Hello and thank you in advance for your help.

First the background: I picked up a stock 94 Del Sol SI that had a blown engine. I installed a rebuilt D16Z6, a rebuilt S20 transmission from Syncrotech, Exedy clutch kit and a new flywheel/bearing. I also replaced the clutch slave cylinder and spent quite a bit of time bleeding it. I put two quarts of Honda MTF in the transmission.

Here is the problem: Everything sounds fine at cold start but after about 30-45 seconds, a loud rattle begins in the transmission housing. The rattle stops when I push the clutch in. From reading the forum, this is an indicator of a bad input shaft bearing. But it is a newly purchased rebuilt transmission from a reputable company, and the shaft looked and felt solid when I turned it a few times prior to install. I really want to say it is not the transmission.

The fact that everything is new/rebuilt and the 30-45 second delay before it first starts rattling (when it is cold) throws me. I took the transmission back out, re-inspected everything, and carefully put it back together only to have the same exact symptom. I’m a bit stumped and not sure what to do next.

The transmission shifts smooth, no grind, and the noise goes away when the clutch is pressed to the floor. The clutch kit and flywheel are new. The input shaft bearing feels fine too.

Is there something besides the input shaft bearing that could cause the noise?

Thanks!

 

Bump for ideas.

 

So I got back into the service manual and found a caution: "If there is no clearance between the master cylinder piston and push rod, the release bearing is held against the diaphragm spring, which can result in clutch slippage or other clutch problems." The push rod looked screwed in all the way so I backed it out some. Started the car, rattle came back about a minute into it but not as bad. I let it run for a few minutes and it went away!

I'm not sure if I just needed to let the new transmission work itself in or it was the push rod clearance. I'll do a proper pedal adjustment now and I should be good to go.

Thanks for reading, I hope it helps someone else in the future.

 

Thanks for posting this, same thing with my 93 Del Sol Si. I put in a new clutch, flywheel, etc.. and I have a slight noise coming from the tranny with the same symptoms you described. Eventually I will have the tranny rebuilt... maybe...

 

Maybe you need to adjust the rod some more?