Slipping $ shuddering reverse

[karmannghia60]

I lived with the issue for the last few years but now time to do something about it. When I put my '69 280SL in reverse, it will take about 10 seconds to engage and might shudder as well. If reversing up a slight hill, it will slip in/out. Took it to someone here who seem to know about them. He said best case scenario is a leaky piston. Worst case a worn band which will need the gearbox reco'd at about $5k,ouch. Another option is to get a 2nd hand gearbox but no guarantee that it will be any better than what I have so could be paying for labour to fit it more than once. What are the experts' opinions out there?
Thanks
Rafik
Melbourne, Australia

[Garry]

Hi Rafik,

Take your car to Joe Haslauer at Classique Motors South Melbourne who will probably give you a good opinion of what could be the problem and an estimate of cost.  He owns a few Pagodas him self and has done good work on my car provided you have plenty of time.  He can be a bit slow at times.

[ja17]

Hello Rafik,

It sounds like your reverse band adjustment has come loose.  If you are lucky, a quick adjustment will solve all your issues with reverse at little or no expense.

The 10mm adjuster bolt should be turned in until it is  snug then it should be turned out 1 3/4 turns. Next lock down the 22mm nut.

[karmannghia60]

Garry, Joe was the one who had a look at it last week and suggested the leaky piston or full rebuild anywhere between $3.5k & $5k

Joe, thanks for the tip, you wouldn't have a picture of where the 10mm adjuster is? I haven't touched a Pagoda transmission previously but I do have a Haynes manual
Thanks again

[karmannghia60]

Just found it in the Technical Manual section. Will check it today and see if it makes a difference

[ja17]

Hello Rafik,

Look at the picture in my previous post and you will see the adjuster and 22mm lock nut.

Good luck!

[Garry]

Hi Rafik, That's a worry, hope Joe A's suggestion is the problem and is the easy fix, I have generally found Classique to be good and reliable, I will be a bit more hesitant in recommending him..

[karmannghia60]

Hi Garry
Don't get me wrong, Joe certainly seem to know what he's talking about. I wasn't questioning his credibility. just the price of reconditioning the box scared me. I will try the adjustment first, might save myself $4k or $5k

[karmannghia60]

Ok, good & bad news
Bad news, the adjusting bolt was already near the end. Only had 1/2 turn left. Nevertheless, I tried what was suggested, all the way in then back 1 3/4 turn. No reverse at all. So I lifted the car again and tightened the bolt all the way and left it there. Now have reverse and no slipping or shuddering, so good news. But is tightening the bolt all the way in a problem?
Thanks

[glenn]

Sounds like you have a solution.  Had a reverse problem once.  The reverse piston(more like a disk with an o-ring) had split in two.  The MB replacement was about twice as thick.  It solved that problem.  Your's maybe split or cracked, also.

[ja17]

Hello,
Sounds like you may have a worn band.  Your soloution may be a good fix for the time being.  I would do a filter and fluid change to see what kind of debris you find in the pan. Otherwise, happy motoring!   

Good quality rebuilds in the USA can be had for a lot less (Sun Valley). Used units also are more common.

[karmannghia60]

Not so good news.Today on my way to work after driving for 20 minutes forward gears doing strange things kicking up and down then noticed some smoke coming from under the car, pulled over and got car towed home. Looks like tightening the bolt all the way in is causing other problems although reverse is working fine any further advise?

[ja17]

Hello,

Sounds like  you have reverse band too tight and staying partially engaged. Try loosening it one turn.

Also remove the pan and check for debris first chance.

[karmannghia60]

The car has been at the gearbox place for a week now without any progress. First thing they want to check is the piston but they can't remove it without finding a new gasket for it. Been looking everywhere in Australia and can't find a gasket for the piston. Still waiting for MB Australia to get a response from Germany. Anyone out there know where I can get a gasket from? Preferably in Australia but leads would be greatly appreciated
Thanks
rafik

[ja17]

Hello rafik,

I maight have a new  one. I need to know if you mean the piston ring, the piston, an o-ring, gasket  or what?  If you can point it out on a parts blow up it would help.  I also have lots of good used pistons bands etc. In case you need something else hard to find new. 

[karmannghia60]

Joe, you have a PM
Rafik (iiivvi@hotmail.com)

[Allenh]

I believe I have one, If I can still find it.  It is a paper version I bought before there was an internet.  I got it for My old '70 280S.  There was a transmission change I am not sure if it was '68-69 or '69-70.  I don;t know if it included part #'s or not, but a full breakdown.   I could scan and e-mail if you need it.

Allen

[karmannghia60]

That would be great. email to iiivvi@hotmail.com
Thanks

[karmannghia60]

Joe not sure if you received my PMs, not showing in my Outbox for some reason. Please email me your phone number
Rafik
iiivvi@hotmail.com

[karmannghia60]

Back again but different problem now. Two mechanics and two transmissions later, I have a working gearbox except for two problems:

1) Kicking down from 3rd to 2nd as you approach a stop is rough. Shifting up is very smooth though and shifts up at various revs depending on how hard the pedal was depressed so everything seem to be ok there. I knew that my CSS needed adjusting which I did and now 3rd to 2nd is much smoother so I am not worried

2) I have no kick down at all so even if I floor the pedal it won't shift down but will accelerate slowly in the current gear. The mechanic said he tested the solenoid and it works fine but once on the gearbox, it does not work properly obviously

I read the manual section and it looks like the switch under the pedal could also be an issue. I am assuming this should be my first point to check. How do I test it? Can I simply remove it, hook a power supply to it, depress it and see if it turns on?
Thanks
Rafik

[ja17]

Hello Rafik,

Make sure engine timing is correct. Timing issues can cause variations in vacuum which will affect the vacuume modulator and shifting. The length of the linkage rod on the transmission makes a big difference also. Sometimes if it is not correct, kick down will go away and other problems occure. 

The most common cause ofr hard or abrupt down shifts are improper engine linkage adjustments, especially the intake venturi switch.

Yes the kickdown switch is a simple on/ off switch. Whith the ignition on it will send power to the solenoid on the transmission when it is depressed. Make sure that the plug connections are good and clean also.

Remove the side cover on the inside of the car (tunnel) to view the solenoid and linkage working correctly. The transmission linkage can be adjusted from there also if required.