Auto transmission help

[Griffinroydonal]

Hello, I am having a problem with my 87s4 Transmission slipping and wanted to know where to look to check fluid level. I was told my transmission was in the rear- I had that figured out MP-Dano. Thanks. I have not had any issues and was not familiar with the Auto transmission. Can anyone here be a little more helpful please ?

[MPDano]

dC AutomotiveOver 140,000 square feet of new and used Porsche parts



This is on a 78-82. Not sure on a later one.

[MPDano]

87-91 shows a larger reservoir. It's there man. Guides don't lie. Around part #39

[neil30076]

Leo beat me to it - the last diagram shows the reservoir for the fluid - you need to either check out the owners manual, or the shop manual, for the correct procedure for topping off the level, do it wrong and you can cause major problems !

[Griffinroydonal]

pictures are just what I needed - Thank you very much !!

[153bigblock]

Originally Posted by neil30076

Leo beat me to it - the last diagram shows the reservoir for the fluid - you need to either check out the owners manual, or the shop manual, for the correct procedure for topping off the level, do it wrong and you can cause major problems !

Yes, Mercedes transmissions are sensitive to overfilling. Make sure your tranny is good and warm before you check it. Run the car for at least 20 minutes on the highway before you check level. Also, pm me your email address and I will send you a PDF of the Mercedes trans manual (722.xxx) and a diagnostic for identifying your issues.

Slipping or "flaring" can be as simple as a filter and fluid change, modulating pressure issues or the beginning of B2 band issues among other things.

[MPDano]

Originally Posted by Griffinroydonal

pictures are just what I needed - Thank you very much !!

No Problemos. Also, make sure your car is at operating temp (warm). My OB (1981) reservoir has a notch on the metal bracket next to my reservoir which is where you want your fluid level to be. Not real sure where I read this but the level is checked with car at idle and on level ground. I know it's dangerous but this is how I check mine. I wish I knew where to reference this, but someone can chime in to make sure this part is correct.

[Landseer]

Same way I check it, must be running. Can be done safer on 4 jackstands
To fill, I clamp a funnel to a 5/8 clear tube, zip tie to the fuel filler door
Snake other end behind the tire past the crossmember and to the filler hole.
Keep dirt out, might require some precleaning before opening the cap.

Filter change might also be a good idea.

What kind of slipping is it doing? Every shift, all the time, only in reverse, how?

[Griffinroydonal]

Car will pull off from a light with very little throttle and not slip. Hammer down on it and it slips in every gear. When you let off the gas the engine rpm drops and transmission catches up. Drive it easy and there is less slipping but if you push it there is a problem. This car had a New Porsche trans axle installed due to problems before I bought it. When more problems started the PO sold the car rather than fool with it. I am draining fluid and changing filter today to see what happens. I have been lurking post for a transmission for the last few months and will see what happens.

[153bigblock]

From the transmission manual:
TROUBLE SHOOTING
TRANSMISSION SLIPS IN ALL GEARS
Incorrect modulating pressure. Modulating pressure control
valve or pressure relief valve is dirty or sticking. Vacuum line to
transmission vacuum capsule clogged or leaking. Working pressure
control valve dirty or sticking. Low working pressure. Defective
primary pump.
Transmission Slips When Starting Off In 1st Or 2nd (Reverse
Is Okay)
Band B-2 shift valve sticking. Band B-2 piston worn or
damaged. Band B-2 adjusted incorrectly or worn or damaged. Adjust
brake band B-2 by installing a longer thrust pin (if necessary). If
transmission operates properly with selector lever in "2", but not in
"3" or "D" position, one-way clutch may be slipping.
Transmission Slips In 2nd Gear Or Shifts From 1st To 3rd Gear
Check control valve B-1 for ease of operation. Replace valve
body (if necessary). Remove and install brake band piston B-1, check
sealing ring and replace (if necessary). Replace brake band B-1 and
thrust body for B-1. Command valve binding.
Transmission Slips During 2-3 Upshift Or Slips Initially,
Then Grabs Hold
Check modulating pressure and adjust (if necessary). Check
for temperature throttle installation (if equipped). Valve body worn
or damaged. Replace valve body (if necessary). Replace inner plates of
clutch K-1 or recondition clutch (if necessary). Check front cover
Teflon ring.

[Danglerb]

Originally Posted by Griffinroydonal

This car had a New Porsche trans axle installed

New as in the Porsche dealer had one sent in from Germany for $10k, or new as in rebuilt, or new as in new to this car fresh from the bone yard?

Sometimes the safest bet is to ignore anything the previous owner tells you and start fresh.

[MPDano]

Originally Posted by Danglerb

...or new as in new to this car fresh from the bone yard?

OMG, that's hilarious!

Or if you start from a wreck like I did, fresh fluid and filter made a huge difference. My only issue with mine now is the front seal has a small leak, which I need to drop the tranny for.

[Landseer]

Not hard to drop them, considering all the other work you've done especially.

I just replaced a B2 piston with the upgraded version. That service can be done with the transmission in the car, BTW.

I'd drain the fluid from pan and torque convertor on this one. Refill carefully, get the fluid level above the lower mark when idling. (When you turn off, by the way, the reservoir fills completely up, so don't judge it unless idling)

You can check the vac by attaching a gauge back by the trans, starting car, reading gauge.

You can pull the cap on the modulator valve, flip out the key, and put a turn clockwise on it to increase pressure also. (I've read this is just a shot in the dark adjustment, Best to set-up via workshop manual with pressure gauges, watching responses while driving and shifting)

[Griffinroydonal]

The PO was anal about documentation on the Porsches he owned. I was supplied with a binder that contained documents and receipts for any and all service and repairs made to this car since it was purchased new. The reciepts are there for a new crated transmission from Porsche. There is also a signed letter from the service director of the Porsche dealership to Wolfgang Sander, District Service Manager for Porsche Cars of North America. The letter spells it all out so that rules out "Bone Yard" parts or rebuilt transmission. I believe all documentation to be true and correct with little or no reason to question what I was told by the PO.





There was a transmission swap made at the dealership after the new transmission was installed. At this point I have no idea what the hello will happen next. I have the filter kit as of today and will drain and fill asap. There is an auto transmission place near by that also builds transmissions for race cars and will take a look at. I would like to have a transmission that would put the power to the pavement as the car has been chipped, has headers , solid motor mounts , and a few other upgrades. I do thank you all for your time and attention with this post.

[MPDano]

Originally Posted by Landseer

Not hard to drop them, considering all the other work you've done especially.

I just replaced a B2 piston with the upgraded version. That service can be done with the transmission in the car, BTW.

I'd drain the fluid from pan and torque convertor on this one. Refill carefully, get the fluid level above the lower mark when idling. (When you turn off, by the way, the reservoir fills completely up, so don't judge it unless idling)

You can check the vac by attaching a gauge back by the trans, starting car, reading gauge.

You can pull the cap on the modulator valve, flip out the key, and put a turn clockwise on it to increase pressure also. (I've read this is just a shot in the dark adjustment, Best to set-up via workshop manual with pressure gauges, watching responses while driving and shifting)

The front seal can be done on the car? Yes?

[Landseer]

That's a Mr. Merlin question.

But I think you want to pull it out.

And that's really not hard. I was very aprehensive at first, but with a trans jack its doable.

[Danglerb]

As I read the letter it says the previous owner found a core, a third party did the rebuild, and that was installed in the car and worked.

Pretty clearly the dealer was lost working on it, so back to step one, ignore what the PO says and start fresh.

How far are you from Steve Catteano?

Master Tech Transmission - The Premier Automotive Specialist of the Hudson Valley

[neil30076]

and the shop was a ford lincoln mercury & hyundai - isuzu specialist - smart choice!

[Griffinroydonal]

I am following your suggestion and going back to square one. I will wait a couple of days as it is 17 degrees here tonight and there is not enough heat in the shop

[MPDano]

Originally Posted by neil30076

and the shop was a ford lincoln mercury & hyundai - isuzu specialist - smart choice!

OMG! Neil is right. I just saw that on the Letterhead. Now you have no choice but to disregard that work. Square Uno my man.