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Auto tranny in 9000s are not reliable?

im looking for a old saab

1995 9000CD auto is my target has done 175000km

any experience??:lol:
 

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Depends. There is nothing inherently bad about the ZF 4 speed in the SAAB 9000. It was used in a few other European cars of the time. ZF makes excellent transmissions. However, if maintenance was neglected or the transmission abused then it is troublesome.

As for all used cars, check the maintenance records if they are available.
 

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The earlier versions of this ZF box had some reliability issues and this is probably where the 4hp18 got it's bad reputation, but the later versions (1994 and up) were much improved. As mentioned above the key issue is maintenance. A well maintained post 94 automatic is very reliable and capable of very high milage provided they had regular oil changes. Mine has done over 370 000 km now behind a severely tuned engine and is still shifting perfectly.

However if maintenance was neglected they can fail well before 200 000 km. If there is no maintenance record be careful. Pull the dipstick and wipe it off on a clean piece of white paper. Clear red is perfect, a little dark is ok but change it soon, dark brown or black deposits or burned smell means walk away. Also go for a long test drive as sticky valves often start playing up only after the trannie is warm. Pay special attention to the 3-4 and 4-3 shifts under various load conditions. If the oil looks ok and the transmission shifts smooth, go for it.
 

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Common 4hp18 problem

The 4hp18 is a good piece of machinery. But it has a bad rep due to a simple problem that frequently gets the entire transmission junked. Sadly in some cases the entire vehicle is junked because of the high cost of a new/reman transmission.

The problem is worn governor seals. This condition manifests itself in many ways, most often shuddering after slow down. But also it will cause extreme over revving, high shift points, total loss of reverse (usually temporary) and difficulty shifting into 3rd and 4th.

Nowadays, many shops are reluctant to open a transmission at all and will immediately advise a replacement. So for the lack of 2 little rubber o-rings, a perfectly good tranny gets crushed.

The seals in question are extremely easy to change and the cost is minimal. The procedure is outlined in this forum somewhere.

Also, if time is short and the repair must wait, the transmission can be sort of shifted manually. Just start in 1st, and using your tach or ears for reference, slip the selector up to the next range at the appropriate speed. It will not slip in this mode.
 

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besides the governor seals there are unfortunately 2 more common failure modes, the good news is that they are all easy fixable:

- sticky valve in the valve body, caused by dirty oil/lack of maintenance. Mostly the 3-4 or 4-3 traction valve will lock up, causing erratic or no shifting into 4th and a complete loss of forward drive if the car slows down coming from 4th gear. Also can cause whining noises. Sometimes temporary cures itself when the trannie cools down.

- broken or worn springs in the valve body, causing all kinds of issues. Mostly on the older trannies, the newer ones have upgraded parts.

Yes it's a shame so many good 9000's are scrapped because of small automatic transmission issues. All of the typical 4hp18 problem are easy fixable on your driveway by anyone who can hold a spanner. No need to remove the transmission from the car, no need for special tools, costs of the parts are next to nothing. The problem is that virtually no shop will perform such partial repairs so you have to do it yourself :evil:
 

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The problem is worn governor seals. This condition manifests itself in many ways, most often shuddering after slow down. But also it will cause extreme over revving, high shift points, total loss of reverse (usually temporary) and difficulty shifting into 3rd and 4th.
Where are these 2 O-rings located ?

Does the worn O-rings also cause very early shift ups and late shift downs causing shuddering when accelerating from low speed, and during slow down (assuming the kickdown cable is properly adjusted).

I occasionally experience loss of reverse. By moving the shifter continuously between "D" and "R", reverse functions again. The temporary loss occurs at 1 out of every 4 shifts into reverse.
 

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Those (the ones you describe) are the textbook symptoms of hardened/cracked governor interstage seals.

Also there is a spring -Accumulator spring 0732-042-227 is usually bad one when you have slow 4-3 downshifts and D-1 engagements.

The governor seals are wicked easy. Dump the ATF. Remove the LH -Tire and inner fender. There will be a cover plate staring right at you...

You know what - here are some good links that explain the process much better than I can:

Alfa Romeo used the 4hp18 for some models. A discussion about both the governor seals and the accumulator springs:

http://www.alfafaq.com/id16.html

and a nice step by step

http://www.alfabb.com/bb/forums/164-168-1991-1995/15244-alfa-164-zf-4hp18-automatic-valve-body.html


This guy has a great write-up (with photos) on gov seal renewal:

http://www.saablink.net/forum/general-9000-posts-information/51033.htm


Townsend's link for the job:

http://townsendimports.com/Web/transmission_folder/9kgovsealsb.htm


Alldata's R&R procedure:

Removal
1. Start by removing the lefthand front wheel and the front half of the fender liner.
2. Undo the 13 screws (Screw size = TORX TX7).
3. Lift off the intermediate gear cover and then remove the gasket.



4. Remove the screw on the pinion shaft:
    • From Transmission No. 14498, the screw is secured with Loctite.
    • When removing, the screw must be heated to 120°C (248°F).
    • From transmission No. 20426 in model year 1998, the screw is secured with with a bendable flange.
    • Bend up the flange and undo the screw on the pinion shaft.
    • On all transmissions, the parking pawl must be engaged.
    • Socket = 36 mm.
5. Remove the gear from the pinion shaft.
6. Heat using a hot air gun and remove the bearing race.



7. Lift out the governor together with the governor housing. NOTE:
    • When cleaning the governor, only undo the retaining screws so that the governor can be removed.
    • Check that the governor valve moves freely.
    • If the valve is stuck, dismantle the governor and thoroughly clean the parts.
    • Lubricate the parts using automatic transmission fluid before assembly.
    • Install the governor in its housing.
    • se a TORX TX27 wrench.
    • Tighten to 10 Nm (7.3 ft. lbs.) .
Installation
1. Apply Vaseline to the seals and carefully install the complete governor. NOTE: When the governor is correctly installed, the governor hub should be level with the splines on the pinion shaft.
2. Heat the housing with a suitable hot air gun for 3-5 min., to about 70°C , and install the bearing race.
3. Install the spacer sleeve and washer to the pinion shaft and install the gear.



4. Insert the parking pawl and tighten screw.
    • A flange screw has been introduced.
    • When installing, any screw without a flange should be replaced with the newer flange screw.
    • There is a long and a short version of this screw.
    • Tightening torque, 24 mm long screw: 150 Nm (110 ft. lbs.) .
    • Tightening torque, 70 mm long screw: 170 Nm (124.7 ft. lbs.) .
5. Apply a thin coat of Vaseline to the gasket and install it.
6. Install the intermediate gear cover with the 13 screws (screw size = TORX TX27). Tightening torque: 10 Nm (7.3 ft. lbs.)
7. Install fender liner and wheel.



Back to me talking again:

Although it is not a difficult job, it is almost a neccesity to have an impact wrench (to break that big bolt free) and some heat to aid in bearing R&R.


I'm hoping that Mr. 90000006 jumps in and helps - he's probably forgotten more about this subject than I ever knew.
 

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Thanks a million for that information :)

From the Alfafaq link, my problem may indeed be the governor seals :
quote :
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
"
unquote


A couple of questions :
1. From the Saablink write up, after the pinion gear is removed (assuming together with the governor and valve housing), the governor seals will be visible. The Alldata procedure mentions removing the bearing race with a hot air gun, then lifting out the governor with the governor housing. The Townsend site mentions "when removing the governor valve bodies, do not remove the governor housing". The Saablink site however shows a pic (below) of the governor alone, separated from the valve housing. What exactly is required once the pinion gear is removed ?





2. Which bearing race is the Alldata procedure referring to ? (I can't locate the bearing race in the EPC diagram, only the roller bearing is shown, does the bearing race sit inside the governor ?) Is it necessary to remove this bearing race, if the intention is only to replace the seals, and not to dismantle the governor valve ?

3. The Alldata procedure mentions that the parking pawl must be engaged, how do I engage this ?

4. Is it safe to use an air impact wrench to break the 36 mm pinion nut free ? The Townsend site mentions not to use air tools.

Thanks once again :)

 

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Some points of attention and answers to your questions:

Before you start, get 5 L of ATF dexron II, a new gasket for the side cover, a set of new rings for the governor (2 rubber, one metal) and a new bolt. Best to order those at a transmission repair shop. The bolt comes in 2 lengths, 24 or 70 mm. Based on the transmission number a good repair shop should be able to get you the correct one.

- keep the internals of the box as clean as possible!
- putting the box in P will lock the axles so you can undo the bolt that holds the gear.
- An impact wrench for the bolt is not necessary. The socket size is 36 mm, make sure you have one that will grip a bolt with a very flat head
- after removing the bolt you can take off the gear by hand. The inner bearing race will come out with the gear.
- behind the gear are one or 2 washers and a sleeve/bush, take them out and make sure you don't loose them!
- the outer bearing race is pressed into the gearbox housing but the fit is not very tight. Use a large screwdriver and some leverage and out it pops. Make sure it comes out straight. I never applied heat but I guess it doesn't hurt to do so.
- now you're looking straight at the governor. Just pull it out by hand and you can see the rings. In your case I'll put my money on the one in the middle, probably broken. If so make sure to collect all the pieces
- clean the surfaces on the side cover, makes sure you remove all of the old gasket.
- replace the rings and put back the governor. Take great care in not damaging the rings while doing so, apply vaseline or clean ATF. It should slide in without much force.
- depending on how tight the fit of the outer bearing race is, it can be necessary to heat up the gear box casing (not the bearing!) before you press it back in. Use a hot air gun/paint stripper
- make sure you put back the washers and sleeve behind the gear in exactly the way they came out as those are used to set the bearing play on the axle
-torque down the new bolt to 150 nm for the 24 mm or 170 nm for the 70 mm. Lock the bolt with a small hammer and chisel or so, just gentle, don't hammer the * out of it
- while you're there, remove and clean the filter, magnet and put in fresh atf

you won't recognize your box back after this exercise. Happy driving!
 

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I find that an impact tool makes the job much easier and does not cause any damage. Because I do the governor with just that wheel jacked up there is limited space for a breaker bar.

Also the ears on that washer under the bolt head (the ones that hold it in place) are hard to flatten enough to free the flats and let the bolt head turn. An impact socket runs them right over. When those tabs lay down the interference fit in the threads breaks free and the bolts will spin out with your finger tips. Maybe 2-3 knocks of the impact is all it takes. The caveat against using air tools is included for the glued in type of bolt which needs to be wrenched all the way out sometimes. Repeated shocks to the gearing are the concern. It isn't really an issue with the lock washer style.

BTW - I wish you luck locating those seals. The 4hp18 transmission is out of production and with fewer and fewer cars running them, not many places stock parts for them. You may have to buy an entire soft parts kit. Not too bad though - maybe $100. There is a Transtar facility close by and not even they stock just the governor seals.

I have been using off the shelf square o-rings from a local hydraulic supply house. Just bring in your old ones and they will measure and substitute. The metal ring is almost indestructible - don't even take it out of it's slot.

Your questions:

-The bearing race (outer) is lightly pressed into the tranny casing. When you see it you'll know it. That is why I use a propane torch with a mild flame (the "heat" I mentioned). It makes pulling and replacing the outer race a breeze. Just do not let the flame stop in any one place too long. Also heat as much of the surrounding casing as possible - you can't just heat the bore where the race sits. Bring everything up to temp slowly.

- If you have your gear selector in the "P" position, the parking pawl is engaged. And you will have it in park because that will hold the entire rotaing element still while you back the pinion bolt out.

-As regards your first question - after the bolt, washer, shim(s) and bearing cage the governor is gonna come out in one piece. I never understood what they were talking about either.

I have a harddisk around some place that has tons of info on this subject. I will try to find that folder.

But don't worry, it's not that bad of a job.

-
 

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Had some time today to work on the 9000, and decided to have a look at the governor seals. Sure enough, the middle square o-ring is broken and fell off in 2 separate pieces (pics below).





I followed the procedure in chengny's and 90000006's posts above. Removing the governor was a breeze and far easier than I had expected. Here are some photos of the removal sequence.

A pic with the end cover removed. I noticed that my trans mount is shot.



Removed the 36 mm bolt with an impact socket and it came off fairly easily after 2 to 3 knocks.



View of the governor with the gear removed. Is it important to reinstall the governor exactly in this position ?



View behind the gear and the bearing outer race. In my case, the bearing outer race didn't require heat to come off, and just slid off with finger pressure.







I'll search for off the shelf square o-rings next week, the inner diameter measures up at 51 mm, 2.5 mm width and 2.5 mm height.

Can't wait to get the car back on the road.
 

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Great pictures there, looking forward to its resolution, not as much as you though granted!! lol

Seen so many things about the governer, but in relation to the box what do they actually do?
 

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Great work and very clear pictures ;ol;

Must be nice to find something broken, good feeling when you are on the right track to fixing your problem :D

For the o-ring best go to a specialist who overhauls transmissions and get original ZF parts, it's not just the dimensions that count but the right material is also important as the governor is spinning constantly. The Saab dealer can order them as well, although the price will probably be slightly different :roll:

The governor can be put back in any position so no worries there.

Good luck and keep us posted!
 

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+1 thanks for the pics & info - I`m on 230,000 miles on the original box & try to change fluid sooner than recommended just to keep everything happy.
Still shifts as perfectly as in `97.
Must admit the guts of an auto box inspire fear in me as well!
 

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I am absolutely thrilled :)

Fitted the new O-rings today, then took the car for a drive. I had to loosen the kickdown cable, as I had previously tightened it up when the erratic upshifts occured. The gearbox has never felt so good since I aquired the car 2 years ago (the car has been sitting idle for the past 1 year, due to this problem). Gear shifts are absolutely correct now and amazingly smooth.

I was in a hurry to get the car going and did not source for original ZF parts, but decided to get off the shelf rings from an O-ring specialist. Unfortunately, they did not have the correct profile square O-rings, but had X-profile oil resistant rings of the correct dimensions (I'm not sure how to explain it, but if the ring were cut, you would see an X like profile at the cross section). I decided to get them anyway, but cannot recommend them as it was a trial and error solution - in the worst case, I was prepared to disassemble again, as it seemed no more difficult than changing brake pads.

Following are pics of the reassembly.



Comparison between the original and off the shelf O-ring :



With both new O-rings fitted :





More pics to follow.
 

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More pics of the re-assembly.











Decided to replace the worn transmission mount. Fortunately I had a Scantech mounts spare and fitted it :





1993 2.3T Griffin - Dad gave the car a wash and a polish after the test run, looking good with a new lease of life :D



Thank you once again, 90000006 and chengny !!!
 

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;ol; ;ol; ;ol;

Good to see that another one of the best Saab ever built stays on the road. Congratulations with a job well done and happy driving! Let's hope the rings will hold out, if not you know what to do :p

Thanks for posting the pics, hope this will encourage other 9000 drivers to do the same simple repair if their box starts playing up (in stead of scrapping yet another 9000 for a broken o-ring :roll:)
 

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Great write up on the seal replacement job.

;ol; ;ol; ;ol;

Good to see that another one of the best Saab ever built stays on the road. Congratulations with a job well done and happy driving! Let's hope the rings will hold out, if not you know what to do :p

Thanks for posting the pics, hope this will encourage other 9000 drivers to do the same simple repair if their box starts playing up (in stead of scrapping yet another 9000 for a broken o-ring :roll:)
Absolutely agree with the above!!

I have a 97 9000CD (stgI) which shifts too early, it also has very dirty fluid even after a drain and refill, need doing again. After reading this I wonder if I should to this job on the car and replace those seals.

If these cars are being junked because of this then that is a good thing for those in the "know" great cheap cars going and for not much cost to fix them!

My 93 griffin shifts nicely, perhaps a little late but maybe not. 170,000km.

/R
 
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