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Discussion Starter · #1 ·
1992 C900 Sedan, 2.1 NA, 214K. I completely flushed transmission about 1500 miles ago, new filter, new gaskets, ran a total of 12 quarts through to make sure it was clean, name brand Type F fluid. Fluid is at correct level and still looks clean. Now for the last month or so I am having major issues, and today I did not think I was going to make it home from the junkyard 40 miles away. Basically, 2nd gear is on vacation about 75% of the time, and after driving 10-15 minutes or so, it never downshifts out of 3rd, even at redlights. Idles fine and actually has enough power to get moving okay, as long as I am not on an uphill. It's like a C900 with a CVT! If I manually move the selector down into 1 or 2, it will downshift and then upshift very smoothly back into 3rd as I start moving. If I stop and shut the car off (most of the time), when I start out I get 1, 2 and then 3, but then it's always in 3 after that. The upshifts are smooth. But then sometimes after starting out I cannot get out of first at all. It seems like 2nd is not there, and it doesn't want to go from 1 to 3. That is what happened today when I left the junkyard. I was at almost 4K rpm before it went from 1 to 3, and with a slam. There is no consistency on when this happens. Sometimes it's first thing when just starting out; other times it's after I've driven and stopped. I'm fearful that this may be the end of my faithful servant since 2008. I'm not confident going very far from home again as I'm afraid it may implode completely.
 

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That description has the ring of a jammed governor valve which is not too difficult to deal with. You need to get the car on a lift, remove the oil pans and remove and clean the governor and make sure it's sliding OK then check the pipes and circuit to be sure they aren't blocked. Could be other causes but governors did eventually jam on the T37's with lots of miles and cause problems like you are describing. 214K Is pretty long service from a T37.
 

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Discussion Starter · #3 ·
The governor is the one thing I did not touch when I did the previous service. The transmission was shifting good; I just wanted to flush out the old fluid because I didn't know how long it had been in there, at least since 2008 when I got the car.
 

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Some guys theorize that when you flush a unit with many miles on it you make metal particles that are sequestered start to circulate and that jams up all the valves. Unfortunately once that happens it's unlikely that anything short of a very thorough disassembly and cleaning could eliminate all the particles. The theory has some merit but I've also flushed many T37's without any problems developing. As I said, at 214K it was well into it's twilight zone anyway and probably had lots of particles tucked away in the cooler circuit and elsewhere. (I mean like several tablespoons full of fine, hard particles!) I think I overhauled as many high mileage T37's for particle jammed valves as for worn out friction elements, rubber seals, etc. On a positive note, if it was running well until it was flushed it might be a decent candidate for rebuilding?
 

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Power flushing is the Concern. Drain and refills typically don't cause those problems.. Just waste $$ on ATF.
T37 rebuild parts are scarce.
 

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Discussion Starter · #6 ·
I followed the recommended procedure to drain and refill only. Wasn't any kind of power flush. If I remember, only about 3 quarts or less comes out of the pan each time, so I did it 4 or 5 times to make sure all the fluid was clean. Unfortunately, although 100% mechanically and I would drive it anywhere, this car has some significant rust concerns. What do they say, "Rusty But Trusty?" I live in AL but it came from up north (MA). The trunk floor beneath the panel has holes in it; there is visible rust along both sides at the bottom of all four doors, one of the rear shock towers is still intact but very thin (I check it often), and I had one of the brake lines under the carpet rust through last year. Every last thing works on the car, including the A/C and headlight wipers. No warning lights on, and the engine doesn't use or drip a drop of anything. I'm gonna check and clean the governor when I have time (seems easy enough), but I am somewhat doubtful that is the issue.
 

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Another thing you could try is one of those "transission fix in a can" goops. In addition to the "particles that broke free" scenario I've also heard of the "the old fluid was so full of old clutch etc. that is was much thicker than new fluid" explanation. While the "it won't downshift" sounds like a governor to me, the "won't upshift" sounds like insufficient pressure. A viscosity improver might help there.
 

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I had luck once adding a cup of brake fluid to 'clean' it.
A govenor can stick open or closed, you can get at it in the car.
 

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Discussion Starter · #9 ·
OK. Not good. I was gonna go to the store about 5 miles away. Only got about 1/2 mile and it wouldn't shift out of 1st again. But, at about 30 mph I lost all connection to the transmission. It's never done that previously. The engine was just free revving whenever I pushed on the gas like I was in neutral. I coasted to the side of the road to turn around. There was a thunk when I was almost stopped and it was back in 1st, but as soon as I started going again, it did the same thing. I made it back home coasting to a stop and going about 20 mph in 1st, but now definitely not sure how far it will even keep moving.
 

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It's never a good idea to drive a malfunctioning automatic transmission... When things are not working right they can chew themselves up in just a few miles.
 

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Discussion Starter · #11 ·
So I got the governor out thinking that might be the problem. Everything in there is operating room clean, the governor, the whole inside of the tranny, not a trace of dirt, varnish, buildup, anywhere. Here are pictures of the governor. I did not clean it. This is how it came out. I cannot get the two screws broken loose on the cover of the governor to look inside. I did blow air through it and there doesn't appear to be any obstruction anywhere. I had a hell of a time getting the screws holding the governor on loose. The heads pretty much stripped, and I had to use a screwdriver sideways on the end of the slot and hammer trying to get it to start turning. Is there anything else I should lookl for before I put it all back together? Everything looks pretty much brand new.
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Your "clunk and starts working" sounds like a defective "overrunning clutch" (sprag clutch) locking in.
I'm with everybody else, tow it to a trans shop before more damage is done, or give up on it (body wise) and part it out. Continued attempts are more likely to do more harm than solve a problem.
 

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I don't know what I'm talking about, but since you have the pan off I think it wouldn't hurt to check the band adjustment. I don't think that has anything to do with anything, but with limited things to try and a low chance of success, it can't hurt.
 

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The governor doesn't seem stuck.
How far do you want to chase it? Cleaning the valve body and air pressure checks would be next in no-cost stabs at it.
 

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Discussion Starter · #15 ·
This is just last ditch effort to see if there was anything I could do to save it. From looking at it and measuring, it looks like band adjustment has already been done at some point. I will double check. Going to put it back together and hope for the best . . .
 

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Discussion Starter · #16 ·
Cautiously optimistic . . . didn't do anything but remove and inspect the governor and put it all back together. Went for a 22-mile test drive encompassing highway speeds, slower speeds, and a lot of stops and starts. Shifted perfectly the whole time, both up and down and very consistently and smoothly. Never once did anything weird. Did not stick in 3rd when I stopped, hit 1-2-3 every time I started, never missed 2nd or hung up in 1st, and shifts were smooth. Got to get more road time in, but maybe there's a Saab angel looking over me!
 

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Good news! I've had that exact experience more than once on these units (long ago) which is why I suggested checking out the governor. My recollection is that the cure was sometimes permanent but not always. There are a few other things that can shake loose or jam up inside the T37 and cause severe performance issues but looks like you may have lucked on to the culprit first time out. Those screws being over-torqued hints at a possible source for the trouble. Did you notice any loctite on their threads? Curious, did you remove both pans or just the rear pan? A valve like that can also jam up due to a single particle and it may have fallen away in the disassembling before you had a chance to inspect the parts. Anyway, nice work!
 

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Once, I was lucky enough to find a real piece of crud stuck in one.
It is such a satisfying repair, congratulations!
 

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Discussion Starter · #19 ·
No loctite on the threads for the governor, but the screws were ungodly tight. I had both pans off originally about 1500 miles ago when I did a complete fluid swap and filter replacement. Everything is super clean. Thanks for the input.
 

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The oil pick up tube for the pump is above the front pan and those were known to sometimes come loose causing the pump to run dry with resultant complete failure to move. Just file that away in case there is a replay.
 
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