[draker]

I just reinstalled the engine post rebuild. After finally getting it to drive I notice a rattle sound coming from the bell housing. It's intermittent, and doesn't seem to get worse at higher rpms maybe I just can't hear it over the engine. However it's most notable when idling. I haven't had much time to check into this issue, so I just thought I would throw it out and see what I should be looking for?

Thanks!

 

[alloro]

Are you sure your torqued down the flywheel and flex plate bolts? Any chance you dropped anything down inside one of the exhaust pipes when they were disconnected? Is the starter mounted nice and tight?

 

[97B2500CCV]

Hopefully all the tranny bell house to engine block bolts are tight as well.

 

[draker]

I will check the tranny/bellhousing bolts again, I am pretty sure they are all tight.

I don't recall if I torqued them down due to the space limitations, but went through and tightened them pretty tight. Maybe I skipped one and didn't get it as tight as I thought? I'll pull the starter and cover and take a look inside to see if there is anything obvious. It's possible something could have fell into the exhaust pipes, not likely however. From what I hear it doesn't sound like a pipe rattle and reacts to engine rpm changes. My first thought was flywheel/flex plate but if I recall I made a point to ensure they were tight. (Not necessarily torqued though..)

 

[alloro]

My first thought was flywheel/flex plate but if I recall I made a point to ensure they were tight. (Not necessarily torqued though..)

That could be a timebomb waiting to go off. Your idea of tight might not be even close to correct torque values. If they're under-torqued significantly they will loosen up in a relatively short amount of time.

 

[draker]

Well I finally got under the van to torque up the flywheel bolts.. bad news. I reviewed the torque spec 2 times to verify I wasn't going too tight. I was going in increments up to 55 lb-ft. Guess what.. I snapped off a bolt. So first.. is 55 the right torque? second.. does this mean I have to drop the tranny to drill this out or has anyone got any tips? It was a bad day under the van...

 

[97B2500CCV]

9.5- inch 3-lug=40lb
9.5- inch, 4-lug=55lb
10.0- inch, 4-lug=55lb
10.75- inch, 4-lug=22.5lb

Transmission will have to be removed in order drill out the broken bolt.

 

[draker]

Yep, exactly what I thought.. 55lb. Bolt may have been stressed from prior removal and install of new tranny. Well looks like it's coming down, and new bolts will be installed.. what a shame. Ah well.

 

[97B2500CCV]

Might want to take the proper tap and chase out the threads while the tranny is out again. New bolts all the way around is a good idea.

 

[draker]

I will do that for sure.. Don't want to have to pull it again! ah well, at least I can get a full view of what might be causing the sound if it's not the bolts..

 

[alloro]

Yep, exactly what I thought.. 55lb. Bolt may have been stressed from prior removal and install of new tranny. Well looks like it's coming down, and new bolts will be installed.. what a shame. Ah well.

I know hindsight is 20/20 but, you're not supposed to reuse those flex plate to crankshaft bolts, or the flex plate to torque converter bolts. The reverse stress applied while loosening them causes a weakness in them, as you just found out the hard way.

 

[B-300]

55 ft-lbs is to much for a 3/8" bolt... ARP rod bolts torque spec is 50 ft-lbs. and they are heavy duty bolts.

 

[alloro]

Yes 55 ft-lbs is to much for a 3/8"-16 (grade 8) bolt, but a 3/8"-24 (grade 8) bolt can take 59 ft-lbs. The torque specs for the flywheel bolts in his van is 55 ft-lbs (unlubed).

 

[B-300]

Crankshaft to flexplate bolts are 7/16"-20 thread if I recall correctly.

 

[draker]

I got the transmission down removed the broken bolt. I still don't see anything that stands out which could be causing the noise. All the bolts were tightened down pretty tight to the flywheel although not to 55lbs. Starter and the bell housing cover all seemed tight.. Is there anything else I should inspect before I reinstall it? I got all new bolts, I'll see if I have the correct tap as well to clean out the bolt holes.

Would it be a bad idea to start the engine with the tranny removed? I wanted to look at the drive plate too see if it's out of round or bent. Let me know, thanks!

 

[B-300]

So you been driving around with a broken bolt? (I thought the problem was solved.)
Check the flexplate for cracks. Also the inspecting cover might have been hitting the torque converter bolts. This is more likely if they hav been replaced with a hardware store bolt that doesn't have have the correct thin head.

 

[draker]

The van has been parked for months, hasn't been driven since the bolt issue. The broken bolt was from trying to tighten it up to spec. I just haven't had time to drop the transmission until 2 days ago. The bolts seem to be the correct bolts. I just went and got all new ones from Dodge. I'll check for cracks. What about starting the engine? bad idea?

 

[draker]

I don't see any cracks on the flexplate either. Seems ok. I spun the torque converter inside the transmission bell housing and it didn't make any noise either. I'll inspect the starter see if anything was rubbing on that.

 

[alloro]

Would it be a bad idea to start the engine with the tranny removed?

That would be difficult since the starter bolts to the bell housing and not the engine block, plus the torque converter has the ring gear for the starter. But if you could start it, the answer is no, you will not damage the engine. You will want to make sure the back of the engine is supported real good, since the tranny normally does that job. You also cannot start it with the torque converter attached.

 

[draker]

Oh duh! Forgot about the starter not even being hooked up.. :whackit: Well I'll do a good inspection.. and reinstall it. What's the Crank shaft position sensor gap spec, if there is one? It's sitting close enough to where it would rub if the outer lip of the flexplate was warped. It's sitting at an angle too, like the sensor mount might be bent slightly. I'll see if I can adjust it.