syncro in 3rd gear not working

[jchealey]

I have a A+ transmission in a MK1/2.  shifting up to third is perfect.  Shifting down is a crunch.  Double clutch does not help.  I had bought a transmission rebuild from Guessworks and installed it, so the parts are new.  I am looking for ideas on the problem. 

thanks

Jerry

[MiniDave]

Sounds like either a synchro issue or a worn operating sleeve, I think the trans will have to come back apart to fix it.....have you contacted them about it to see what they say?

[jchealey]

I would have to contact my wife and I since we did the work.  And we don't know why there is an issue.  Never had a problem with a transmission before, but this is the first mini I have worked on. 
I was pretty sure I would have to take it apart again.   

Jerry

[MiniDave]

You bought a complete transmission from Guessworks and installed it?

[jchealey]

No,  we bought a rebuild kit for the transmission.  We installed all the parts.   

Jerry

[MiniDave]

OK, now we may be getting somewhere......did the kit include new operating sleeves?

Reason I ask is I overhauled the transmission in my Dino, and I could not get first gear to work. when I took it apart again I realized the op sleeve was damaged, but since it only was used on first gear, only one side was- I turned it around and everything worked perfectly.

The Mini trans is not made the same way, but a damaged op sleeve will keep it from shifting, especially down.

A few other things to check, (rod change gearbox, right?) is the stud that goes up thru the bottom of the case that the shift forks pivot on good and tight?

Everything else will require disassembly to diagnose......

What part of the world are you in?

[jchealey]

Sacramento,   I will check the bolt holding the shift mechanism.  Might as well look for the long shot. 

Jerry

[MiniDave]

Chances are that isn't it, but if it's loose....

[jchealey]

http://www.guess-works.com/Shop/Parts/display.htm?id=112

This is what came in the kit from Guess-works.  I see no mention of operations sleeves and did not see it on Mini Mania web site.  So give me a hint, is there another name for operating sleeve?

[MiniDave]

There may be a different name for them in England, but I didn't see anything in that list that I would call an op sleeve.

[MPlayle]

Is it when downshifting from 3rd to 2nd that you are having problems?  How is the condition of the bobbins holding the rod shifter to the tunnel?  If they are allowing the shift housing to rock sideways a bit, the rod may not be rotating quite enough to change shift forks properly.

[jchealey]

4th to third is the problem.  The bobbins were replaced in the rod shifter housing, the housing is secure.  3rd to 2 is good, as is 2 to 1st. 

[towjoe]

JC
John Guess is very helpful. Try emailing him or phone call might help.
John is excellent on customer service.
Regards
Towjoe   77.gif

[jeff10049]

It's gotta come back out did you check the new synchro's for height on the cone(the distance between the synchro and gear), and roundness not uncommon to get a bad one.

Did you save the old ones maybe using the best old one in this location since they worked would be good. You can get more life out of old ones by taking some meat off the back of them to get the height/distance back in spec.

As the synchro wears it will sit lower on the cone until it hits the gear and quits working as it can no longer get friction on the cone to match the gear speed. I have seen new ones sit right down on the gear they were made too big.

Jeff

[jeff10049]

You know I just realized you said it up shifts fine so i'm wondering about the indexing of the ring it could be made wrong maybe its lined up and not blocking on the downshift side sounds like the ring is shit at any rate.

Jeff

[jchealey]

No matter what, it has to come back out.  Driving in the hills is no fun when you can't get back into 3rd!  I think I will change it back to the 3.4 final drive also. 

Jerry

[MiniDave]

What final drive do you have now?

If you do mostly town driving the lower ratio is fine, but I do a lot of long hiway drives - so I run the 2:76 gears. I was concerned that it would be doggy around the hills of southeastern Mo and northwestern Arkansas where we do most of our runs but so far I'm pretty happy with it, and on the highway it's only turning 3500 @ 75 mph, so I can easily run with highway traffic without the engine screaming......

[jchealey]

I have a 2.9 final drive.  I assumed that with my engine enhancements that I would have enough power for the 2.9.  I estimate my HP at somewhere around 90+.   Like you, it works fine around town, but limited acceleration on hills in both 3 and 4th.  It just screams starting out in 1st , 2nd, and 3rd.  The lack of torque in 3rd might be my inability to shift down from 4th in a timely manner.  If I do a slow count of 3 and make sure the car is at idle, it will then go down to 3rd, but by then you have lost momentum. 
My freeway tach is 3800 at about 68mph. 

It is very fun to drive, but that 3rd is a problem. 

Jerry