Here is text of my tech article from Feb 2006 Alfa Owner. If you have copy of that issue there are some pictures I sent along with article:
Alfa 164 Automatic Transmission Repair 16-01
Replacing bad spring in Accumulator A to cure slow/harsh gear engagement.
By Alfisto Steve AROC 164 Tech Advisor
Well, if you have a 1991-1993 Alfa 164 with a ZF 4HP18Q AUTOMATIC and it works well it is a smooth shifter, but things can go wrong. This article will cover a few and what I and others have found to be possible repair solutions.
I have been a 5-speed fan with my 91 164 base model I have owned since new so I have been late getting into automatic world but I had to help a friend out with his 95LS a couple years ago. Now that model uses a computer controlled version of the ZF, the 4HP18E. More on that model possibly in a later article as tech data hard to find and understand, I now also own a 91 164B with AT that I had to correct a shifting problem listed below.
Anyhow as I had to understand something about my friend’s 95, and also repair a 91 164L automatic unit I had in my spares, I searched the internet and found Eriksson Industries division of Wentworth Engineering, 146 B Elm Street, Old Saybrook, CT. 06475, 800-388-4418 at
Eriksson Industries Usually when I call or email I get Nat Wentworth himself to answer. He is a treasure trove of information and their web site has a three (3) page exploded view of transmission with index numbers. He is very helpful and he suggested I buy a copy of the Saab 9000 service manual Saab order number 361097 on this transmission. He had a new copy of manual in stock. The outer case on Saab ZF transmission is somewhat different but the parts inside are pretty much the same as a 91-93 164 transmission. This Saab shop manual has very good troubleshooting, disassembly, assembly and testing procedures. So armed with this Saab manual, the website with exploded parts views like this
4HP18Q DIAGRAMS and Alfa 164 shop manual section 16 on automatic I tackled the ZF automatic.
The easiest to fix and most common ailments I have come across are these problems:
Transmission slow to go into drive from Park or Reverse and slow 4-3 downshifts. Cause - weak Accumulator D spring.
Transmission with a hard slamming clunk into drive or harsh 4-3 downshifts. Cause - broken Accumulator D spring.
These problems are caused by a $4 spring in Accumulator A which is attached to bottom of valve body (distribution box) in top of transmission. If spring just weak and slightly compressed shifting will be slow but if spring cracked shifting will be slow and engine can race and then you can get that harsh slamming into gear.
Other problems such as erratic shifting/downshifting can be repaired too according to AROC member Lorinda Pate and verified by Mr. Wentworth. So here I quote Nat in his email reply:
“The problem with governor seals breaking is quite common in the
Alfa and Saab 4HP18Q transmission.
Common symptoms: 1. shifting up too soon, or not down shifting
when slowing down. Can shudder or attempt to stall engine when
stopping. 2. Occasionally no reverse engagement. 3. Shifting up and down seemingly at random, while driving at steady speed.
There are three seal rings on the back side of the governor
housing, a metal ring and two rubber rings, the main oil
pressure is supplied to the governor between the metal ring and
the center ring. Regulated governor pressure is supplied to
the valve body between the two rubber rings. When the center
ring breaks there will be cross leakage into the governor
passage and the valve body will interpret this increased
pressure as increased speed, thus shifting too soon or not down
shifting at the correct time. There is a valve which blocks
reverse application when governor pressure is above a certain
point, thus preventing reverse engagement.
There is a spring in the valve body which occasionally breaks,
that will cause harsh engagement into D, and/or a harsh
downshift from 4 to 3. This spring fits into the small housing
on the bottom of the valve body opposite the throttle valve
valve with roller on end).
Nat
Eriksson Industries
1-800-388-4418
Eriksson Industries “
I have not experienced the governor seal problem so have not yet attempted that repair. However, Lorinda Pate has had it done and he submitted a write up about it which has prompted this first article to be written about the spring replacement. Look for another article soon on his repair story on governor seals, but first I will just cover how to change that pesky $4.50 spring for that slow/harsh N-D and 4-3 shifting. I know of 4 to 6 of us who have now fixed our shifting woes by just changing the spring Nat addresses in last his paragraph.
Changing Accumulator A rear spring.
There are two springs in Accumulator A, but Nat says smaller front one never a problem and ZF doesn’t even stock it. If you look in exploded view page 3 on web site
4HP18Q DIAGRAMS you will see spring that goes bad near top of view the spring is index 26.390 (ZF part number 0732-042-227). That is the spring to change, but since I am already going in accumulator housing I also ordered Accumulator D spring index 26.420 (ZF part number 0732-042-197 for about $7.50). Why not have new spring just in case. Suggestion: Print off page 3 from web site.
How to get to valve body
Reference: 1991-93 AR164 shop manual section 16-35/36
1. Set parking brake and put gear selector in low (position 1).
2. Open hood, remove air flow meter/air cleaner box top and bottom, disconnect cruise control actuator and ABS line clamps from lower air cleaner mounting bracket and tie out of way. Remove mounting bracket and lift coolant tank return hose up and tie up with a bungee cord.
3. Using a 1/4:” drive ratchet, extension and 10mm socket locate and remove 4 corner bolts and hold down clamps that secure steel cover to top of transmission and one bolt holding front bracket to cover for thermostatic valve.
4. Carefully remove cover and rubber gasket (reuse gasket).
5. Using a Torx 27 serrated bit in a correct bit socket holder locate and loosen 10 larger headed Torx head bolts around perimeter of valve body. Note: there are 8 long bolts, one a little shorter in left front corner nearest engine and one even shorter one right front corner nearest headlight. Do not mix up. Leave them in valve body once loosened. Caution: If using regular socket to hold bit glue and tape bit securely in socket as you do not want to drop it into transmission.
Now to work on valve body and change Accumulator Spring
References: Saab 9000 AT shop manual page 286 and 164 shop manual pg 16-36
6. Once 10 bolts loose, carefully lift valve body straight up off transmission and put it on a very clean work bench covered with lint free shop towels inside a clean tray if possible.
7. Now go back to transmission and check that gear shifting bell crank did not lift up. Refer 164 manual see section 16-38.
8. Now to change Accumulator Spring you will need to either remove those loose ten (10) Torx 27 bolts and carefully mark remember where two shorter ones go or hold them in place with a square piece of clean stiff material as you turn valve body upside down.
9. Before you remove end cover index 26.440 notice Accumulator A has a small spring loaded passing gear plunger with roller on it sticking out other end. Be sure it is spring loaded and moves against spring. How springy depends on condition of infamous rear spring inside. There are two springs as I mentioned earlier for this plunger. One index 26.340 nearest to roller end not the bad one.
10. Also note that gear selector index 26.376 is next to it in Accumulator D position. THIS PLUNGER must be fully retracted in low gear (position 1) when reinstalling valve body on transmission.
11. With body upside down locate accumulator body end cap index 26.430 and four screws holding it on. Loosen one on Accumulator D end slightly and remove other three.
12. Slowly pivot end cap open on remaining screw as poppet/spring can fly out.
13. Remove poppet/plunger index 26.400/26.396 and then infamous bad boy spring 26.390 (ZF 0732-042-227) in one or two pieces if broken.
14. Replace spring with new one and reinstall poppet correctly.
15. Now rotate cover some more and remove poppet index 26.410 and spring index 26.420. Compare spring height to new spring 0732-042-197, replace if shorter.
16. Reinstall poppet, and while pushing in both poppet/springs assemblies close cover install screws and torque to 6Nm (4 lb ft).
17. Check roller plunger for spring tension and push shifter plunger all the way into valve body.
18. Turn valve body back over and be sure ten bolts in proper positions as defined in Step 5.
19. Ensure shifter plunger still fully retracted in valve body and gear selector in car still in position 1.
20. Set valve body back on transmission engaging gear selector into selector bell crank. Tighten 10 Torx bolts to 10 Nm (5.8 ft lb).
21. Reinstall top cover and gasket, fixing clamps and 5 bolts, torque lightly to 6 Nm (4.4 ft lb).
22. Reinstall air flow meter/air cleaner top temporarily, hook up electrical connector to air flow meter and put car in park.
23. Start up and check that gear selector engaged in shifter linkage. If transmission will engage into Drive, Neutral, Reverse properly, finish reinstalling air cleaner and cruise control parts and take a test drive.
24. If transmission will not engage gears shifting plunger did not engage in shifter bell crank and you will have to remove valve body and set up plunger and shifter again to position 1 and plunger fully retracted.
If you have governor seal problems as described by Nat or Lorinda Pate refer to Alfa 164 shop manual section 16 pages 39-41 steps 1 through 17 and/or appropriate sections of Saab manual and order parts and repair info as needed from Eriksson Industries.
Here is Lorinda’s email:
> From: Lorinda Pate
> Date: Thu Nov 3, 2005 11:24:52 PM America/Los_Angeles
> To: editor@aroc-usa.org
> Subject: Alfa 164 bulletin for inclusion in your publication
>
> Dear Editor,
> I hope you will find this item to be of interest to owners and repair
> facilities who deal with Alfa 164s. Please include it in your Alfa
> Romeo publications and websites.
>
>
> Read This Before You Rebuild or Replace Your 4HP-18 ZF Automatic
> Transmission:
> If your 164's automatic transmission exhibits all or some of the
> following symptoms, there may be an inexpensive alternative to
> removal/rebuild/replacement of the unit. This simple repair eliminated
> a problem that several shops thought could only be solved by a > rebuild.
>
> Here is what was done:
> Replaced 3 seal rings on the governor housing, and replaced an
> accumulator valve spring in the valve body that was cracked. Flushed
> all the ATF from the system, replaced it with Dextron III and added
> Red Lube Guard. All of this took approximately 8 hours, and total cost
> was $667.92.
>
> Symptoms:
>
> 1) Changes up early and haphazardly, sometimes changing down almost
> immediately.
>
> 2) Sometimes won't go into reverse without shifting through all the
> gears "1", up to "park" and back down several times.
>
> 3) Overdrive shifts in and out early. At idle, car sometimes shudders
> and surges. It works fine when shifted manually.
>
> 4) (This developed later, and led me to call ZF for a new tranny.)
> When shifting into a forward gear, or reverse, from "park", a clunk is
> heard. Also, when the car downshifts from overdrive into the lower
> gear, again, a clunk.
>
> Who to call:
>
> I called Nat Wentworth at Erickson Industries (800-388-4418), the ZF
> Distributor in Connecticut, as referred from the ZF Headquarters
> (847-478-6868 x6761) in Illinois.
> My intent was to purchase a factory-refurbished 4HP-18 ZF transmission
> to replace mine.
>
> Nat asked what my symptoms were, and told me that with about $100
> worth of parts and a good transmission shop, the problems could be
> repaired without removing the unit from the car. Nat sent the parts,
> gave detailed verbal instructions and faxed tech sheets to Rusty at
> Alliance Transmissions in San Marcos, CA.
> (Do-it-yourselfers, please don't call Rusty for advice, call Nat or
> his staff.)
>
> This repair solved a problem that had been ongoing since the car was 3
> years old. The previous owner drove it sparingly, shifting
> manually, and changed the ATF every 20K miles. My 164L now has 106K
> miles on the odometer and the gear changes are imperceptible. What a
> fun car to drive! Absolutely amazing difference!!
>
> If you are having similar problems, first call Nat at Erickson, then
> find yourself an honest transmission shop that isn't adverse to taking
> advice. Even Alliance didn't believe this would solve the problem
> until Nat talked to them, and several mechanics treated me like I was
> certifiably insane for insisting on finding an alternative to a
> rebuild. Nat is a Godsend!
>
> Lorinda Pate, Carlsbad, CA
> November 2, 2005
Alfa 164 Automatic Trasmission Repair 16.01
Quote:
