Jump to content

Mojos 72z

Tranny swap problem

Recommended Posts

Have a 72 and recently swapped a 5 speed in for my 4 speed.  Car worked fine prior to the switch and the 5 speed was known to be fine.  Switch went well but find a problem with engaging gears.  5 speed smoothly shifts gears when the engine is off but with the engine started I cannot shift into gear.  There is a slight grinding of reverse gear when I try to put it into reverse.  If I shift into a forward gear with the car off then start it, I do get the car to jump meaning the car is in gear.  Using the same master and slave cylinder and last thing I have done is bled the fluid.  When pressing on the clutch pedal I get the clutch fork to move about a 1/4 inch.  Using same fork and bearing from the 4 speed.  Have a firm clutch peddle.   Have tried adjusting the slave cylinder pin.  Any thoughts?

Share this post


Link to post
Share on other sites

Clearly the clutch isn't releasing.
Did you refit exact same clutch kit?
I guess the 4 speed is f4w71b, but Which 5 speed?

1/4" movement of the fork doesn't sound right, I'd guess it needs a taller release bearing collar. But I might not be picturing it right in my head :)

Share this post


Link to post
Share on other sites

Talks us through what throw out bear and collar you used?  Did you check how the fork moved the collar before install the trans?

Share this post


Link to post
Share on other sites

Sounds like you might have a problem with the clutch release bearing collar. Did you use the one on the 4 speed or the one that came with the 5 speed? There are several different lengths available for the Zed transmissions and easy to mis-match to the wrong pressure plate. They match the pressure plate and not the transmission. A mistake a lot of us have made at one time or other.

You can check the position of the clutch fork. Should be about 110mm from the front of the transmission and the fork should travel about 16mm +/- 3mm.

So 110mm and with clutch pedal depressed 126mm.

If you have the wrong collar, the tranny will need to come out again.

 

post-25317-0-73657500-1426794302_thumb.jpg

post-25317-0-85403900-1426794320_thumb.jpg

Edited by EuroDat

Share this post


Link to post
Share on other sites

I'm using the same pressure plate, fork and collar that was used when the car had the 4 speed in it.  The collar and fork operated fine when installed in the 5 speed and I never gave it a thought that there could be various sized collars.  Sound like that may be the problem.  Thanks for the information and I will post on my progress.

1 hour ago, Zed Head said:

 

1 hour ago, Zed Head said:

 

  • Like 1

Share this post


Link to post
Share on other sites
7 minutes ago, Mojos 72z said:

I'm using the same pressure plate, fork and collar that was used when the car had the 4 speed in it.  The collar and fork operated fine when installed in the 5 speed and I never gave it a thought that there could be various sized collars. 

You suggested two different things in your post.  Said you used the 4 speed parts, but then said the 5 speed parts worked fine.  Not clear.

 

If you used all of the same parts that you had for the 4 speed it should work.  Could be something simple like the seal in the slave cylinder got damaged as the piston extended in the bore as it hung free.  Pretty common for seals to get damaged when they travel over unused cylinder bore corrosion.

Pop the rubber dust seal off of the slave cylinder and see if it has fluid inside.

Share this post


Link to post
Share on other sites

Well, what I meant to say was the parts used with the 4 speed (fork, collar and bearing) I transferred over to the 5 speed transmission not knowing that the collar may need to be changed to a taller collar. 

I have removed the rubber dust seal off and appears to be oil free. The slave is relatively cheap so I may go ahead and change that out before pulling out the collar.  

Share this post


Link to post
Share on other sites
7 minutes ago, Mojos 72z said:

Well, what I meant to say was the parts used with the 4 speed (fork, collar and bearing) I transferred over to the 5 speed transmission not knowing that the collar may need to be changed to a taller collar.

The collar matches the pressure plate, not the transmission.  That's the message we're trying to send.  The clutch fork pivot ball is in the exact same position on both transmissions, relative to the engine, flywheel, and pressure pate.  

You might just make sure that slave cylinder bleed screw is angled upward when bleeding.  Give it another bleed.

Sometimes people don't get the fork spring clips properly attached to the pivot ball and things get jammed up.  Maybe make sure that the fork is right.

Just offering suggestions.  There are no parts to suggest swapping to if you used all of the same parts from the 4 speed and did not change the pressure plate.

 

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, Mojos 72z said:

Well, what I meant to say was the parts used with the 4 speed (fork, collar and bearing) I transferred over to the 5 speed transmission not knowing that the collar may need to be changed to a taller collar. 

I have removed the rubber dust seal off and appears to be oil free. The slave is relatively cheap so I may go ahead and change that out before pulling out the collar.  

If you are using the same pressure plate and collar that came out of the 4 spead set up, than you should not have any problems with the height.

If the slave cylinder is not leaking and moves in and out freely, than there is no need to replace it.

Can you check the fork travel? It should be about 16mm, give or take a couple of mm. If it's less than 12mm, you will most likely have issues with disengaging and gears grinding like reverse.

You should be able to push the slave cylinder rod into the slave cylinder about 10mm. If you can not do that you need to do some adjustment checks. Two things can cause that. 1: The clutch fork is not seated on the pivot properly. 2: The master cylinder in not adjusted properly and not returning far enough to open the resivour port. It's not likely to be your master cylinder because it was ok before the tranny swap.

Other items that can cause your problems:

- Dry input shaft splines. The clutch disc can not slide along the shaft and away from the flywheel. This causes the disc to drag on the flywheel and feels like the clutch is not fully disengaging. Well one side of the disc is not disengaging. Did you try the clutch disc on the input shaft splines before fitting the transmission?

- A dry binding spigot bearing (bronze bush or sometimes a ball/needle bearing in the back of the crankshaft) will cause the same problems. It's rare and doesn't happen often.

Both these problems will need removing the transmission to fix. I would leave this as a last resort. Try all the easy stuff first.

  • Like 1

Share this post


Link to post
Share on other sites

And the winner is...EuroDat.  Replaced the clutch release bearing to a taller 5 speed one and it works.  Thanks for all the responses.

  • Like 1

Share this post


Link to post
Share on other sites
13 hours ago, Mojos 72z said:

And the winner is...EuroDat.  Replaced the clutch release bearing to a taller 5 speed one and it works.  Thanks for all the responses.

Double check that you have no slippage by trying to accelerate hard in a high gear from a low rpm. It is possible to end up in a situation where the clutch doesn't fully engage (ie get full pressure)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use. We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.