hard shifts in automatic

[Bahamas]

OK, first issue I'd like to resolve - The auto trans shifts very fast, very early, and very hard. I can select sport mode and shift points move up the RPM range as expected, but in general they are all low. Downshifts seem to work under the appropriate load. However, upshifts (like from 1st to 2nd, or 2nd to 3rd) are really hard, almost tire chirping hard with aggressive throttle. That is not right. It maybe gets a little better when warm, but not much.

So, I'm thinking the basics - change filter & fluid? Thoughts?

[DesktopDave]

I'd definitely go with the basics, can't hurt. I'm no expert on the automatics, but if I had to hazard a guess I'd hop that hard shifts would be related to the clutch pack, 1st gear solenoid valve and/or a partially blocked solenoid filter. More severe problems in the TC, lock-up clutch or line pressure issues should affect all the gears at different RPM.

There's also a kickdown cable adjustment on older transmissions, I'm not sure if that applies to the later model EH (Electro-Hydraulic) 'boxes like yours though.

There is a tidy troubleshooting section in the '89 ETM. Check out pages 2460A-0 for some detailed testing procedures. I believe the Bentley also goes into some detail.

These ZF transmissions (4HP22 EH) are pretty tough. They did have some issues with high RPM in P or N for emissions testing, but ZF upgraded to teflon seals to remediate the problem with the clutch pack. I was browsing and found this official ZF parts reference too. Not incredibly helpful for your problem, but if you needed spares...

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Given the age & condition of your transmission...maybe try some additives? If my '90 535i ever gets back on the road, I've been planning on spiking her ATF fill with a little LubeGuard red. I've heard good reviews, but never actually run it.

[Bahamas]

Electronically speaking, the transmission is perfect, all operations work as expected: sport, 321, kick down, lock up torque converter in 4th gear around 50mph, no fault lights. I'm hoping a simple fluid change will help.

[pgh880]

Electronically speaking, the transmission is perfect, all operations work as expected: sport, 321, kick down, lock up torque converter in 4th gear around 50mph, no fault lights. I'm hoping a simple fluid change will help.

When I first got my 84 635CSI , had the same problem , my mechanic replaced and drained the fluid , replaced the transmission filter . At the end I replaced the transmission w/ a used working unit and , since 2003 it has been trouble free so far . I’m based here in the Philippines, there is no rebuilding facilities like there in the USA . Maybe you can have the transmission rebuilt . Or buy a rebuilt transmission and send them your core .

[shogun]

clean the valve body, new balls in the valve body etc, that often helps. On my website there is a rebuild DIY info, good pics http://twrite.org/shogunnew/files/ja...Valvebody.html

[Bahamas]

Thanks for the info. I'm slow to get around to things, just enjoying the car these days! It runs fine otherwise right now. I took a look at that rebuild page, very detailed! Love the shoebox trick, I usually sketch out on paper and place the bolts on my drawing, but have bumped things on occasion. Anyway, at this point in my life I'm probably not going to tackle a rebuild myself, so either a fluid & filter will work, or a rebuilt unit is in my future. I'll post back when I try something.

[carsnplanes]

I don't think it was mentioned, but have a look underneath and inspect you rear engine/tranny rubber mounts on cross member. Also see how much play you have in your drive-line, if any. Drive shaft, center bearing, diff mount. All can contribute what maybe felt as hard shifting but maybe it's due to slop that the tranny is trying to compensate for. Just a thought.

[SprCpe]

I had/have the same problem with my 89 Auto. When I got the car I changed the Trans fluid and filter, I was not sure when it was done before, the car had just over 100,000 miles. The car still had the hard shift after the change when cold, as soon as it warmed up the shifts smoothed out and it ran fine. There is a link on here or BigCpe from a guy that pulled the valve body out and cleaned everything up, he said it worked great after he did that, I've just lived with it a a minor inconvenience the coupe has 155,000 now and have not had any other problems with the trans.

I'm not a fan of running cleaners through these newer electronic trannys, you never know what will break loose :-) like the others say, check your mounts, check your electronic connections, they can cause huge problems, I can speak from experience lol. If everything else checks good than decide if you want to dive into an electronic trans and do you have the knowledge to do it, me. I decided to live with mine.

Good luck, let us know what you find I would be very interested if there is an easy fix.

CPE

[Bahamas]

Quick update (yeah, it's been a while, sorry!). Tranny fluid & filter changed, plus a few mounts were tired, all replaced. Now things are much better. Not perfect, but with 145k I was not expecting perfect. It's so much better now, good to go. Engine mounts are cracked but not too bad, will do in the spring.