stuck in 3rd gear....please help

[dan02]

hi all,

the transmission's stuck in 3rd gear... like last year I shut off the engine, wait 5 min and back to normal.

This time no deal... I browsed the web + this forum and someone suggest disconnecting the battery, connect the + cable to the - cable.. still stuck..

what else I have to do? please help...

this Saturday I will have the transmission serviced (fluid and filter change). What should I tell the mechanic to do beside servicing the trans.

Since the 1992/735iL has 252K miles (general condition is so-so) is it reasonable to rebuild the trans (about $1800)? Another option is get a used transmission... Please give me some advice...

thanks a lot...

[Steve: 85 735i, 88 735i, 88 735iL]

Triple check battery condition, ground cables and the electrical plug on the side of the tranny. You should call Kirt Koeller and see what he says.

[dan02]

thanks Steve...

I am in So. Cal. I tried to call Kirt Koeller but can't talk to him yet. I will try next week.

[dan02]

something I want to share ... may help someone...

I spent last Saturday with my mechanic... transmission service and test drive... and we find that the kickdown switch is stuck on the low position (ON)... the spring is broken and it didn't come back up...

Since we know that the trans computer react to:

1. the TSP, throttle position sensor
2. the kickdown switch
3. the shifting lever

well when I pull it back... the car ran perfect... at home I play with that switch a bit and now it's in the limp mode again... I think the internal part of the switch is broken... I order the part...

let's see what will be next...

[Highline]

Shogun's E32 Tech Tips: http://tridem.han-solo.net/auto/erich/auto.htm

[dan]

hi Highline...

he is the report...

we replace the kickdown switch...

- NO GO

- on the scope it show Fault on "Throttle Sensor Switch (TSP + Kickdown sitch + Torque Converter..

- we tried to clear those faults ... and RE_CHECK..

- same for about 5 times..

- on the final try nothing came up... evrything is clear..

the car is STILL on limp mode, so I drove it home and on my way I stopped at the library, park the car and came bacl after 30 min... and LO and BEHOLD... the limp mode is gone...

my guess.. is something wrong on the TRANS computer... my mechanic think it's the solenoids...


i want to have a loo on the trans computer... where's located and hoe to do safely/


thanks...

[Steve: 85 735i, 88 735i, 88 735iL]

If you want to try swapping with another, just make sure you get the right one, they are different between years and with/without EML. If your car does not have EML, I think your computer should say "HI" on it.

[PatrickC88750]

[dan02]

thanks Steve and Patrick...

once I get to that computer and open it up, is there spot(s) to look for crack or something..? I mean the most suspected point pint and also is there any special recommendations in order not nreak it

many thanks in advance,

[PatrickC88750]

on the other board. That thread covers a specific trace below a big capacitor that you should inspect. bim mer board dot com.

[dan02]

so I took that Trans Computer out, anw what I see is this:

- it's already being opened (the tabs and scratches around them). So then I now know that my car has a problem with limp mode in the past and also it's not the trans, it's something about electronic and sensor..

- the electronic board of the Trans Computer, there is no trace or sign of repair (no new soldering repair spot).

- on the soldering side, all the soldering spots are very dull, not shiny as supposed to.

- there is a layer of gray/white soldering oxidation... I clean it carefully with Q-tips and WD-40...

- I use an Agfa x8 loupe to look, there is no crack or bad soldering spot at all.

- the component's side looks OK, clean .. no dust...

- I supposed the board was replaced.. but why don't they replace the whole unit instead of the board..? aaarghhhhh...

seeing that I am even more confused...

- the limp mode is intermittent

- sometime it lasts a week... sometime it lasts a day...

Now I think it's the solenoids.... I will bring the mater to kirk koeller if I can talk to him..