Transmission Jerk, Surge, Clunk shifting to Reverse and Drive
 

On my 1995 SC400 the automatic transmission makes a loud clunk/clank when shifting into Reverse and then into Drive. But if I go from Reverse or Drive to Park real slow it doesn't do it when I shift into reverse. When doing it slowly, I can feel a bit of resistance when the shifter goes from Reverse to Park and it sounds and feels as if though something is engaging. When I do it faster or normal speed I don't hear or feel the engaging. I am not real familiar with the internals of a transmission but it is as if though something is worn or maybe the fluid is worn. I checked the fluid and it is pretty red and not very dark colored. I don't think it is a bad transmission mount. I have searched and the only thing I can think is that maybe it is the shift solenoids?

I read where bad rear upper control arm bushings can cause a jerk/clunk/clank but I don't think this is what is going on since I can alleviate it by shifting slowly into Park.

I thought I would post and get some feedback before I go trying to replace those solenoids.

Thanks in advance for any insight/input.

I have this problem on both my SC 400's...

On my 1992 SC going from Park to Drive was a loud Clank, and especially bad if not warmed up long enough.

On my 1996 SC going from Park to Drive is perfect, but going from Reverse to Drive I get the clank.....

I thought Transmission Mount...but I'm not sure enough to order one yet.

Any advice guys? I was thinking I could do the Tranny Mount myself, and Sewell has a fairly good price.

Do you know what kind of condition your transmission mount is in?

Also have you ever had the transmission drained and filled? If not, you don't really know what's in there and I'd recommend to do it with OEM spec fluid. Can make a huge difference.

this is a problem with all sc's, ive asked around, i thought it was the trans mount too but i havent replaced mine, so if anyone changed their trans mount id love to hear some feedback, but i dont see how it could be bushings, i doubt it. solenoids are a good guess but im still unsure. i thought it was the subframe because i was missing some bolts down their but still the same.

You know what I'm about to just buy the damn mount, $75 shipped on Sewell after Club Lexus discount....worst comes to worst...I have a new tranny mount.

I've read before that this will fix the problem in another thread when I was doing research earlier in the year with my other SC... I want this one running perfect so I think I'm just going to bite the bullet and buy this later today.

Also check this thread if you are on the fence, and read it thoroughly. There are people with the same problem in an SC 400 and swapping mounts flxes the "clunk" noise.

Specifically post # 40

https://www.clublexus.com/forums/per...or-auto-3.html

I just bought the mount so I will do this on the weekend when I get the part. Another member recommended bushings for upper control arms, not sure I can do that job myself though. Either way I want my ride to be as smooth as possible, so I planned on replacing some suspension stuff regardless. Might as well start here.

I replaced my smashed, dry, and cracked OEM tranny mount with a new MTC mount for less than 45 bucks. And if anybodies wondering, this job is really easy. The hardest part about it is seeing if your work payed off...

but why buy a new mount? just tighten the old one!

3 reasons.

1: Tighten the mount to death, but the mount will still be smashed.
2: The transmission mounts are very inexpensive.
3: If symptoms even slightly point to bad mount, hy NOT do it?

Odds are, I'd replace it.

well if your mount is shot you have nothing to lose by attempting to tighten it, most sc's still have the original mount, aka: dont fix it if its not broke.

Well as I was sifting through the threads today regarding this issue I also stumbled upon this.... OLT's tweak tip... Apparently this is a remedy for the same issue. Now I already have a tranny mount on the way, and that's not going to change, but I do have off tomorrow, and I will give OLT's tweak a try on both of my SC400's and report results. If this fixes it I'll be shocked. A little reading goes a long way here.

Here's a link to his thread.

https://www.clublexus.com/forums/per...-shifting.html

My mount was in two pieces!!!!! but after i put that in and changed my trans fluid & the filter everything was smooth! I did feel some sort of clunk, but after the mount, it seems to be good, i also did get a mtc mount for 55$ so it was all good.

mtc? lexus told me not to flush my trans lol, i think they want my car to break down so they can tow it and charge me 12 arms and 4 legs!:D

Thanks for all of the comments and info.

Well, I changed the trans mount today and it did not help.

When I got the old one off it looked like it was fairly new (I guess the previous owner tried this too). I went ahead and replaced it with the new one because I noticed on the new one that I got from Park Place had a sticker on it that said REMAN, so I was thinking that probably meant remanufactured (not happy they didn't let me know this to begin with). My thought was, what if the previous owner replaced it with a remanufactured one and it was defective or failed early. Anyway, no dice.

Again, I can shift it from R to P slowly and feel something grabbing that I don't feel when shifting it at normal speed. When I shift slower into P I can go into R or D at a normal speed or even really fast and it doesn't jerk or clunk into gear.

Unless anyone else has any suggestions I can try draining and filling the fluid. Maybe the previous owner tried to keep the maintenance up and replace the fluid with the wrong stuff and it is causing the problem. I don't know.

Did you ever try calibrating your TPS? I had a jerk/buck/kick with my SC and it ended up being the o2 sensors, trans mount, and TPS. I know you're certain that it feels mechanical, but it might not be. It's really weird, actually...