaxle reverse is unsynchronized and straight cut. Popping out of reverse means the reverse idler teeth can not hold between the reverse gears on the layshaft and mainshaft. This usually happens when someone shifts into reverse without slowing the shafts down - done by shifting into a forward gear and quickly shifting into reverse. You will need to replace all three gears to fix the problem.