I've been procrastinating on fixing this problem since I really don't need 5th gear much but everything points toward an improperly adjusted detent. It goes into gear nicely (no crunch!) but if I'm decelerating below 80mph it pops out of gear. I can hold it in gear but I'm planning on selling it in the near future.

I looked in the manual but the terminology is different or I'm overlooking it somewhere. So can it be adjusted or do I just replace the spring or both? A quick procedure or a place in the manual you could point me to would be great.

 

I don't think there is any adjusting of anything you can do... there's a ball and spring that rides in the indentations on the 5th gear shift rod... maybe your spring is worn.

 

Like Brian said, you can't adjust it, only check/replace it.

For the detente that holds the 5-R shift rod in 5th, check out J-16 of the FSM, Item 19. 19 points to the two ball-spring for the 1-2 and 3-4 shift rods, and the 5-R ball-spring is sort of unlabeled but forward of and in line with items 38 and 37.

You should be able to remove those parts without much trouble, and it might not require the tranny oil to be drained (I'm not sure, - depends if it sits below the oil check plug). With a magnetic pick-up it's fairly easy to remove, check, and reinstall. There should be pictures in my tranny writeup at www.davidgeesaman.com

Dave

 

If it's the detends in the shift rod you're talking about, they do ABSOLUTELY NOTHING to keep the car in gear. Their main function is to keep the tranny from slipping into gear when you want it to be in neutral. If it's the keys on the gear hub that you mean (some people call these detents also), they are there to just provide alignment for the gear selector.

On acceleration the gears twist themselves together (helical cut gears provide a little side force) to not pop out of gear. Usually that same twisting will keep them in gear on decel as well. It's possible that you have wear somewhere that is letting them flop around a little and not lock together. I doubt 5th gear is worn to that point unless you ran it dry or got **** in it (water through the vent maybe..) It could also be that 5th gear selector ring has been beaten up from missing/grinding too many 3rd gear shifts.

Either way, adding more oomph spring on to your shift rod detent is not going to keep it in gear. Sorry.

 

Thanks on the info..

The tranny was rebuilt, and then it started happening, with in a matter of days! It's a long story why i didn't take it back to the shop but lets just say "i had a bad experience" with them.

The things you mentioned: mishifts, running it dry, or wear should not be an issue. I had it rebuilt due to the typical 5th "crunch." That is gone after the rebuild but like I said it slips out only on decel and only in 5th.

From david geesaman's (GREAT WORK!!!!) page 12 on reassembly ::::: "each plug hole has a ball-spring inside engage a detente in the shift rod to give it that snappy feeling when it shifts and TO KEEP IT IN GEAR."

So...what's the deal? The detente holds shifter in or out of gear? Does anyone have any experience doing this with the tranny in the car? I'm assuming if you can access the detente spring through the plug holes you wouldn't even need to take off the lower pan/cover?

 

Man i thought i was going crazy for a few seconds.... J-18 is the page with the info, thanks for pointing out which part it is though. You've been a huge time saver...

 

I believe Dave (Newbern) in that the detentes aren't enough to hold the car in gear against the torque in the tranmission. I think the detentes are mostly there to be felt by the driver while operating the shifter. But the bottom one should be easy to check without removing much from the car. It's a good thing to start with for that reason alone.

However, the helical cuts shouldn't affect how the car stays in gear. There's not enough play in the gears for the axial thrust (caused by the helical shape) to move things around. If there was you'd probably have much bigger problems. Plus, under deceleration, the torque in the transmission is opposite acceleration (that jerking you feel if you let off the gas quickly without touching the clutch is the drivetrain slop as the torque switches direction and begins engine braking). The clutch hub, drive gear, and clutch are all straight cut engagement, and should not want to pop out of gear unless they are worn. The clutch keys, clutch key springs, and clutch hub sleeve and what would resist that force, but it wouldn't take much to overcome them.

Here's my theory: either they removed the 5th/Rev clutch hub and didn't reassemble it correctly, or the 5th/Rev clutch sleeve was worn and is not hopping out of gear since the new 5th synchro has altered things a bit. Or maybe the 5/R selector fork is bent and tending to push it out of gear.

The 5th/Rev synchro sleeve is available separately for about $40. I would first try to have them fix that tranny and install a new 5/R sleeve, as well as make damn certain the clutch keys, clutch hub, and clutch key springs are assembled properly. If they can't do it, it's not a tough job once the tranny is out of the car (basically it's the 5th gear synchro job again). I'm not sure if you can do all that in the car - I've heard Cam at Pettit does 5th synchro that way, but I've never tried it.

Oh, sorry about the bad page ref. J-18 also has a pic of the detente assembly though

Dave

 

I realized this as I was driving home.. I was thinking about something totally different. I was about brain dead by the end of today.

Just thinking aloud. Is it possible that it's adjusted just a little forward? If you can loosen it up and move it back a little it might help to engage 5th gear a little more. (Looking for options that don't require dropping the tranny again.)

 

I can't think of any way to adjust the important components without getting into the 5/r housing. And I don't know from experience if you can get to that point with it in the car. It seems it shoudl be possible, but I haven't tried it.

Dave

 

I'll give it a look this weekend, thanks for the help.