Saturday, November 8, 2014


 I have reconditioned a TON of Saab 95/96/97 transmissions over the years--this one is number 519--and have seen a lot of different combinations of CRAP oils that owners or mechanics have put in them.  This one was new to me and was probably the nastiest GLOP I have ever found. It was about 1/8" thick and was total SLIME, and completely unidentifiable in nature. It looks like RUST but none of the trans parts were rusty. It WAS sticky, so I suspect SOME of the YUK was STP, which is a complete NO NO for these units. 
 The GOO was all throughout the transmission--thick, ugly, yet more or less pliable, sort of like molasses at zero degrees F. I completely dismantled the transmission and sent the case and covers to my machine shop to be run through the hot tank. No way was I going to spend 2 or 3 hours trying to clean the CRAP out! Clearly the last owner had no clue about what transmission gear oil to use in a Saab transmission.
 There is a VERY good reason to use the correct gear oil[s] in a Saab transmission. The exploded view above shows a section of the gears, bearings, etc that fit on the MAIN SHAFT of the Saab 95/96/97 transmission. There are four needle bearings on this shaft--see numbers 30 in the drawing. The numbers 31 indicate a slightly different size needle bearing used inside 4th gear [No. 33] on later transmissions. Gear oils heavier than SAE 75 GL5 or SAE 80 GL5 simply will NOT lubricate these needle bearings. Similarly you must NEVER use a HYPOID differential grease which is available in SAE 90 or SAE 140 viscosity, for the same reason.
 Above is a typical differential assembly. Items numbered 6 and 11 are the heavy duty differential carrier bearings. Items 16 and 20 are the pinon shaft bearings. These are large and open, so it is easy for the heavier greases to keep them lubricated. It should be plain to you that this is not the case with the needle bearings in the Saab transmissions.  DO use the correct gear oils. I have used AMSOIL synthetic gear oils for 40 years or so and have never had ANY problems with them--they are the kindest thing you can do to your Saab transmission.  It is also a very good idea to get off your duff and check the oil level in them about once a month. [I offer a dip stick OR an oil check petcock  for this purpose. Either will simplify checking the oil level and make it quicker, easier and less messy than unscrewing the check plug to see if oil will run out on floor].
Here are two of the transmission case pieces--post hot tank--ready for reassembly.
I STILL don't know what that CRAP was in this particular transmission....

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