Fighting Transmission to get in Gear

[ksbeta]

Good evening,

When I pulled the 4spd from the '70 a year or so ago during the motor rebuild, it ran fine. I opted for a 5spd and so the 4spd sat covered in a corner of the garage, upright, but elevated to protect the spline.

When I re-installed the 4spd, I noticed it was difficult to get into gear. It felt as though there was something wrong with how the shifter itself was interacting with the box. I need to find the slot for the gear, and then apply an undo amount of force way down at the base of the shifter to get it to go in. Once it's in gear, it runs fine, but this same force is required for all forward gears, and reverse. I assumed I'd stored it improperly or otherwise damaged the box.

I sourced another 4spd; a low-mileage, rebuilt transmission from a '70 locally to swap in and alleviate the issues. But, the same amount of force is required with this new one.

Before I blame the transmission, does this sound indicative of an improperly installed shifter, or something similarly obvious?

Thanks in advance.

[LeonV]

Sounds like a hydraulic issue, possibly a leaky clutch master and/or slave cylinder. Also make sure your clutch pedal is adjusted correctly.

[EuroDat]

+1 on Leons post.

Does it grind into reverse? Isit worse when the engine/gearbox are cold? It could be the gear oil you're using is too thick. That should improve once the oil has reach normal operating temperature.

Chas

[ksbeta]

Leon, Chas, thanks much.

No grinding. Entirely possible I failed to readjust the slave cylinder (the distance) back from tohe 5spd to the 4spd. Will start looking there. Much appreciated.

[Sean240Z]

Bill,

When you swapped transmissions, did you change the clutch and pressure plate?

If no, when you installed the five-speed, did you reuse the clutch collar that came off the car? The correct answer is yes. The clutch collar has to match the clutch and pressure plate.

When I changed my clutch last year, I had to order a new clutch collar, as the new clutch I bought was a different thickness than the one I pulled off my Z.

[z boy mn]

I have the issue that EuroDat mentions...when it's cold (which is often in MN), it's really hard to get it into gear. I was thinking of changing over to synthetic to see if that would be better. Once the car warms up, it's fine.

[olzed]

I had an impossible to change gear scenario. I changed the pressure and clutch plate and the problem went away.

[Mark Maras]

IMO the answer is lighter wt. oil, The clutch adjustment should be checked, but I doubt that is the problem because the problem goes away when the oil heats up & thins out. I'm not knowledgable about oil but if the synthetics are thinner, I think you'll feel the difference. Mark

[Zed Head]

Re ksbeta's probem - The part about the force required at the base of the shifter and the fact that the problem followed the shifter is interesting.

If the problem is hydraulic or clutch related you should have grinding in reverse since it has no synchros. Reverse requires complete disengagement of the transmission from the engine, while the forward gears can use the synchros to do some work.

Have you checked the three plastic bushings of the shift lever? Especially the bottom one, maybe it's split and opening up or just not seating right in the pocket for the shifter mechanism. Seems like there's a shifter problem, which it looks like you suspect also.

[EuroDat]

A general rule.

Clutch related:

Grinds into reverse ALL the time.

Hard to get in gear and maybe slightly easier when transmission wams up and "thick" oil thins out.

See Leons post #2 and if you have a sreie I slave cylinder with the adjustable push rod, check the free play.

Oil related:

Grinds into reverse, but is a little easier when transmission is warm. (say after 30 minute drive depending on outside temperature.)

Gears are hard to engage when cold and normal or much easier when transmission warms up.

Look for oils like Redline MT-90 or Royal Purple Max Gear. GL-4 rated. I think a lot of the GL-5 oils can be used in our transmission, but they must be suitable for yellow metal.

Outside these the two above mention symptoms (clutch or oil) there are several other things that can cause dificult shifting:

If the shifter mechanism (striking rod guide or striking rod) in the housing is dry and binding, it will influence the force needed to change gear. The gears won't grind including reverse, but hard pressure is needed to engage them. It will also mean you will need more force to disengage gears. Pay attention when disengaging (pulling it out of gear) to neutral. If that is hard chances are thats it something binding in the selector causing your problems.

If the transmission has been standing for a long time on its (bellhousing) end the selector section can dry out and increase this phenomenon.

The palstic bushes can bind, but I havn't seen it yet mostly worn out with excessive play. The typical stick in the mud syndrome where the gear stick is very loose. Certainly doesn't mean it can't happen it dust gets in and it dries out. I have seen people use the brass or aluminium bushes and they can cause problems if the rubber boot is damaged and allows dust to enter. I prefer the plastic bushes, because the plastic doesn't "need" lubricating and they cost less than $10 and easy to replace.

It could be something with the rubber boot tunnel boot. Maybe the rubber is hard. Unlikly to get that hard that its causing this problem and you didn't have it before.

I doubt the detent springs or interlocks are the problem because its affecting all the gears.

Chas

Edited August 16, 2014 by EuroDat