'94 525iT Auto Strange Shifting, and a Ticking

[rizal]

I have a '94 525iT with the GM auto transmission and 109,000 miles. It runs very well except for a couple odd things.
1. When I'm going about 40-70 mph and apply the gas a small amount to accelerate moderately, the rpms rise by about 200-300 rpm then drop back down and lug, so that I have to press harder to generate a full downshift. When I press the pedal hard, it downshifts fine, then shifts normally. It's just under light throttle applications that I get the quick rise and fall of rpms.
2. After the car warms up, I get a ticking sound that varies with engine speed and seems to come from the transmission, not the engine. This ticking arose a few weeks before my last tranny service last November, didn't improve with the tranny service, and has not gotten worse (or better). The tranny service did make it shift more smoothly, though.

Any ideas?
Thanks. Al

[ScottyWM]

Let me guess, when you put it in reverse, does it sometimes take a couple seconds for it to engage too?

[rizal]

It goes into reverse without hesitating. Nice try! Thanks. Al

[ScottyWM]

Reason I ask, is I have the same thing with the shifting at speed (your #1 above), and it seems to go hand in hand with the reverse thing (which I get couple times a month). When I asked here around a year ago about it, someone (Ryan?) thought it was the infamous seal failure. He even had a really good write up and pictures on it. But there wasn't really a good consensus that was the problem. You may want to do a search for it. It sounded too expen$ive to me, so I ignored it. I've put another 20k miles on it with no trouble. But I'd love to get rid of it, it's really annoying on a long trip with the cruise on.

#2 - don't have that noise I don't think. Got other noises, but nothing from the tranny.

[AZ_Jason_S]

Yeah, I have the same problems Scotty described. Ryan posted a technical service bulletin about it awhile back. My reverse problem happens when the car sits for a few days. I think the fluid drains out of the torque convertor into the pan or something like that. Then at 55-60, I get an RPM surging. It is annoying, but I agree it looked too involved to worry about. My solution, I drive 80 MPH. Easy to do here, not many cops, and our rural freeways have 75 MPH speed limits.

[ryan roopnarine]

ummmmmm....not quite


ANYTHING that i mentioned about the a4s 310r is courtesy of Scott council....he wrote up his tranny rebuild (with the emphasis on the pendulum afflicting seal) and provided me with the TSB. i just host the tsb so it doesn't go anywhere, and i've searched for scott's writeup so many times that its far easier for me to find it than most others, and that way it gets contributed to a thread, and have some knowledge of what they are dealing with.......all scott in these cases.

[grave77]

I think you have used ur gear to the bone ... if u have clever service man you need to replace the clutches and sure u need to replace the gear oil and filter ( comes in a kit " O ring + filter and gasket " ) but before you do some u need to check that ur transmission is not hanging on any of the speeds when cold, if it does so your transmission vavle-body is damagd and then u need a new transmission box.

[Elekta]

It could also be a loose valve body. I had tranny flushed and torqued the valve body down, and the slip (mine was at 50mph going slightly uphill) disappeared.

I'd start with a tranny fluid flush and thorough inspection.

[AZ_Jason_S]

You and the service bulletin. The rest of the details are fuzzy....



ummmmmm....not quite


ANYTHING that i mentioned about the a4s 310r is courtesy of Scott council....he wrote up his tranny rebuild (with the emphasis on the pendulum afflicting seal) and provided me with the TSB. i just host the tsb so it doesn't go anywhere, and i've searched for scott's writeup so many times that its far easier for me to find it than most others, and that way it gets contributed to a thread, and have some knowledge of what they are dealing with.......all scott in these cases.

[rizal]

It could also be a loose valve body. I had tranny flushed and torqued the valve body down, and the slip (mine was at 50mph going slightly uphill) disappeared.

I'd start with a tranny fluid flush and thorough inspection.
I'll give that a try. Sounds rational. Thanks to everyone for all the answers. Great site.

[sbcncsu]

Thanks Ryan for keeping that TSB up, it is good to have access to that at all times for folks like Rizal.

Here is the failure that causes the pendulum shift, slow engagement and/or a leak between the main housing and the overdrive housing as seen in my 1995 525iA:

http://www.bimmer.info/bmw/sbcncsu/Overdrive%20Housing%20w%20Gasket%202.jpg

http://www.bimmer.info/bmw/sbcncsu/Center%20Support%20w%20Gasket%201.jpg

Rizal,

What you are describing isn't exactly pendulum shift. It sounds more like a failure to kick down, possible due to a faulty throttle position sensor or perhaps a governor pressure sensor in the trans that isn't up to par. Take it to a reputable independent transmission shop, someone that has worked on Isuzu's, BMW's or Cadillac Catera's. They all share the 4L30E transmission. Have them connect to the diagnostic port to check the sensors and solenoids.

Good Luck,

[rizal]

Thanks Ryan for keeping that TSB up, it is good to have access to that at all times for folks like Rizal.

Here is the failure that causes the pendulum shift, slow engagement and/or a leak between the main housing and the overdrive housing as seen in my 1995 525iA:

http://www.bimmer.info/bmw/sbcncsu/Overdrive%20Housing%20w%20Gasket%202.jpg

http://www.bimmer.info/bmw/sbcncsu/Center%20Support%20w%20Gasket%201.jpg

Rizal,

What you are describing isn't exactly pendulum shift. It sounds more like a failure to kick down, possible due to a faulty throttle position sensor or perhaps a governor pressure sensor in the trans that isn't up to par. Take it to a reputable independent transmission shop, someone that has worked on Isuzu's, BMW's or Cadillac Catera's. They all share the 4L30E transmission. Have them connect to the diagnostic port to check the sensors and solenoids.

Good Luck,