Tim Baxter
Tim Baxter Online Editor
9/9/08 2:14 p.m.

My father-in-law has an old Saab 900. Think it's an 88. Great car, in spite of 300,000 miles, but since he got it the thing appears to have become magnetic. People keep hitting him. Then the hail came.

Anyways, he's got his eye on a '91 900 Turbo. It looks promising, but it's got an automatic.

So.. are those old Saab slushboxes problematic?

And if he wants to swap out the manual from his '88, are there any tricks or gotchas he'll have to watch out for?

Travis_K Reader
9/9/08 2:19 p.m.

All I know is that almost every one on craigslist says the tranny is bad. But then 3/4 of the 5 speed ones do too, so who knows.

914Driver HalfDork
9/9/08 2:41 p.m.

The tranny has always been the weak link in the chain for those. Automatics draw more depth, if you lower the car or run weaker shocks than a stick car, things will hit sooner. I'm told pre-1992s are the ones to have. GM got in there in the late 80s and by '93 a lot of problems showed up where there weren't any before. Brakes come to mind.


procainestart HalfDork
9/9/08 3:28 p.m.

The autos are junk -- Borg Warner three-speeds that are commonly swapped out for manuals. Bad mileage, slow, heavy, high-revving on the highway, ick.

The swap is pretty straightforward; there is a PDF with good instructions at Saabnet; however, you may have to hunt around the site a bit -- usability isn't the greatest. You MUST install the oil pick-up from the manual transmission, which is a different length than the auto's. Unless the motor's been out recently, it's probably not a bad idea to do the front seal (firewall side) as well as oil pump seal. Alternator bushings (NO polyurethane, just rubber) are easy to do at this time, as is the steering rack if the '91's happens to have "morning sickness." Water pump is easy then, and, especially, the exhaust manifold gasket, too. (Hand-snug the bolts with a short wrench, don't use the torque spec, as aftermarket studs can snap.)

Note: ASSuming your FiL's 900 isn't a Turbo: you'll want to get a 7-piece Turbo clutch kit for a pre-90 900 Turbo, NOT for a '91 Turbo. Saab changed to a different clutch for Turbos in '90 and the later pressure plate will NOT fit the '88 flywheel that you already have on hand. (The earlier Turbo clutch parts are cheaper, btw, and there is no advantage to using the later Turbo clutch -- Saab only did it to save money: the 900 and 9000 clutches were the same that year.)

When you do the swap, it's a good idea to fit a new rear main seal (front of the engine behind flywheel). Make your own seal driver with a piece of plastic plumbing from Home Depot (bring the seal with you to find the right size) Search "homemade seal driver" or "homemade rear seal tool" on Saabnet. I have found a 5-gallon bucket handle to work best for the "clutch tool" you'll need to remove the clutch.

I don't know if you can use the existing console between the seats. If not, then note that the console between the seats in the '88 is different than the '91 -- Saab was by then fitting 9000 seats, which are wider so the console was narrowed. That said, if your FiL's '88 has passive seatbelts then the seats will fit in the '91 (along with the '88 console), as they have the same bolt pattern.

You might run into issues with the plumbing to the turbo. The hard water line to the turbo is different between manuals and autos. Unfortunately, the hard water line does not have a part number stamped on it and I'd be stunned if the lines are still available so you may need to make a trip to a junkyard.

www.eEuroparts.com is the cheapest place for Saab parts.

C900 transmissions will last longer if you change their oil annually. Redline MTL or MTF (can't recall the acronym) works well unless you're in a really hot climate or drive really hard, in which case it's a bit thin.

Feel free to email me with any questions. While I haven't done the swap, for better or worse, I've had my hands in a good number of c900s (did a clutch two weeks ago) and currently own two c900s and ran one in the Alcan 5000 in Feb:

Tim Baxter
Tim Baxter Online Editor
9/9/08 3:31 p.m.

Good info. Thanks!

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