Hi all
My 88/300E has only done this on 3 occassion...going down the road the tranny goes free for a second and rpm increases and once i let go its normal and works perfect.Any suggestions it has 138,000 km's on it and has had mb service performed as specified.
Another problem is after driving for 5-10 minutes it also (only happened twice)seems like its starving of gas and after a good rev up is fine..can it be injection problem or starvation/etc.

All responses will be appreciated.
Besides this its a real gem!

[This message has been edited by AV (edited 04-24-2000).]

[This message has been edited by AV (edited 04-25-2000).]

Do you know which gear you're in when it starts to freewheel? Sounds like your losing oil pressure somewhere? Is the trans fluid level on spec? Problem with power loss could be a number of things. Most likely is a fuel pump that's starting to pack it in.

------------------
Jeff L
1987 300e
1989 300e
1987 BMW 325

[This message has been edited by jeffsr (edited 04-24-2000).]

300E is notorious for its leak from the tranmission, sounds like someone had let the transmission fluid ran low before and worn out some of the clutches. Keep checking the fluid and rebuild it if it gets worse. Good Luck!

chupr98

I think that the gear freewheels in 3rd or 4 th gear as by then its already around 60kph.

Could the power loss be due to injectors gumming up or maybe a clogged gas filter?

How can i check the fuel pump?

[This message has been edited by AV (edited 04-25-2000).]

Lots of possibilities with the tranny, including both under and overfilling.

If fluid level is right I would tighten the modulator pressure and quicken the shifts hoping to keep your shift overlap problem to a minimum. A car could be driven like that for years (I've seen them) without further problems.

The problem of "Flairing" between shifts has to do with the fluid dynamics of disengaging one element (here a servo driven band) and engaging the next device (in both 3rd and 4th the action is a clutch pack filling and engaging). The fluid pressure, the spring rates of valves, the sealing capacity of old lip seals, the chamber capacities of both the elements (gets larger as the devices wear) and the their accumulators, the spring rates of the accumulators, and the filling oriface diameter all play a part in assuring that one device's engagement process is initiated sufficiently before the others release as to not leave a gap. All these activities take time. The idea is to do this in symphony.

If finessing the modulator and control pressure doesn't get it, one last ditch effort can be made if rebuilding is inconvenient. Change your fluid and use an additive designed to clean varnish and soften seals. Either of these conditions can be the real reason for the flair. A little seal leakage can delay the clutch filling enough that the disengagement of the band occurs first and a flair occurs.

As to fuel pump checking, the actual test involves installing a gauge ahead of the pressure regulator and disconnecting the fuel return line. A minimum pressure should be maintained while a minimum quantity is caught from the return. In other words the pump should deliver around 70psi while delivering around a quart or more a minute.

We do further testing by the use of a remote fuel gauge while driving. The pressure should stay very constant. The actual pressure is less important than the stability of that pressure.

I would definitely replace the fuel filter if its been a while and check what is in it(Blow in the reverve direction into a clean container - stay away from sparks). You can expect a lot of crap but not water!!

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician



[This message has been edited by stevebfl (edited 04-25-2000).]

Steve, or any other tech,
Can you recommend a specific trans additive please?
-Nick, soon do to next trans service...

[This message has been edited by Nick Jamal (edited 04-28-2000).]

So, is it wrong to add to a post just to get it back on the first page?

Just did a Tranny service at a MB dealer in Ajax Ontario and when i mentioned to the tech about Vacuum and modulator pressure adjustment he seemed bewildered and for a second i got the impression that he did not know what it was!and then he said it did not apply in my case.
This is a new MB dealership and i hope that these guys are qualified.
Also replaced the O2 sensor as the light came on
Anyhow lets see how it goes as it seems to drive better with new o2.

Thanks for all the invaluable help and comments received here.


[This message has been edited by AV (edited 04-28-2000).]

[This message has been edited by AV (edited 04-28-2000).]

Modulator and control pressure aren't a factor on any of the new electronic transmissions. They came out in 1996.

Modulator adjustments aren't a factor in pre-1980 diesels either or any pre-1970 trannies. All others have some version of both.

------------------
Steve Brotherton
Owner 24 bay BSC
Bosch Master, ASE master L1
26 years MB technician

[This message has been edited by stevebfl (edited 04-28-2000).]

Just got a tranny service and noticed the same sympton again when it was cold.
could anybody give me more advise.It only happens for a split second and then noting all day long.

Thanks for all input.

[This message has been edited by AV (edited 05-09-2000).]