Dokuji

93 sc400

Ok guys I just bought the vehicle a few days ago and am finding out all its little problems. Of course it didn’t do this to me when I test drove it.

When engaging into drive or reverse, especially when cold, there is a very rough jerk/clunk. mostly a jerk. I'd change the thread title but I can't now. Shifts nicely while driving, however, EXCEPT when downshifting into low gear (I can only assume gear two based on the speed but it being an auto I have no idea. Maybe 1 would make more sense given the issue coming from park into gear huh? Deduction Watson).. however both issues seem to be lessened based on the operating temperature of the tranny. Better when warm.


i just checked the tranny dipstick, hoping to find fluid low and dark but it was at full when hot and the color is surprisingly pink still:


obviously it is a little burnt but not as bad as I was hoping. I will still drain and fill it soon for good measure, as I’d like it to be bright red, but this leads me to believe I have a worse issue.

Would the differential have anything to do with this? (I don’t think so) I will check diff oil soon and make sure to top it off as well.
Possible Driveshaft issue?


Any ideas??? Please don’t just say “need new tranny”

would this level of fluid breakdown cause that kind of issue? I don’t really understand the inner workings of a transmission so anyone who can help me
understand what I’m dealing with in some more technical detail would be much appreciated. Thanks guys.

JoeBlob

What RPM do you idle at? I've noticed mine idles high @1000-1200rpm and it catches drive and reverse pretty hard. I assume it is mostly a mix of that high idle speed when a gear engages coupled with a completely wrecked transmission (and probably motor) mount letting it jerk a bit before catching and banging.

Lexyaaaas

iTrader: (2)

Are you sure the clunk is the transmission? More likely its the rear end

Dokuji

sorry i forgot about this thread. XD

My idle is safe and sound at around 6-700 so I don't think it's that. Would weak mounts really cause that?

also you should check your timing to make sure its correct and then adjust your throttle tension. over 1k is too high.

Dokuji

Like I said, its more of a jerk than a clunk. wish I could change the thread title.

I really don't think its differential related because it doesn't really do it in motion, other than occasionally coming to a stop.

I have been finishing suspension and brake work recently,
so sometime by next weekend I'm gonna make sure the diff is nice and filled with fluid, just to be sure, and I'll update you all.

thanks for the replies.

Lexyaaaas

iTrader: (2)

Get under the car and have somebody shift into drive or reverse.
Watch the diff or trans and see if it jerks around. Easiest way to see where the noise is coming from

Lexyaaaas

iTrader: (2)

Or its probably safer to just lay on the ground next to the car and look under it

ObSCessed

your problem is your kickdown cable which controls line pressure to the tranny, it can be adjusted to get harder or softer shifts. Yours may be broken and have too much slack , causing the banging into gear when cold and down shifting to a stop. I had the same problem,mine had developed too much slack and got loose, causing some erratic shifts and the same harsh bang into gear. Cable cost 70$ or so from lexuspartsnow.com.