advice to drain atf via cooler pipes?

[haydent]

I've done a few standards changes but want to try and drain as much old fluid out this time as possible.

Read some mentions about possibility of doing it this way but just wanted to check out was ok to let out pump itself dry like this?

What point would be best to disconnect it at?

[jafir]

It's a bad idea to let it pump dry. If you were able to assure new clean fluid made it in the other cooler line, you'd probably be ok. I've seen some shops that have special equipment that they use to exchange fluid like that.

[SiddersC]

If your trans has a few K's on it, it could do more harm than good changing all the fluid in one go.
Plenty of vehicles drive in to get trans flushes and dont drive out.

If your fluid is not burnt and the filter is clean, I would just leave it, if of course you dont have any issues with it?

[haydent]

That is the problem. I did a full change 12 months ago. Pretty much first ever and was black, as well the plastic tubing around the wiring inside was all melted. Must have been over heated. It was running ok though.

Since then though been having trouble as you warn off. And been trying different things to fix it, not that there are many options.

A couple of bottles of Lucas additive worked the best and stopped it not shifting into 1st in the mornings. But it seems to have degraded further now as that's happening again plus its not shifting into 4th/od regularly until you rev it real high, that's how we get out to change out of first too when it sticks...

Anyway bought a couple of bottles of transmax as a last attempt but wanted to get out as much of the old fluid as possible. Maybe even running some cheaper stuff through first too do this better.

Also not sure if there's much a tranny place could do either, except for the machine you mention?

[OffTrack]

I haven't done it but I've read that you can pull the return line from the transmission oil cooler. The idea seems to be that if you rig up a hose/reservoir arrangement to the return line you can keep up a flow of fresh fluid to the tranny while the old fluid is pumped out via the oil cooler. It sounds good in theory, and I think a few members may have done something similar.

[SiddersC]

It could do more harm than good, but as you are having these problems, and a rebuild is on the cards, give it a go and see how it turns out.

Doesn't sound too promising though.

Good luck with it!

[haydent]

Yeah, I think a rebuild unit is going to be the real fix as just now towing a mild weight up some hills the transmission temp light has been coming on when it never had before (since I've owned it)...

[d2dave]

I haven't done it but I've read that you can pull the return line from the transmission oil cooler. The idea seems to be that if you rig up a hose/reservoir arrangement to the return line you can keep up a flow of fresh fluid to the tranny while the old fluid is pumped out via the oil cooler. It sounds good in theory, and I think a few members may have done something similar.

I have done this on numerous occasions. Just make sure that you have a good pump and plenty of oil. I remove pan first and clean/do filter. Then refill. With rear return line disconnected, connect some clear hose to it and put other end in collection container. Start the motor and then pump in oil as the old stuff comes out of the cooling line.

This was the method we used when ever fitting a reco auto as a way to get old oil out of the cooler. As for flushing the auto, it works well as the oil that you can't otherwise drain is what is trapped in the converter.

When the engine is running the feed from the auto to the cooler is via the converter, as this is where the hottest oil is.

As for the best place to disconnect, I usually do it at the auto

[OffTrack]

SiddersC the issue is neglected changes rather than age of the transmission. The auto is designed to have the oil changed every 40K km or possibly even 20K Km if you assume the service schedule's arduous usage "transmission oils" category covers the auto. It seems that problems post-change occur when fluids changes are not done regularly.

Haydent, did you do the filter when you did the last fluid change? I'd be very tempted to do the filter again even if you did it last change.

[d2dave]

I actually had a think about this after my last post. Anyone having trouble with an auto after changing the oil would have had a dodgy auto anyway. Changing the oil if done properly can only improve things, not make them worse.

[haydent]

I did change the filter the first time, I'll do it again as they are cheap. Whether a box is roached or not there is allot off people saying changing old oil all of as sudden is as risk and is say it's likely this happened to me but I do agree I think the box had been cooked at some stage but there where no symptoms till I changed the oil filter for it first time...

[SiddersC]

SiddersC the issue is neglected changes rather than age of the transmission. The auto is designed to have the oil changed every 40K km or possibly even 20K Km if you assume the service schedule's arduous usage "transmission oils" category covers the auto. It seems that problems post-change occur when fluids changes are not done regularly.

Haydent, did you do the filter when you did the last fluid change? I'd be very tempted to do the filter again even if you did it last change.

I would say that since the oil was black on the initial change, that the change intervals have been neglected?

[OffTrack]

I did change the filter the first time, I'll do it again as they are cheap. Whether a box is roached or not there is allot off people saying changing old oil all of as sudden is as risk and is say it's likely this happened to me but I do agree I think the box had been cooked at some stage but there where no symptoms till I changed the oil filter for it first time...

The problem is letting the fluid get too old/dirty in the first place. The new fluid contains detergents which can loosen sediments and particles which have the potential to clog the passageways and valves in the auto.

In theory it is possible to overhaul the valve block, and this would be very likely to solve the issue. RAVE actually details removal/refit of the valve block but not overhaul.

From what I can gather on BMW forums it is possible to order all the parts required to do the valve block overhaul. I guess it is just filed under "too hard" for most people.

BMW E32 valve body rebuild - YouTube

cheers
Paul

[OffTrack]

I would say that since the oil was black on the initial change, that the change intervals have been neglected?

Defintely a good indicator. Problem is that the first most owners of second or third hand D2's know of the lack of servicing is when the fluid is drained.

[d2dave]

99% of valve body overhaul is just a clean and make sure that the valves are free. Not sure about ZF's but I have overhauled a lot of the old Borg Warner three speed autos and a few Ford C4's. With the BW auto there are no parts needed for the valve body and the C4 has two rubber balls and from memory a gasket for the two halves.

Anyone who is mechanically minded could easily do this. It is just a case of having a very clean work environment.

[haydent]

Can in get the valve block out with the tranny still in ?

[OffTrack]

Yes. It's procedure 44.40.01 in RAVE. I've attached the relevant pages.

As I mentioned previously there is a surprising amount of work that can be done on the Auto without dropping the transmission.


BMW used the 4HP22EH on the E28 at least so there is a bit of information floating about on BMW forums and sites.

This isn't necessarily for the 4HP22 but is a useful looking guide to what is involved in overhauling a valve body:
http://www.e38.org/e32/e32%20transmission%20valve.pdf

This pdf contains an article on things to look out for when working on the 4hp22:
http://e28-535i.com/524td/TransTec%20article%20on%20ZF%204HP22.pdf

[haydent]

Great thanks. I'll definitely follow this up when I've got the dump off to change the filter and oil.

[haydent]

looks easy !

from pdf:


As for my BMW, it has never shifted smoother. My problem of the
transmission not going into reverse and of hard shifts when going from Drive to Fourth
are a thing of the past.

[haydent]

well because i didnt have the rebuild kit and time, yet wanted to try and get things a bit better i just flushed the oil & put in new transmax z with new filter. it seems to be better though time will tell, shifting is a little rough still but the real tests will be the cold morning starts.

i did it like this:

drain fluid normally
remove pipe at point near filler plug (easiest to get to) (dont loose the o-ring in there as i did)
start car, wait till fluid stops being pumped out into oil catcher (not much)
refit hose, put in spare fluid i had, there was enough to make it overflow (car not running)
run car for bit through gears
remove hose, start car let it pump everything out again
refit hose
remove sump and replace filter
refil with atf (transmax z in this case, took one bottle)
start car, run through gears, put TC in neutral, Tranny in D and top up while running.

[haydent]

Oh well, same problems still...