zegnaguy

iTrader: (1)

What is the problem and what needs to be replaced?

Rear end sloppy moving left and right. Only happens under Excelleration

Happening on 93 sc300 NA -6spd. (Miles 245K) Noticable everytime you hit the gas semi hard. Rear of car immediately feels like it sloshes to the left then back right, side to side the rear wheel must still be going straight. Only evens out when you let off the gas. Happens at low speeds and highs even scarier.


History Suspension and Drivetrain work:
-All 18 oem suspension bushings replaced with Diazen poly bushings. Front, back, lower, upper, sways.
-Tein flex Coilover.
-Diff (4.27 auto no LSD) drained 300 miles ago before problem. replaced with oem recommended 80-90diff fluid. no gray liquid or shavings.
-Single solid drive shaft from 6spd to custom diff adapter.
-Alignment done 300miles ago

When first installed 6spd this problem didn't occur it progressively started happening until really bad right now.


What is the problem and what needs to be replaced? What are the signs of axels/joints going out? Could it be the diff pumkin bushings wore out front or rear. wouldn't think they would cause this much flex more wheel hop if anything.

what kind of tests can I run to find out the problem?

Na-t comming next month so need to solve this before even more power than stock.



Everybodies Input is appreciated!!

GSteg

iTrader: (15)

This seems to be a problem for lexus. The way they connect the rear suspension frame to the chassis frame is through rubber bushings, at least on the GS. The rear end wiggles when you exit out of a turn and such.

We tackle this problem by using lower rear chassis brace of the Tom's 6 link. They are metal braces that makes the connection from the suspension frame to the chassis frame more rigid.

mkorsu

I know you said nothing appeared loose, but did you confirm that the rear sway bar endlinks are OK? Sounds like something is not connected on the rear sway bar.

zegnaguy

iTrader: (1)

The swaybar links are on tight with the locking tab pinned against the arm etc. Which side do the nuts of the links sit on? Nuts on inside facing diff or outside facing shock/wheel? I did take them off and put them back on but the problem didn't arise right after I did that. it was driving fine. I don't know if 245k on them would cause this big of problem. New ones would definitely be better but wouldn't think would fix this large of problem since the problem wasn't there after I reinstalled all suspenison and had the 6spd in.

O. L. T.

iTrader: (17)

moved to proper forum....

mitsuguy

iTrader: (2)

It could also be the upper rear control arm bushings... these are kinda tough to diagnose, but will definitely cause the sensation you are having...

They can also appear tight, but still have a little play (enough to cause this)

zegnaguy

iTrader: (1)

I will certainly check the upper control arm bolts are tight with torque wrench along with the rest of the bushings I put in. Nothing looked loose last night

KEEP THE IDEAS COMMING!!!

Dougspeed

iTrader: (2)

Have you checked your tire pressures? The last time my car did that, I checked my rear tires and one was really low because of a large nail was causing a leak.

Rotarytoy

Do an alignment

Slow_go_400

Do you have inner tire wear problem? do an alignment.

zegnaguy

iTrader: (1)

alignment done 300 miles ago. Doesn't pull or snow plow like it did before the alignment. He was it was all with in spec. In fact i had to raise the rear end an inch for him to get in spec from the orginal coilover drop I gave it. Drives straight.

cip

Mine did that, too. They replaced the upper rear control arm and the rear 'wiggle' is gone.

zegnaguy

iTrader: (1)

Interesting, because I repleaced the upper control arm bushing with poly bushing in addition to all the lower ones.

So did they attribute the problem to the old bushings on the uppers or the ball joint?

cip

well, looking at the work order it says "R/R upper control arm is loose. Replace the R/R upper control arm"

So it does not say exactly what was loose or what was wrong. But replacing the CA fixed the problem; I can say that much

zegnaguy

iTrader: (1)

so you had the same problem of pressing on the gas and sloshing from side to side? just under acceleration? becasue I if I take my foot of the gas and corner hard its stiff and doesn't slosh around its controled. So that leads me to beleive it drive train related since it only happens under excelleration.