Engine/Transmission (1998.5 - 2002) Engine noise..not valves...what?

[rootmanslim]

Well as suggested, i got the valves adjusted (2001 74K miles) but the noise persists. Sound like a loose lifter, worst on cold start, goes away under load and decell. Just motoring along on level "tap,tap,tap,tap"

Mechanic says it might be injector pump drive as that is "a gear to gear system" and that I should not worry about it.

Of course my era Cummins is so noisy anyway (real trucks rattle) that you can hear it best from inside the truck with the drivers window open driving along.

Standing outside, at idle, hood up, the noise does SEEM to be coming from the left (drivers side) front of the engine but there is a lot of noise in general.

Thoughts/Opinions most appreciated.

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[dclassens]

I had a gas 02 that had transmission noise that sounded EXACTLY like valve noise. I had to have a new trans installed and after that the noise was gone. I know this sounds crazy but the noise came off the back of the engine (upper bell housing) like one of the back valves, rockers or lifters. my point is noises may be deceiving. just my $. 02

dave

 

[Joe Mc]

@ 74 k a valve adjustment probably wasn't necessary (@ 100k mine were still well within spec) but at least the adjustment removes that as a possibility.

With Dave's thought above I "think" the noise would change once put in gear? If your truck is an auto pop in "D", any change? then to "R" and to "N" - if it's a stick then while sitting w/"E" brake on place in 2nd and slightly release the clutch just to load the drive line for a second or 2, then do the same in R. If there isn't any change I would "think" the noise is not trans related.

Now does the noise increase/decrease in frequency relating to engine speed? If so, get a mechanics stethoscope and try to narrow down the area where the noise is loudest relating the engine. If no scope, use long extension and place one end right in your ear opening and probe the engine - actually works pretty good.

Possibility, check your stock exhaust manifold for cracks, usually between #4 & 5, get an inspection mirror and make sure you check under the manifold for black/soot. This can be done while the engine is off, or on. If you don't see any evidence w/engine off start up and you may see a change in the mirror (could fog) due to the exhaust leak if there is one. Could be a bad exhaust manifold to head/manifold to turbo gasket as well.

I noticed my manifold was cracked at about 135k or so, but that was almost 4 years ago so it's a possibility for you to look into. An exhaust leak can sound like the engine banging something bad so it's worth a look see.

Keep us posted.

 

[rootmanslim]

Yeah I thought of the manifold. Gotta followup on that. (Except noise is on intake side and right where my factory books show those three gears (crank, cam & injector pump) all meeting up. Nothing to do with transmission (it's an auto). Boost pressure, EGT and mileage have not changed in forever. (We are a 7200' and up). More to follow.

 

[DCreed]

gears are helicut, no way they are the noise. Be sure your flex plate is not loose or cracked. that is the most common cause of a sound like a rod knock or lifter tap that cant be traced to such a thing. there's an inspection cover on the pass side opposite the starter to check the TC bolts. If they are at all loose, change the plate and get a stouter unit like a lam or billet to prevent failure as the holes will "egg" from being beaten several times per second. The stethoscope is a great tool.

 

[rootmanslim]

Okay, you gotta put this is dumb guy English. What is a "flex plate" and specifically where is it located. what does it look like and what is its function. What are "TC" bolts and where are they? What is a "lam" or billet" and where would I get one?
I used a piece of plastic pipe (like a stethoscope) and the noise is loudest at the driver's side front, where the gear is mounted on the injector pump. You are talking about the opposite rear corner of the engine, right? thanks.

 

[blacksheepdiesel]

Translation: The flex plate is to an automatic what a flywheel is to a manual transmission. It has the starter ring gear around the outer edge and is bolted to the torque converter (TC) to transmit power from the engine to the transmission. It does have a tendency to crack and sometimes even break completely rendering the truck motionless. There are aftermarket replacement flex plates available that are laminated (lam) which is several thicknesses riveted together or billet which is cut from a single piece of steel. Either are much stronger than the original equipment design. I am sure most vendors of high performance automatic transmissions for the Dodge will be able to sell you one.

Godspeed,
Trent

 

[rootmanslim]

So you're talking about dropping the transmission out of the truck to inspect this flex plate?
Have to think on that. Neither my mechanic nor the dealer has seen one fail (and 75% of the vehicles here are TD Rams)

BTW, I note you have Borgeson, keep an eye on it, one almost killed me by coming undone, leaving me with no steering. They are not built to aircraft specs as an allen screw with a lock nut and NO safety wire would never be allowed in a plane. They have no place on a truck (like mine) that sees a lot of time on Forest Service washboard dirt. if it can shake loose it will. Had that piece of junk come apart 5 miles sooner, I'd be at the bottom of the Hoback river after a 60 foot plunge (We don't spend money on guard rails in WY). I sent it back with a long letter on how it SHOULD be made. I got back a check and no comment. I guess they didn't figure their product was worth defending, nor fixing, as I see it still depends on the jam nut and nothing more to keep it together.
Factory design is far superior as to safety, and replacing them every 35K is well worth the peace of mind.

 

[rootmanslim]

DC and BSD get the gold star. After putting it in park, setting the brake and locking my wife in the house, I fired it up and got under the thing (nice thing about 19. 5 Rixons & 265 tires). Got back to the bell housing and there was the noise. Took off the inspection plate on the bottom and the noise got louder. Shut her down and put a pry bar in there (gently) but nothing moved or wiggled. Now here's the question. The truck lives here 12 months a year but is only driven the 6 months we are here. 3000 miles per year is now the norm maybe 1000 hauling around the horses. What happens if I do nothing? You mentioned it could break (not good), could it screw up the torque converter? Should I wait to see if it get louder? I'm sure dropping the transmission & bell housing and fixing it would be a $1500-2000 job. Need some add-vise! Thanks!

 

[DCreed]

Should I wait to see if it get louder? Need some add-vise! Thanks!

dont worry, it WILL!:-laf Try the inspection plate on the pass side and see if the converter bolts are just a bit loose. you'll have to turn the motor by hand and check each one. that may buy you some time, but replacement is the only safe bet. Yes, the plate breaking CAN cause damage! not only to the trans but to the engine! picture a 50# steel weight spinning @ 2k RPMs inside an aluminum housing. :{ I just had my trans rebuilt and I skipped the flexplate and installed a triple disc TC, didnt take long for the stock flex to crack! I was actually thankful as I first thought it was a rod knocking!

Use caution when purchasing/installing a thicker plate as the pump drive depth will need to be checked for clearance or you risk damage to the pump.

 

[dclassens]

I know you think we are crazy but I have seen trans noises make valve hunting tech go crazy. I am a mechanic that works on snow plow trucks, 99% are gas chevy 1500 and 2500. It really is not that much work to spin engine by hand underneath with pry bar and UNBOLT TC from flex plate. Gently slip TC back a little bit. Then you can run engine without trans turning. This will rule out any and all trans issues.

 

[rootmanslim]

Okay here's my problems:
1. I have been through all 4 inches of the 2 volume factory shop book and cannot find any reference to an inspection plate on the passenger side rear of the engine. The only thing I found is the plate you remove to bar the engine over to adjust the valves? Is that it? IF NOT where (very specifically) is it located?
2. I can't see anyway to unbolt this flex plate (what I would call the flywheel & ring gear) from the torque converter. There are no bolts visible through the bell housing bottom inspection plate. So where do you access them?
3. The term "flex plate" is not in the index or trouble shooting part of the factory workshop book, so where did it come from?
Sorry to be so dense, especially as I was a Porsche mechanic back in the 356 days and a Cummins is simple compared to a 1600 DOHC Carrera! Thanks.

 

[DCreed]

the inspection plate is on the aluminum trans adapter that bolts to the back of the motor that the trans attaches to. this is also where you would access the TC bolts. it faces front, is about 2/3 way up the adapter on the pass side.

 

[rootmanslim]

Thanks, I'll look for it and see, if i can see, what's going on. On replacing the flex plate. Beyond my tool capabilities here. Any idea what the job will cost? Also any suggestion on a superior aftermarket replacement that is a direct bolt on (no other modifications needed).
This has been a good truck, except for the lift pump issues (bad engineering) and the Borgson fiasco (my fault) BUT when I think back to my 74' 350 Suburban that went 147,000 miles (in NY state salted roads) with one fuel pump, I wonder about "progress"!
But I sure can't afford a new 2500 4x4. Thanks again for all your help.
TDR is THE best group of folks ever.

 

[rootmanslim]

Well I found the inspection plate (right next to the "baring" pop out plug) Obviously not designed for use by humans when installed in the truck! I did manage to bar the engine around and inspect with a mirror and get a socket on the bolts. No bolts were loose, (wish Dodge and Cummins would get together on metric vs inches!), there were no cracks in the flex plate and no give to it in any direction. So... .....
I don't guess I'm gonna pay a fortune to have the transmission/bell housing removed.
Has a service visit coming up next month, so I'm gonna drop in Dodge's hands to see what they think.

 

[grimesja]

I am having a similiar issue. Under power the engine rattles like a gas burner with bad timing. Mellows out at about 2 grand.



What is the best bang for the buck in flex plates. 4wheelparts wants $500 for a BD.

 

[rootmanslim]

Test post for Victor from the real "Rootmanslim".

 

[DCreed]

I am having a similiar issue. Under power the engine rattles like a gas burner with bad timing. Mellows out at about 2 grand.



What is the best bang for the buck in flex plates. 4wheelparts wants $500 for a BD.

check injectors. I shattered my stock flex @ 500hp. and got a thicker SFI plate off Ebay for $125. the trick is clearance. there is no extra clearance in the converter drive to the pump for a thicker plate and it will often kill the pump in minutes! I made a 1/8" spacer for the bell housing out of aluminum so I could use "off the shelf" parts without issues later. A good trans shop should be able to check and ensure clearance for the pump drive for a thicker flexplate. Also bear in mind SOME companies will not warrantee parts if used with "billet" or "laminated" plates, so be sure its all good before making a purchase that voids your warrantee.

 

[grimesja]

DCreed,



I bought a new SPI certified flexplate. We tried to install it on the truck. We tightened up two bolts and could not turn the torque converter. I talked to Jasper performance (the vendor for the transmission) and PRM (the vendor for the flexplate). They both state everthing should conncet and move freely. I reinstalled the old flexplate and bolted the transmission back up. There is barely enough clearance between the stock flexplate the torque converter for the torque converter to turn. I have always seen about a 1/4 of inch clearance on most transmission changes.



Is it normal not to have clearance on the Dodge transmission? Did the 1/8 spacer give plenty of room? Do you think a 1/4 inch would be too thick of a spacer?

 

[DCreed]

what is happening is the slots in the TC pump drive is pushing on the pump due to lack of clearance. So, you can either A. make a bellhousing spacer as I did(I made mine from 1/8 T6 aluminum sheet and replaced the dowels with longer ones I made from IIRC, two 1/2" deep sockets; if you go 1/4" you will need longer bolts too. ) , or B. cut/grind the slots in the TC deeper about 1/4". And yes, Cummins/Dodge has minimal clearance.