TexLexSC400

I did a quick search thru the archives and didn't see anything on this.

I have what sounds like a speedometer cable vibration (thunk, thunk, thunk noise) that only appears between 20 and 30 mph anf follows the car speed in frequency. It's very noticeable when slowing down but can be heard briefly upon acceleration. The noise seems to come from behind the dash on the passenger's side maybe down towards the transmission.

Anybody had the same problem?

Can you "lube" the cable and if so, how do you get to it? Does the speedo work off a sensor on the transmission?

Thanks -

BTW - This is probably one of the most outstanding forums on the net when it comes to information and participation of members!!!

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'94 SC400 Pearl White Stock
latest addition - 245/50 Firestone SZ50EP - Great tire...

strongsail

the car doesn't have a speedo cable. The speedometer gets its signal from one of two VSS's (vehicle speed sensors) in the transmission.

I have read that the rear transmission mount is a known issue, and there's also a large heat shield in that part of the trans tunnel. Either could be transmitting drivetrain vibration into the interior. Sounds like it's time for a good look underneath...

TexLexSC400

Thanks. I'll take a look tomrrow when it's cool. I can put it on the rack at the shop on Monday.

The only "noise" that I need to fix is the noise blower motor on the AC. I'm sure that's a chore. Anybody done that and have advice?

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'94 SC400 Pearl White - Stock

boredguy77

where in tex r u? if you need some help I am willing to come by and help. just pm me if u want.

TexLexSC400

I'm in Houston (West side - out Sugarland way).

Appreciate the offer but I have full access to a shop to do just about anything I need.

I did narrow the noise location down to the Transmission/gear shift area today (tough to drive & listen at the same time).

Will probably put it in the air on Wednesday for a look see.

808state

sounds like what was discussed in this thread...
https://www.clublexus.com/forums/sho...d&pagenumber=1

i also had the knocking noise from the center console area by e brake/gear shift area. lexus changed out the drive shaft & center support bearing. no noise... thank goodness for warranty!

or it could be
https://www.clublexus.com/forums/sho...t&pagenumber=2

hope this helps and happy hunting!

TexLexSC400

Yep.. Sounds EXACTLY like what is in the first thread (Drive Shaft/Center Support Bearing at 20 to 25 mph).

I'd never even thought about that but was looking through the 1990 Lexus Shop manual at the garage yesterday. Just hadn't gotten that far yet.

I've got an extended warranty so hopefully, it will be covered.

Thanks for the detective work.

healerhand

Its the odometer motor going bad. I had the same problem. Changed the odometer. No more noise.