98SL2Mike

95 Sc2, I just installed a 99 Sl2 auto transmission, having been assured (by qualified persons) that it works fine for 95-2002 auto trans to be swapped (dohc to dohc). Changed fluid and filter at the time of the swap, have driven about 5 miles since. Problem is, when it's driving it seems to be fine, but when it upshifts or downshifts, about 90% of the time it involves a bone-jarring thunk. Throttle position doesn't seem to matter. No codes being thrown. I haven't tried the "Wolfman fix" yet, will try that tomorrow, but I'm wondering if it should be done differently since this is a forward gear issue? It doesn't clunk when shifted from Park to Reverse, Park to Drive, drive to reverse, etc, etc, but 1-2, 2-3, 3-4 and vice versa (downshifts). This tranny has about 60,000 miles on it, (120,000 less than the car). Any help would be appreciated.

Thanks in advance,

-Mike

wolfman

Don't know who your "qualified person" was, or that you'll like this answer, but as far as I know the control systems for a 99' autotransaxle are NOT compatatble with a 95' PCM. The 99's do not use a perf/norm switch (among other things) that the 95's do....99's are also controlled by an ODB2 PCM, while 95's are OBD1 (two very different animals) etc...etc...

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monkeyracing

Sounds like it's got waaaay to much line pressure.

jim

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You've got a 10 second car, huh? How fast does it go on the track?

98SL2Mike

I was kind of thinking line pressue as well, but the cause escapes me. I'm by no means a transmission expert, but I'm always willing to try something (provided I don't have to lift that heavy SOB outta there again!). Is there any easy way to clean thevalve bodies on these things?

This is why our 98 is a stick!

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Ssicarman

If you still have the old trans I would try swapping the valve bodies (depending on why you replaced the trans of course) to see if this will solve our problems.

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Joeybagodonuts

actually i can confirm for a fact that at least 95-6-7-8-9's are interchangable... ive done it, MANY times....
as far as how the obd1 and 2 is concerned it doesnt matter. just like people swear you cant put a 97 motor in a 95 cause of the ob codes, the sensor HOLES ARE ALL THE SAME, so yes you can use any year motor in any other year, lately ive been seeing more swap info thats pretty accurate on the internet, but still no-ones done every single kind of swap possible )(cept little old me, LOL)
now, if the trannys been sitting any length of time then wolfies fix should cure her right up.
also check the vss fuse as that will skyrocket line pressure, even pros like myself miss that sometimes (yes i put 3 trannys in one of my cars learning the hard way to remeber KISS, keep it simple stupid... LOL)
not sure who told you 95 and others are interchangable, but they are, so your qualified person was indeed correct....

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Cheddar454

how can i make my '95 SL2 have "jaw rattling" shifts? my transmission is sluggish and raising the line pressure is exactly what i want.

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RiceRocket

I was thinking the same thing. I bought some fluid additive. It smoothed out the shifts too much, it doesn't bang the next gear like it used to

There's a fuse you can pull out that will raise line pressure hugely but the tranny won't last too long like that.

Or you can just leave it in perf....

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98SL2Mike

UPDATE: Anyone who wants to swap me trannies in the KC area, let me know. This one sucks.

Okay, so TWICE I tried the idle in reverse for 30 minutes fix, didn't help. Tore the valve body out, inspected probably screwed it up (yes, took it apart & put it back together), nothing. As of now, it's a 99 tranny with a valve body from a 93. It's about to have a 2004 hammer included in the mix. SOME of the shifts have smoothed out (probably at 50%now), where it didn't CLUNK into reverse before, it does now (most of the time). All of the valve actuators are within 1 ohm of each other (the 98 FSM says this is correct). Any more suggestions?

ALSO, this car has another strange issue. It isn't charging the battery. Light is on, but the alternator has been tested good, and the fuseable link between the starter and alternator has been replaced (later found out it was good also). Electrical is NOT my forte'. I'm thinking since have another alternator, I'm going to go ahead and swap it tomorrow, even though the one in it tested good. For now, the brand-new battery is charging.

Thanks again,

-Mike

98SL2Mike

Also, I checked every fuse marked TRS and TCC, but I can't find any labeled VSS. Is it listed under something for more cryptic, or have I already checked it?