Grinding in 4th & 5th only when warm

[TravisPalmer]

RE: 1992 regular cab, long box, ram 2500 4x4 w/intercooled Cummins & getrag. Please don't fall asleep reading this. This is a lot to ask of everyone. I have a grind, much like a grinder on steel w/out hearing the grinder motor, in 4th, but even worse in 5th. The noise is not present when cold, but after 25miles or so, it starts and gets worse and worse the hotter it gets.

If I float it just right, or it's above 1500 or 1600rpm, or I push in the clutch it's gone, and it seems like when hot @1200rpm, just as I gently go from float to coast, it pops out of 5th. And If I put a little pressure up in the stick in 5th, I get an oscillation on the stick, unlike the smooth vibration felt when pressure is applied either up or down on the stick in all other gears(not that I would do that for any other purpose other than testing).

A local transmission shop put a bearing kit, surfaced the flywheel, and installed the replacement clutch kit in it, per the dodge "noise below 1400rpm bulletin". The shop has since gone into the t-case,rear end,and the transmission twice and assure me that all the bearing preloads are between . 000 & . 005, and the noise is more quiet, but definetly still there. If it gets hot enough it rattles the t-case shifter. I checked the bushings on the shifter, and they are in brand new condition. The new clutch also hops when I engage it in reverse & sometimes in 1st, the old one did not. 5th didn't pop out before the shop went into the transmission either.

They are not sure what oil is in it, but assured me it was overfilled.

The truck has 3. 54 gears and when I road tested it against the bulletin chart for minimum gear selection speeds, which the noise should no longer be present at or above, I got 50 instead of 30 in 4th, and 60 instead of 45 in 5th.

What frustrates me is that it seems natural to begin each gear (if your empty)between 1000 & 1200rpm, it has plenty of power at those r's, even up hill, and doesn't seem to lug at all. Well, at speeds in town, between say 35 and 50, that's in the range that it makes the most noise, and I dread having to get off the freeway. However, it shifts wonderfully, up or down.

When I talked to the shop they explained to me that the gears look brand new, and the noise is completely normal for a transmission of such size behind a cummins, and that I should stuff the boots if it's too loud for me. So I stuffed the boots with an assortment of various squishy materials, and settled on part # Owens Corning pink panther fiberglass insulation, it has the best noise dampening characteristics, even over the wifes bag of cotton balls. STILL ENTIRELY TO LOUD FOR ME!!!

I have trouble believing that dodge would have sold many trucks in 1992 with transmission's that noisy, if that is the case. I could believe that if the production date was say-1945, or it was a 1975 Kenworth log tractor! (nothing against kenworths) Furthermore, when I have towed or climbed a hill, it gets really loud, and I'm afraid something is going to break.

It may sound that I find a little humor in my dilema, however, I'm only trying to laugh a little about it, instead of using my truck for munitions testing, or flame spread analysis, especially cause I sold a perfectly good chevy td,( except for the 9 mpg)to buy this truck!

I feel as though you are my last resort, The shop had the truck for almost a month, and I've paid over 2500 bucks to get rid of the noise, and I'm terrified to either keep driving it as if nothings wrong, or take it back to the shop and possibly spend even more money, and down time, w/no result. These are the questions that I need answers to, that I can think of right now.

(1) I can hear a chatter when i lug it at 1100rpm or lower in 4th especially, and this seems normal, but a grind all the way up to 15 or 16- can this possibly be normal? And if not, any idea what to look for?

(2) As far as my shifting range, is it normal? the shop told me that I should be shifting much higher to stay out of that lug induced grinding, but that would mean starting at 1500, and winding out to over 2300 in 3rd & 4th, just trying to hold an in town speed limit, is this true?

(3) And what could possibly happen during a bearing change out, to cause 5th to suddenly start popping out in such a mysterious, inadvertent way?

(4) Could I still be having a clutch harmonic problem? This is the third one. I have the full power screw turned up, but the most boost it develops is about 25psi under "everything it's got" while loaded. Who, What#@*^><***!!!?

Any help, drawings, instructions, manuals, links, pdf's, or especially your answers would be extremely appreciated. I think my truck is beginning to control my behaivior, as I don't drive in town w/ out the radio blasting like a teenager, and w/earplugs in, and the driver (thats me) loudly saying "la-la-la-la, I can't hear any problem"!!! :{

Many thanks, I sent this directly to mysteryman as well, as I wanted to see if engineering had these sort of problems/solutions. but I'm new to this computer stuff, and I could not figure out how to specifically send this to him, and everyone else as a post. So iI sent two. Hope I haven't hurt anyones feelings. Maybe someone could help me out with that one too, but it's just fine if you don't. After you folks, I think i'ts going to be my first visit to the shrink(just kiddin). Many thanks, after weeks of researching threads and other sources, I cannot find a duplicate problem/solution. However I'm certain that if we can solve this one, it will be a invaluable thread for others. yours trully, Copperlittle! PS: other than this problem, I do absolutely love the power and economy(20mpg) of my new solid steel iron love button!!!

 

[JLEONARD]

I need to be above 40 in 5th gear (I also have 3. 54 diff ratio) if I am cruising along on flat ground... . a very very easy acceleration at that speed is ok. If I need to accelerate normally the transmission makes a noise..... I would not call it grinding, but whatever it's noisy. Above 50 it's fine.

I don't take mine up to 2300 in every gear... more like 1800 plus or minus.

From what you are describing I thnk you are lugging it too much... you need at least a few hundred more rpm in between shifts.

And it IS the low rpm shifting and loading on the transmission that will take it out. Most systems like rpm to handle the load. The bearings (transmission) do much, much better at higher rpm.

So... if higher rpms make the transmission live, and don't bother the engine, what's the problem?

 

[JGrefenstette]

when i first bought my cummins i short shifted it like crazy. i wasnt used to the I-6 diesels low rpms and was lugging it way to much. i put a tach in it, and now i shift at 2000rpms every gear. if im in traffic or have a slight load, 2200 is more comfortable. unless youve done a governer spring and dont have proper valve springs to go along with it, dont be affraid to put it to the floor and hold it, as long as your egts are ok. ive hit my govnerspring. 2700rpms, you hit it and the motor falls right on its face, boost falls, total loss of power. dont be affraid to wind it up. if your empty though, its totaly normal to drop down to 1100-1200 with an upshift. the getrag seems to have an 800-900rpm gap between gears, so youd really have to wind each gear to start at 1500rpms. that will kill you milage, and **** off other drivers if your crankin it up that hard every gear.

 

[TravisPalmer]

I shift exactly as both of you do, the shop is telling me that the noise I am hearing is lugging all the way up to 1500 or 1600, and that I should not turn the motor any slower than that, EVER! And why does it go away under the conditions in my post? Also, I get 23mpg the way I shift it, the way you guys are describing, I even occasionally put the hammer down and take it all the way to 1200egt, and the governor, and still get 23+mpg! However, if I stay out of the noise range(above 15 or1600), I get 17mpg, thats a big deal when I drive 250mls a day and pay $4. 75/gal. Further testing today found that when I push in the clutch to upshift, I hear a loud clunk from the bellhousing, the same clunk I hear when quickly letting out of it to coast, from full power. And if I push in the clutch to where it just starts to slip under slight load (while in the noise range)my dreaded grinding noise goes away, that indeed deserves an explanation!!! Oh yeah, also clutch is starting to hop starting out in second now.

 

[PToombs]

I wonder if the shop screwed up something in the clutch, throwout bearing, etc. A popping noise is more likely from that area, but not normal from a transmission.

I would also check what oil is in it. You should have 10-40 or there abouts motor oil in it, 1 quart overfull. If it has gear oil, it won't get the proper lubrication to the bearings. I don't run mine below 16-1800 on the flat, empty. Loaded or on a hill, I wind it up. It's good for it! :-laf

 

[JGrefenstette]

i agree with pete. you have to be real anal about these getrags. i think i put 10-30 in mine, but overfilling it a quart is what matters most. i also try to keep it over 1500rpms at crusing. if i hit a hill, even empty, if im below 1800rpms, grab a lower gear and let it eat.

 

[JLEONARD]

I don't run mine up. . I spend a lot of time "idling" along in 5th or 4th (on a flat or downhill) if that's how the traffic is moving... I just don't lean on it hard until I get some rpm. I don't lug it up a hill.

The clunking noise is definately a problem. I'd take it back to the shop that did the work and demand they break it down to check things out.

 

[dpuckett]

Ask the shop what the bearing preload was set to on the maindshaft. Get numbers, not "It's withing specs. " If it was more than . 007-. 008 pre load, they got it too tight and owe you another bearing kit.



1100-1200RPM is entirely too low for the Getrag. The engine will take whatever you can dish out, but the transmission likes to be above 1500. You dont have to accelerate real hard to 2200rpm, but get there at the pace of your choosing, and then shift. If I drive at less than 1500 RPM, then try to accelerate, my EGT skyrockets (relatively, anyway). If I wait til about 18-1900 rpm, then it stays more reasonable.



Where do you live? Maybe you could offer some fuel or beer money for someone with more experience with these trannies to take it for a spin. I wouldnt trust most shops to rebuild a Getrag. I know of one in Poplar Bluff who knows a little about them, but still not as much as we here in the TDR.



BTW- welcome. Too bad you have to get an introduction with this kind of issue.



Daniel

 

[TravisPalmer]

The shop says I owe them another $700 and something for replacing the rear end carrier bearings. So I am not going to take it back to them for any reason. Maybe someone in my area is thirsty? I live and work between north west & north central Oregon. (Portland to Madras) Anyone? Also does anyone have a issue where noise gets louder with how warm the transmission gets?

 

[JLEONARD]

It sounds like they preloaded it too tight... ie not enough clearance... when the steel gets warm and expands, the clearance get too small and results in noise.

Perhaps they are figuring it will "wear in" but proper clearnce should do that without making noise.



This is why it's important to pay with a credit card when possible... . at least you can out payment into limbo for a while thru the credit card company.

 

[dpuckett]

. This is why it's important to pay with a credit card when possible... . at least you can out payment into limbo for a while thru the credit card company.

Sometimes you can, sometimes you cant. I tried that with a credit card after a shop did a shoddy repair that left me stranded in Minnesota, and they said they (card company) wouldnt put a hold on it, as it had already been paid to the shop, or some crapola like that. I paid off the card and cancelled it.



DP

 

[JGrefenstette]

Also does anyone have a issue where noise gets louder with how warm the transmission gets?

ive actually found that with the getrag, along with most other manual trannys ive driven, are the stiffest, loudest, and most 'cold natured' (grinding, etc. ) when they are cold. sometimes my getrag stays stuburn even after the cummins is at operating temps. takes for ever to shift gears, dosnt want to go into the next gear, mainly 3rd (its the worst by far), 4th is getting worse, and 2nd will sometimes be a pain if im sitting still, but thats normal for a manual trans when your still.

 

[TravisPalmer]

So I talked to the shop & they said it had 80/90 in it, so I changed it out to 5/30 mobile 1. shifts like a dream and Idle noise in nuetral went away. Still lotsa noise when warm, so I jacked her up, put it in gear, and crawled under there with a pipe to my ear. What did I find? Tin plates on diff and transmission, quiet and smooth. However, t-case plates emit a loud sound like dragging a wrench on the ring gear, hmmmmmm. And I figured out why they went into the rear end. The grind I heard from there was a shoe retaining spring that snapped off and was rubbing on the drum. Seems like a more likely cause to me, it went away when I fixed it. So I think I'll take my 1&1/2 piece of abs pipe down to the shop and let them have a listen to that t-case, and see if everything I've paid them was in vain. Ill let you guys know.

 

[AMoffat]

I found your postings very interesting. I am unable to find any answers to why the clutch chatters (for lack of a better word) when starting out in reverse, and sometimes also first. This clutch only has 50,000 miles, and this problem also occured on another 93 Dodge I had with an almost new clutch. Could this be an engine mount problem, clutch linkage, . I have searched this site, and others but can not seem to find anyone with any answers. Andy Moffat

 

[pepecat]

Your chatter - would you say it is once per revolution or a flurry/fluttering of chattering throughout one rev?



Has your flywheel been resurfaced? If so, it may have been done improperly and is not a true plane for the clutch disk.



For the reverse only and first gear chatter I would guess that has to do with normal clutch operation with worn/weak engine/trans mounts. what is happening in the low gears is the clutch is fully engaging momentarily, torquing the entire driveline (too much play in the rubber engine/trans mounts) until maxed out, breaking the clutch loose, reliving the driveline tension/torsion and repeating - all of this happening over and over again for each 'chat' of the chatter.