manual transmission leak

[bjudd]

My 280 manual tranny has a leak.  It began two days ago, the day after I drove it aggressively for about 15 miles.  By aggressively I mean accellarating quicklyand shifting in the higher rpm range.  The leak is significant - not just a few drops.  I can't say how much because it is going onto paper on a matt.   Anyway, I'm feeling dumb for pushing it and anxious about what it might be.  I plan to lift it this weekend and would appreciate input about how to evaluate.  It is the zf 5 speed.

thanks



bjudd
1969 280 SL 5 sp

[ja17]

Hello  bjudd,

Check the fluid level first. If you are lucky it may just be over filled and foamed out the vent during the brisk drive.

Joe Alexander
Blacklick, Ohio

[Benz Dr.]

The vent is at the back and top of the trans on the 5 speed. They only hold about 1 liter of trans fluid so you don't ever want to run them low. Those parts that are still available are VERY exspensive.

The two places that you will find a leak are the front and rear main seals and also the front and rear covers. The top cover is much less a problem and I'ver seen the seal around the speedo drive leak on some cars.

Dan Caron's
 SL Barn
benzbarn@ebtech.net
 slbarn.mbz.org
  1 877 661 6061

[bjudd]

what size is the hex drain & fill plug for this tranny?    home depot and the local tool place don't have sets this large.  looks like 17?  need to order it.

thanks

bjudd
1969 280 SL 5 sp

[Raymond]

If you're in a major city, Napa probably has a full assortment of hex wrenches in stock in their warehouse store.  That's the case here in Jacksonville.  I think the plug on my 4-speed is 14mm.

And, another thought. Are you sure it's transmission fluid and not brake fluid from the clutch slave?  If if popped up that suddenly, it could be the hose.

Ray
'68 280SL 4-spd Coupe

[bjudd]

"I think the plug on my 4-speed is 14mm. "

I borrowed a friends "special" 14 and it is small by several sizes.  I'll check with Napa for the larger sizes.  I'll check the clutch slave too but the fluid had a reddish tint which i believe is ATF used in the tranny.

thanks

bjudd
1969 280 SL 5 sp

[Raymond]

Yep, if it's red it's ATF.  Oh well, I was hoping for an easy fix for you.  

You're lucky to have the 5-speed.  It's worth extra care.

Ray
'68 280SL 4-spd Coupe

[rwmastel]

quote:Originally posted by bjudd

what size is the hex drain & fill plug for this tranny?    home depot and the local tool place don't have sets this large.  looks like 17?  need to order it.

Side Note:  If you know what you need, lots of great tool are available at http://www.samstagsales.com/

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[bjudd]

I found the 17mm allen and it is correct for the fill/drain plugs.  she was missing about a third of a quart.  (it had fresh ATF in November) There was no leak before the last drive so what it lost came out while not being driven.

also got the zf manual from the Maserati site that George Des spoke of in another post.  It helps clarify that I won't be opening this tranny, but when someone does, it will be handy.

"it may just be over filled and foamed out the vent during the brisk drive."  - Joe  

can you overfill?  doesn't one fill to the bottom of the fill plug opening?  Unless the car was not level it seems it would not overfill.  Or, is the fill line below the bottom of the fill plug opening by a finger or so??

thanks

bjudd
1969 280 SL 5 sp

[rwmastel]

quote:Originally posted by bjudd

"it may just be over filled and foamed out the vent during the brisk drive."  - Joe  

can you overfill?  doesn't one fill to the bottom of the fill plug opening?  Unless the car was not level it seems it would not overfill.  Or, is the fill line below the bottom of the fill plug opening by a finger or so??

JBUDD,
I really hope you are talking about the fill  plug on the differential, not the transmission.  Your original question was about transmission fluid leaking and now you're talking about filling up to the top of the fill plug.

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[bjudd]

Rodd -

i am speaking of filling the transmission through the fill hole on the side of the transmission.   ... "to the bottom of the fill plug opening".  I just received a zf manual that I ordered from the Maserati web site and this appears to be the correct way to do it.  Pump the ATF into this side hole until it starts to dribble out the side; let it level off and then put the plug back.  

Since topping off the fluid.  I have been able to drive only twice and the slow leak is almost certainly coming from the rear seal.   Anyone have a step by step description on replacing the rear seal?  (I've been told it would be the same as for the 4 sp.) The manual is helpful but geared to the complete rebuild that I sure hope isn't in store.   It still shifts very smoothly.

bjudd
1969 280 SL 5 sp