Z3, automatic tranny and subframe issues

[Slingerland]

Hello, all!

I've developed some nerve issues in my left arm and it's making driving my Z3 difficult. Turning right while changing gears is especially hard. I will probably be forced into changing from a 5 speed to an automatic.

Skimming through Autotrader, there are a number of Z3s with automatic transmissions, but most of them have the 2.5 (and larger) 6 cylinder engines. If I understand it correctly, the larger engines contribute more to the subframe crack issues. But my question is: does the automatic transmission help reduce the occurrence of the subframe cracks?

As a FYI, my Z3 is a 1.9 with no subframe issues. I'm perfectly happy with the 1.9; my driving style is cruising through the Ouachita Mountains, not drag racing . And of course, I suppose I could always move up to a Z4, but I like the body style of the Z3 a bit better.

Thank you all!

[Shadowjack1020]

Times change, but when I was looking for a Z3 this spring, almost all the ones I could find were 4-cylinders with automatics. I eventually found a 2.3 with manual and 132K miles, that the PO said he played with on a track sometimes. Having said that, a few trunk floor subframe spotwelds were just barely showing signs of popping. I believe that if the car is a lower-power model, and an automatic, which softens driveline impacts, you should not have to worry about the subframe cracking. Also, if it's low miles, or in pretty nice condition, you know the PO didn't use it very hard.

[kbollox]

I have a 2001 Z3 2.5 with the auto, no seam issues.

Examples are ample and available:
https://www.ebay.com/itm/19548772237...Bk9SR7jl7cKYYQ

[ProductUser]

*Most* of the subframe issues seem to fall under the Z3M variants, but this is not always the case.

[Slingerland]

I have a 2001 Z3 2.5 with the auto, no seam issues.

Examples are ample and available:
https://www.ebay.com/itm/19548772237...Bk9SR7jl7cKYYQ

Thanks! I found a bunch on Autotrader too, all the way down to 40k miles! The 2001 was when BMW went to the 5 speed auto, wasn't it?

[s8ilver]

My 2.8 Coupe was an automatic until 140k miles. Currently 166k with no cracks, but poly sub frame bushings were added.

Sent from my SM-G975F using Tapatalk

[s8ilver]

Thanks! I found a bunch on Autotrader too, all the way down to 40k miles! The 2001 was when BMW went to the 5 speed auto, wasn't it?

AFAIK, that is correct. 2001-2002 2.5 & 3.0 will have the 5 speed. If I had to have an auto, a 3.0 would be it for me.

Sent from my SM-G975F using Tapatalk

[mpire]

The GM slushbox in the Z3 isn't all that bad other than no one services it correctly.

Its the same transmission in the izuzu trooper, rodeo, passport, etc so its not stressed in the Z3 at all.

You have to fill the transmission with the car running and in gear, otherwise it will be a liter low and will have trouble and be hunting and won't stay in gear.

[BimmerBreaker]

The GM gearbox sucks. The 5 speed is a decent gearbox

The subframe issue can occur in any Z3 including an automatic 1.9, it is something to check out before buying any Z3 but not likely to be an issue on an auto that was cruised around town

[KBH22102]

I have a 99 2.8 coupe with the GM 4L30E 4-speed auto. It is a fine trans for DD duty and in Sport mode, actually makes the car pretty peppy. The diff mount issue is more related to the OE rubber subframe bushings wearing out and leading to increased movement of the subframe causing the spot welds anchoring the diff hanger to tear. This wear probably happens more quickly in cars with more power and are driven in a more spirited fashion, but it can happen with any drivetrain configuration.

Replace the bushings with poly units ASAP and you should reduce the risk significantly if not entirely. Randy Forbes himself told me he has not seen a trunk floor failure in a car that had poly bushings installed.

[mpire]

The GM gearbox sucks. The 5 speed is a decent gearbox

The only reason the GM gearbox sucks is because its a slushbox which by definition is undesirable.

However, compared to other automatic transmissions its pretty solid with very few actual issues as long as you change the fluid every 20k and don't pretend the lifetime fill is a thing that can exist on this planet.

That being said, I much prefer the 6 speed getrag over the rubbery 5 speed ZF.

[z3forlife]

I never had any problems with the 4 speed auto in my 99 2.3. Had the fluid checked/topped off twice but never replaced and sold it at 197K miles. It would shift solidly at red line when I punched it every time. On the other hand I bought a Chevy Silverado and noticed slipping at just under 100K. I definitely had the oil/filter changed in it but I’m still not sure how far I can trust it.

[CoconutPete]

Just take a look in the trunk of the car you are thinking about buying.

Impossible to tell from statistics if a 20+ year old car will be suffering from the problem.

Crawl underneath (or get someone else to do it) and look at the diff. mount also.

You could always teach your passenger to operate the shifter while you do the pedals. I started out with my dad doing this - it's how i learned to drive a manual.

[rf900rkw]

Both the 4 and 5 speeds are GM of Europe automatics. The 4 speed is a kludge on top of a kludge adding a 4th gear, lock up converter, and rudimentary electric control on a THM180 transmission, best known in the US as a Chevette trans. BMW did a lot of redesign work on it. The 5 speed is 20 year new technology where GM basically copied a ZF design; a practice they continue to this day.

I've never seen an automatic with a damaged trunk floor.

[rf900rkw]

Old, but good summation.


https://www.youtube.com/watch?v=KDvvTPwvSo8

[Slingerland]

Old, but good summation.

https://www.youtube.com/watch?v=KDvvTPwvSo8

That was funny, thank you!

[Slingerland]

I just wanted to say "thank you" to everybody who posted on this thread. I searched and stumbled onto a 2005 Z4 3.0 with automatic, and bought it. The seller is in Missouri and will transport to me. I should have it in two weeks (we're delaying through next week due to heavy rain where I live.)

It will be a bit sad to say goodbye to my Z3, but the latest dr appt did not go well. Hopefully I can sell it to somebody who will appreciate it!

[CoconutPete]

Best of luck with your Z4 and with selling your Z3.