Nasty sound when engine shuts off

Well I'm back agian looking for help with my 87 wag. Well I took the jeep out for the first test drive after the motor swap and killing all the germlins that I encountered during this swap.

I have rattling sound that seems to be coming from the exhaust(which was present before the swap) and I'm wondering what I can cure that problem

and I also have this nasty sound that happens when I shit the engine off, I know it's hard to explain a sound and even harder to reader someones explaination of a sound, but I'll give it a shot. It's a thud, that repets it's self three times, doesn't sound like metal on metal which gives me hope. Maybe engine mounts need replacing??

Thanks a million times over for all help in the past

Check the clearance between your exhaust and the trans crossmember where it is routed above the crossmember. Notorious for clunking there. New mounts may not be a bad idea either.

get underneath and shake the exhaust. bang on the catalytic converter with your fist. Could be busted cat or just the exhaust on the crossmember or even tail pipe rattling against something.

So both rattling sounds could be just from the exhaust? I'll check it tomorrow if the weather permits

Ok, hate to be overly critical, but you just did an engine swap and didn't inspect/replace the engine and trans mounts?

As the others have posted, you should check your exhaust system's mounting, but if your engine/trans mounts are wasted you could just be P/ing all over yourself.

Engine mounts looked good, trans mount had some cracks in it but was still solid(so I didn't think much of it) and the exhaust mount I can't remember.

I was in a hurry to get the jeep running since the house I was renting got forclosed closed on and the landlord gave me a week and a half to get my stuff out

what should I look for when I inspect the mounts?

87woody-atl said:

Engine mounts looked good, trans mount had some cracks in it but was still solid(so I didn't think much of it) and the exhaust mount I can't remember.

I was in a hurry to get the jeep running since the house I was renting got forclosed closed on and the landlord gave me a week and a half to get my stuff out

what should I look for when I inspect the mounts?

Click to expand...

Isn't that typical? You always have the most to do when you have the least amount of time to get it done.

Trans mount--crawl under there with a pry bar and a jack. First, try prying up and left/right on the trans, see if it moves around--it shouldn't, if you can move it with a pry bar then the torque is really going to move things around. Put the jack under the transmission, not the crossmember, and jack it up--there shouldn't be any free movement before the crossmember starts to raise--same thing again, if it can move it will really move under torque.

Same for the motor mounts, but you also need to check and make sure the brackets mounted to the block haven't lost or broken any bolts (common occurrence), then try the pry bar left/right/up--same, any movement with a pry bar will be worse under torque.

You can also have a spare set of hands sit in the drivers seat, engine running and trans in gear, parking brake on and foot on brakes, then rev the engine while you stand to the side and observe the engine's movement in the mounts.

Good luck.