ZF Electric Shift solenoids

dtfeld

Water Contrails
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Jun 5, 2016
5,518
Milton, GA
Boat Info
410 Sundancer
2001
12" Axiom and 9" Axiom+ MFD
Engines
Cat 3126 V-Drives
I've been fighting an intermittent issue in my startboard engine/transmission since I've owned the boat. Occasionally and randomly, the starboard side transmission seems to "drop out" momentarily and then re-engage at cruise. Its so quick, its hard to "see" on the dash gauges.

Since it could only be an electrical or hydraulic issue, I planned to service both systems extensively in the off season. In doing so I think I have found my problem.

20181116_153535.jpg



Some POS, er uh PO (or unscrupulous mechanic) replaced the shift solenoids with a generic ZF automatic transmission solenoid. Wrong pressure rating and wrong voltage to boot. Can't imagine why. These are $35 on ebay, the marine transmission versions are $350/ea.

I do agree that a 10X markup is highway robbery.
 
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Interesting discovery. I'm glad you found it quick. That $35 part can easily do a catastrophic damage to a transmission by disengaging and reengaging at high RPMs. I wouldn't take this malfunction lightly.
 
Curious.....How do you know it was the PO and not someone he hired to fix the problem? Perhaps he didn't know of the change....

Further, I'm surprised this item would fail...And, lastly, $350? WTF...

Regardless of who, somebody was taking shortcuts. Not something many surveys would find either. But time to put on the big boy pants and get it done right. I'm relieved that I think I found the problem, but kinda pissed too. Not what I wanted for Christmas.

Reading up on these, seems ZF did have some problems with these solenoids. If left too long, ruined transmissions on very expensive Audi's, and BMW's.

I'm not sure why the price tag other than it has "marine" in it. Better be stainless and gold plated contacts!
 
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I understand...Just seemed you were throwing the PO under the bus when he might have not even known of the issue....Perhaps he did....

Hope you can find a cheaper source...good luck!

I think I just need to bite the bullet. My biggest concern is forward gear, these CAT's put out a lot of torque once those turbos kick in.

I'm going to purchase 2, install on both forward gears immediately. Reverse isnt much of an issue, but will need to be done before next season starts. I found them at the discounted price of $320 so far. I guess it beats a new tranny.

I have new switches for the shift levers and changing the ATF/filters, so I should be good to go.
 
I think I just need to bite the bullet. My biggest concern is forward gear, these CAT's put out a lot of torque once those turbos kick in.

I'm going to purchase 2, install on both forward gears immediately. Reverse isnt much of an issue, but will need to be done before next season starts. I found them at the discounted price of $320 so far. I guess it beats a new tranny.

I have new switches for the shift levers and changing the ATF/filters, so I should be good to go.

Just wondering how you made out with these solenoids?
 
I purchased 2 from Transmission Marine out of Ft Lauderdale. $285 each. They are for the forward gears. According to the tech I spoke to, these are "pressure regulating" solenoids as opposed to On/Off, so thats why they are expensive. They take just a little more time to get full presure, and are a little easier on the transmission allegedly.

I'm going to drain the ATF out and do a number of maintenance items at once, including new filters/orings, add pressure and temp senders in addition to the new solenoids. I'll redo the reverse solenoids later in the spring.

In addition, I have also purchased all new micro switches for the gear shifters and intend to make sure all wires/connections are tight and corrosion free.

I'm hoping that solves any transmission issues for a while.

I should be able to get at it after Christmas
 
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Update:

Replacing the solenoids was an easy 10 minute job per side. 1 screw to remove a retaining clip and they pop out.

2018-12-19 09.51.42.jpg


The micro switches that I purchased were an exact fit, and it was a couple hour job to disassemble the shift lever mechanism and replace the 4 Fwd/Rev switches and the 2 neutral safety switches, and crimp everything into the wiring harness.

2018-12-18 16.17.53.jpg


The next issue is the replace the connectors on the solenoids as they have some corrosion and to tighten these up as they are currently a little loose and zip tied in place. These connectors are Amp TE Faston connectors. The housing is part # 928673-1. Unfortunately I had to get AMP to speak to an Engineer in Germany for specify the correct "Recepticle". I figure $10 for housing/connectrs to complete a electrical side rebuild. I'll post part numbers once I hear back from Germany.

2018-12-19 09.51.18.jpg
 
If you haven't yet changed the fluid I would suggest you take a sample and have an analysis done, just to prove no significant wear metal constituencies show up.
 
Hey Dave, I meant to mention this when I commented on the high quality of your work in one of your other threads but forgot.
It looks like you are using good crimp connectors that are heat shrink with epoxy inside but haven't seen any of them heated. Is this something that you are doing later and just not pictured?
 
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Hey Dave, I meant to mention this when I commented on the high quality of your work in one of your other threads but forgot.
It looks like you are using good crimp connectors that are heat shrink with epoxy inside but haven't seen any of them heated. Is this something that you are doing later and just not pictured?

Yes.. I shrink em once everything is tight and about to button up...I take pics as I'm working.
 
If you haven't yet changed the fluid I would suggest you take a sample and have an analysis done, just to prove no significant wear metal constituencies show up.

Funny you should mention this...changing transmission fluid today. I use CAT SOS. Just dropped them in the mail.
 
I purchased 2 from Transmission Marine out of Ft Lauderdale. $285 each. They are for the forward gears. According to the tech I spoke to, these are "pressure regulating" solenoids as opposed to On/Off, so thats why they are expensive. They take just a little more time to get full presure, and are a little easier on the transmission allegedly.

I'm going to drain the ATF out and do a number of maintenance items at once, including new filters/orings, add pressure and temp senders in addition to the new solenoids. I'll redo the reverse solenoids later in the spring.

In addition, I have also purchased all new micro switches for the gear shifters and intend to make sure all wires/connections are tight and corrosion free.

I'm hoping that solves any transmission issues for a while.

I should be able to get at it after Christmas
"pressure regulating"?? Only two wires so they are either open or closed.... Me thinks that "tech" was pulling your money chain....
And FYI with the mechanical shifter it's either pressurized to the clutch pack or vented...
 
"pressure regulating"?? Only two wires so they are either open or closed.... Me thinks that "tech" was pulling your money chain....
And FYI with the mechanical shifter it's either pressurized to the clutch pack or vented...

You may be correct, but the part is $300 and that is what ZF specified. A new transmission is $7500 plus hauling and install. Like I said, Im just going to bite the bullet on this one...

I think there's a Billy Joel song that goes...

So I've learned to dance with a hand in my pants
I let 'em rub my neck and I write 'em a check
 

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