Very Hard to shift

[Bilito]

In my 97 Z3 6cyl it is very hard to shift gears, especially from neutral to reverse, I was wondering what could be the cause, could it be the syncro mechanism is bad or all the gears are going bad. one in gear, any gear, it run very smooth.

How big a deal is it to pull the tranny and replace the gears?

[bluptgm3]

Can’t tell much from your brief description.

Have you run fresh fluid/bleed the clutch line?

Also you might consider replacing the short rubber line with a stainless steel braided line, as the rubber line degraded over time.

Also, there is a clutch delay valve in the system that dampens the clutch release and take-up, so don’t expect fast shifts, slow and precise is the name of the game here. Folks often remove this BMW ‘feature’.


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[zellamay]

It's not bad gears or synchros. Many people with perfectly good transmissions have these stiffness problems. If your clutch is engaging/disengaging at the right places, the first thing to do is tranny fluid. Seems like RedLine is the choice, but one pundit says plain old Dex3 is fine. I put Royal Purple in mine when I got about 2 years ago. It has always been stiff going into reverse (and here's something odd: when cold, only the first time into fifth). It has problems finding 3rd sometimes, so I'm changing to Redline, and installing a stainless steel clutch line, in the next week or two. See thread below for some comments: https://www.bimmerforums.com/forum/s...unts-what-else ( ... just for the record, you would not "replace the gears". You would get another tranny.)

[pine1000]

My transmission is hard to shift into 5th, and really doesn't feel right going into any gear. It does get a lot better in the summer after a full day of driving.

I've changed the slave cylinder, slave cylinder hose, rebuilt the shift linkage, and replaced the fluid with pentosin and now with royal purple.

My next step will be to replace the shift pins.

[zellamay]

My transmission is hard to shift into 5th, and really doesn't feel right going into any gear. It does get a lot better in the summer after a full day of driving.

I've changed the slave cylinder, slave cylinder hose, rebuilt the shift linkage, and replaced the fluid with pentosin and now with royal purple.

My next step will be to replace the shift pins.

My experience, and at least 2 others (see thread: https://www.bimmerforums.com/forum/s...unts-what-else ) are that Royal Purple might be causing the problem, or at least not helping. As advised in that thread, I'm switching from Royal Purple to Redline. Shift pins is a huge job. (If I ever do that, I'll also replace clutch.) Trying Redline seems worth a try.

[pine1000]

My experience, and at least 2 others (see thread: https://www.bimmerforums.com/forum/s...unts-what-else ) are that Royal Purple might be causing the problem, or at least not helping. As advised in that thread, I'm switching from Royal Purple to Redline. Shift pins is a huge job. (If I ever do that, I'll also replace clutch.) Trying Redline seems worth a try.

The Royal Purple SynchroMax was a definite improvement over both the Pentosin and the BMW fluid for me. I can't imagine that switching to another fluid is going to completely fix the sticky shift pins.

The pins don't seem like a super huge job. You do have to pull the exhaust, heat shield, and drive shaft (did that before when doing my subframe bushings). Pulling out the transmission will be new for me.

[zellamay]

The Royal Purple SynchroMax was a definite improvement over both the Pentosin and the BMW fluid for me. I can't imagine that switching to another fluid is going to completely fix the sticky shift pins.

The pins don't seem like a super huge job. You do have to pull the exhaust, heat shield, and drive shaft (did that before when doing my subframe bushings). Pulling out the transmission will be new for me.

I've seen fluids make a huge difference in both trannys and diffs. Each to his own. Please post results.

[Bilito]

This tranny cannot be rebuilt?
Out in New tranny fluid that was recommended here some months ago
Problem is I am having rough shifts, it seems to have difficulty with with each shift
I used to have Nissan 300Z and it shifted as smooth as glass and as fast as I wanted

[nevan]

I think there are plenty of great advises already. But to add my two cents, start with something simple and *inexpensive* like replacing tranny fluid or bleeding the clutch line to make sure there is no air. My slave cylinder nozzle let air in which caused hard shifting with occasional grinding (gradually gotten worse over time).

[zellamay]

This tranny cannot be rebuilt?
Out in New tranny fluid that was recommended here some months ago
Problem is I am having rough shifts, it seems to have difficulty with with each shift
I used to have Nissan 300Z and it shifted as smooth as glass and as fast as I wanted

Of course it can be rebuilt. A used tranny just makes more sense for most people. Costs far less, and it has been proven to work.
What fluid is in it? Either the fluid and the SS line might help.
...... I had 2 of the 300ZXs. A very pleasant car to drive. My Z3M is more fun, but the Nissan was smoother, quieter, and more powerful.
If I still did a lot of Phoenix to LA trips, I'd want that car over the BMW.

[bluptgm3]

This tranny cannot be rebuilt?

Well there is this -
https://www.bimmerworld.com/Drivelin...nsmission.html

Or this basic rebuild -
http://metricmechanic.com/ultimate-t...sion-rebuilds/

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[magnetchief]

Had a similar hard shifting issue.
Solved when I replaced the short hydraulic hose.

This was what came out of my car.

I figure it was bulging like an aneurism every time I stood on the clutch.




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[z3forlife]

How does it shift when the motors off. How far up from the floor does the clutch engage

[Blacklane]

Often with these cars, shifting problems are actually clutch problems. The DOT 4 brake fluid absorbs water much more than DOT 3 used in American cars and becomes compressible with age. Then there is the clutch line problems shown above. That can be solved with an aftermarket stainless-steel braided clutch line.

The way to diagnose clutch problems is to shift with the engine turned off. If it shifts well, then the problem is the clutch mechanism, if not, it's the shift linkage or transmission.

Bleeding the clutch slave cylinder must be done properly. The slave cylinder has to be removed, the bleed screw opened, and the plunger compressed. I just press it against the bell housing, but BMW makes a special tool to do it. Then close the bleed screw, release the plunger, and repeat a few times, checking the fluid level often. BTW, you should also consider bleeding all of the brakes with fresh fluid. It will greatly improve the brake feel.

[Mr Bingley]

The #1 most likely culprit bar none is the rubber clutch line. It is a fine idea to replace the transmission fluit as well, but replacing the rubber clutch line will most likely solve the problem. Here is a thread on the subject:

https://www.bimmerforums.com/forum/s...1#post27938021

[rasmuw]

It's not bad gears or synchros. Many people with perfectly good transmissions have these stiffness problems. If your clutch is engaging/disengaging at the right places, the first thing to do is tranny fluid. Seems like RedLine is the choice, but one pundit says plain old Dex3 is fine. I put Royal Purple in mine when I got about 2 years ago. It has always been stiff going into reverse (and here's something odd: when cold, only the first time into fifth). It has problems finding 3rd sometimes, so I'm changing to Redline, and installing a stainless steel clutch line, in the next week or two.

With the exception of going into reverse, your description matches mine. Like you, I have Royal Purple in my gearbox. The previous owner had already installed a stainless clutch line and a new clutch. Since I didn't know the history of the transmission oil, and had heard such good things about Royal Purple from the T5 folks, I changed the gearbox oil. If possible, install the stainless clutch line first and test the results. Then change the Royal Purple to Redline. I'll be interested in your experience.

[rf900rkw]

Often with these cars, shifting problems are actually clutch problems. The DOT 4 brake fluid absorbs water much more than DOT 3 used in American cars and becomes compressible with age. Then there is the clutch line problems shown above. That can be solved with an aftermarket stainless-steel braided clutch line.

The way to diagnose clutch problems is to shift with the engine turned off. If it shifts well, then the problem is the clutch mechanism, if not, it's the shift linkage or transmission.

Bleeding the clutch slave cylinder must be done properly. The slave cylinder has to be removed, the bleed screw opened, and the plunger compressed. I just press it against the bell housing, but BMW makes a special tool to do it. Then close the bleed screw, release the plunger, and repeat a few times, checking the fluid level often. BTW, you should also consider bleeding all of the brakes with fresh fluid. It will greatly improve the brake feel.

Sorry, no, it's the other way. DOT4 absorbs water a lot LESS than DOT3. American cars that have ABS use DOT4.

Brake fluid is not compressible. Water is not compressible. The combination of the two is not compressible... *until* you heat to near the boiling point of the water This will happen in the brakes in the form of localized heat in the calipers. It will not happen in the clutch. Or should not. If you manage to get clutch fluid to 200F... I don't want to know what you're doing.

[Vintage42]

Been saving forum posts on hard shifting for 6 years. At 32,000 miles I changed from original Dex3 to Royal Purple. Over the next few years I changed the line to stainless steel. Had the fluid bled twice. And installed a Mason clutch pedal. The result is very little difference.
The move from Neutral to 1st or Reverse has never been as soft as I would like, while all the other shifting has always been easy.
I have come to believe that there is no difference in the fluids of the same viscosity, regardless of brand. Dex3, BMW, Pentosin, Royal Purple and Redline are same viscosity.
For a difference in feel, try the more viscous AMSOIL, or the even more viscous gear oil. But they won't ease the shift from neutral, and all shifts might be harder in cold weather until the transmission is warm.
I think the hard shifting from Neutral to 1st or Reverse lies in the shift mechanism, the ball and bushings of the linkage. I don't think I am pushing synchros, but am pushing through linkage, and it's normal.
I have not heard anyone say that their Z3 goes from Neutral to1st as easily as it goes up through the rest of the gears.

[Blacklane]

Sorry, no, it's the other way. DOT4 absorbs water a lot LESS than DOT3. American cars that have ABS use DOT4.

Brake fluid is not compressible. Water is not compressible. The combination of the two is not compressible... *until* you heat to near the boiling point of the water This will happen in the brakes in the form of localized heat in the calipers. It will not happen in the clutch. Or should not. If you manage to get clutch fluid to 200F... I don't want to know what you're doing.

Actually, both water and brake fluid are compressible. Here is a chart that shows the compressibility of Castrol SRF fluid, which is DOT 4 fluid. Castrol_SRF_compressibility.pdf
There are many charts on water compressibility as a function of temperature and depth (just google it), but in general, around room temperature and sea level, it's below the 5E-4 line on this graph, indicating that brake fluid is much more compressible than water, which is also compressible.

Your argument about heat is true for Undissolved water in brake fluid. That would be literal gas bubbles. The compressibility is a result of dissolved water. DOT 3 and DOT 4 absorb water as they age, but this water is dissolved, that is, it does not change the volume of fluid, but it does change the characteristics.

For further insight, look over this article by Torque Brake Fluid (http://torquebrakefluid.com/abc.html):
"While seeming counterintuitive at first, some limited degree of water absorption is desirable. DOT 3/4/5.1 glycol-based fluids will readily absorb water. The helpful part of this is that every brake system will contain some moisture, which cannot be avoided. Absorbing this moisture, while reducing the fluid’s boiling point and increasing its compressibility, allows the corrosion inhibitors in the better brake fluids to do their job and keep system components fresh. And, just like with antifreeze, these inhibitors are gradually depleted in use, which is the primary reason brake fluid needs to be changed periodically." [Bold added for emphasis]

When I said: "The DOT 4 brake fluid absorbs water much more than DOT 3", I was being simplistic for readability. DOT 4 is somewhat less hygroscopic than DOT 3 (absorbs less water), but then it breaks down faster when it absorbs moisture. Review this article by StopTech (http://www.stoptech.com/technical-su...rs/brake-fluid)
"A seldom talked about characteristic is that because of this chemistry, the DOT 4 fluid will have a more stable and higher boiling point during the early portion of its life, but ironically once the fluid does actually begin to absorb water its boiling point will typically fall off more rapidly than a typical DOT 3."

[bluptgm3]

For several thousand miles I often had to go to second before engaging first, and reverse has always been problematic when transmission is cold when stopped.


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[Bilito]

The #1 most likely culprit bar none is the rubber clutch line. It is a fine idea to replace the transmission fluit as well, but replacing the rubber clutch line will most likely solve the problem. Here is a thread on the subject:

https://www.bimmerforums.com/forum/s...1#post27938021

I am looking under that hood for either a rubber or stainless clutch line and the clutch reservoir, and can locate none of the above. I am assuming the reservoir is near the brake reservoir somewhere, or do they both share the same reservoir??

[Vintage42]

I am looking under that hood for either a rubber or stainless clutch line and the clutch reservoir, and can locate none of the above. I am assuming the reservoir is near the brake reservoir somewhere, or do they both share the same reservoir??

The reservoir is shared. The clutch line is metal to under the car, where it transitions to rubber going into the slave cylinder. This post shows a new SS line.
https://www.bimmerfest.com/forums/sh...3&postcount=12

[zellamay]

I am looking under that hood for either a rubber or stainless clutch line and the clutch reservoir, and can locate none of the above. I am assuming the reservoir is near the brake reservoir somewhere, or do they both share the same reservoir??

Same reservoir. Easier to see from the bottom.

[Mr Bingley]

Follow the links provided--it will all make sense.

[Bilito]

They share the reservoir great and since all I see is metal lines and you say the rubber part begins under the car, Now I have a place to look tomorrow