MR2 Owners Club Forum banner
1 - 10 of 10 Posts

·
Registered
1991 SW20 Turbo T-Top
Joined
·
31 Posts
Discussion Starter · #1 ·
Howdy-ho fellow sexperts

I've got a 91T that's making a dreadful groan under unusual circumstances. While in gear, clutch out, any speed. Push the clutch in? No groan. Turn right? Whisper quiet.

But when you're turning left, and to a much lesser extent driving straight, there is a groan that emanates through the entire car and at the very least I'm sure comes from behind the cabin.

Here's some hopefully relevant stuff:
Innovative 75A motor mounts (Yes, the whole car vibrates, no that is not the sound I'm talking about). On a time crunch, I installed only 3 of these mounts at first, replacing the 3 mounts that were most damaged, so I drove for about 2 weeks with only the upper trans mount being stock, with no tears and everything was minty fresh.

Car has
-stock sway bars
-aftermarket passenger side axle
-4th gen swap, original 185k mile E153 with MT-90 in it
-ACT lightweight flywheel
-South Bend stage 1 clutch with the stupid ACT throwout bearing that I couldn't replace with a Toyota one in time
-Stock suspension
-Stock 91T wheels with super healthy tires
-Hung caliper on the driver side (very slight pull, doesn't make any sound when coasting so I don't think this is it)
-TCS single muffler dual exit exhaust

So most importantly, I never had this issue until after one Sunday where I did the following:
-Installed the last motor mount, which required much more effort than I thought would be necessary, possibly due to me torqueing the motor up
-Replaced the passenger side lower ball joint
-Replaced the front inner and outer tie rods
-Drained and refilled my trans (MT-90 out, new MT-90 in)
-Loosened all the hardware on and adjusted my exhaust

The mounts are probably the most relevant issue, as I had to use a bolt to lift the upper trans mount high enough to install the through bolt. After some scolding by my old man and the issue starting, I loosened all the mounts and allowed the motor to move to a more neutral position before tightening again. This had the result of reducing the noise significantly for about 30 miles. Now I can no longer be sure it's made any difference at all. Problem now being that it doesn't seem to have any effect.

The exhaust was another mystery, as the previous owner slam dunked the front exhaust hanger into a trach can so I only have the two rear. When I loosened the exhaust up it shifted significantly, and I began to question whether my hangers were in the right location or if God had forsaken me. With it tightened back up I've noticed a loss of one of my favorite rattling sounds, but wonder if the weight shifting and torque on the engine is making some strange harmonic.

The car has since been aligned and tracks straight if you close your eyes and imagine the caliper isn't dragging.

And before anyone suggests trying factory replacement motor mounts, I am not expecting an inheritance or winning mega millions anytime soon.

Hope someone has some ideas, love you guys!
 

·
Registered
Joined
·
69 Posts
I'd start by fixing that caliper, especially if it's in the rear. Either way you need to fix it, so might as well kill two birds with one stone and see if it also fixes the groaning. Seems like the most likely suspect to me, anyway. What happens if you brake while it's groaning?
 

·
Registered
1991 SW20 Turbo T-Top
Joined
·
31 Posts
Discussion Starter · #3 ·
The sound doesn't change under braking, but changes between on throttle and off throttle.

If you push the clutch in the noise completely goes away, which is what led me away from the caliper. I have new ones on the way anyways though so I guess we shall see!
 

·
Registered
1991 SW20 Turbo T-Top
Joined
·
31 Posts
Discussion Starter · #5 ·
See, that was my first thought as well. My only concern is that it only makes noise while the clutch is out in gear. If you push in the clutch with the trans in, say, 4th gear, the sound goes away. So everything should still be rotating, at least in my mind.

Come to think of it, my transmission did have a delicious speedo drive gear for a snack at some point prior to my purchase, I wonder if the fluid changes dislodged something? Though I find it hard to believe that the might of Japan's strongest abs plastic could withstand the overwhelming power of my little tugboat motor.
 

·
Registered
Joined
·
69 Posts
You did mention that you had recently changed the gear oil. The left/right sensitivity is a clue also. Wondering if maybe when the clutch is disengaged the input to the diff is freed up and somehow making noise because of that?
 

·
Registered
Joined
·
69 Posts
So if it's only making noise when the clutch is engaged and the car is in gear (ie the engine and trans are connected, pedal is up) then I might suspect something to do with the differential. Seems like the noise occurs when the input to the diff is constrained. Is it a limited slip diff?
 

·
Registered
1991 SW20 Turbo T-Top
Joined
·
31 Posts
Discussion Starter · #10 ·
With the vehicle in the air the wheels turn opposite directions. In my experience that's an open diff but I could be wrong I suppose. I've recently noticed another groaning noise on the highway when coasting or maintaining speed around 60mph. I should note that the fluid that came out of the transmission looked fine and I've never had any issues with it otherwise.
 
1 - 10 of 10 Posts
Top