drivetrain noise from bad bellhousing?

[LukeG]

Does anyone know what the specs. are for the Getrag bellhousing alignment, or any bellhousing for that matter? I'm working on a '93 with bad noises and found that the bellhousing is not perfectly aligned with the crank, but how accurate is a used bellhousing? According to my measurements, the bellhousing sits . 010" high, the top of the machined surface the trans. mates to is . 008" closer to the flywheel than the bottom. Also had a ball bearing installed in the flywheel and it is off just over a thousandth, . 00125" roughly, using a dial indicator accurate to . 0005". Any info would be much appreciated. I have noise in 3,4, and 5th gears that gets worse with higher road speed while accelerating and cruising but not coasting, 5th is the worst,cruising noise is much less than under power. The rear diff. is rebuilt with only a few thousand miles but I haven't opened it back up, 3 new U-joints and carrier brg. in rear driveline and balanced, 2 different Getrag transmissions, one rebuilt, one used and tight that did not make said noise in other truck, used Luc clutch but decent shape, 205 completely rebuilt, bolts all tight in crossmember. The trans is set up with 0 endplay on both shafts 5 qts. Amsoil 10w-40 which Amsoil tech. recommended. Ideas??? Thanks again.

Luke

 

[RSchwarzli]

First though is just a sound, or also a vibration?



As for the sound, how old is the getrag? I have all sorts of noises from mine and I know it is not a alignment issue!

 

[LukeG]

I opened up the rear axle and found a tooth off of the pinion sitting in the bottom of the housing which surprised me. A reputable shop had just rebuilt the rear axle and had few miles, also the owner never mentioned anything other than a gradual increase in noise and vibration so I didn't expect broken gears. I appreciate the response and hope it wasn't too ignorant to post a question before I had apparently checked all possible problems. I am still curious if anyone has ever checked a bell housing as I did and what was found, still seems like it should be more accurately centered with the crank.

 

[DVolk]

There was a guy i sold my Fet junk to in Seattle that did the run out on a bell houseing all though he went to a nv4500 , im not convinced you need to do so , How couls you not install it correctly ? Ive doone 2 diffrent engines and had to change the rear seal on one twice as a screw up my dad put the seal on wet , oops !!!!! but never a issue , Id say the transmission is noisy , but im not shure about the oil , I know all the storeys and claims about Ams oil , its decent stuff but it might need a liitel boost though and they like extra oil in them . Although i do know the Six States the distributor for the NV4500 only recomends useing Redline oil and they recomend a mixed blend of there MT 90 and there other oil i for get now its in the shop they have had problems with all the other oils However i think 10/40 is too light

 

[NIsaacs]

Per my Cummins manual, the total runout allowed for the bellhousing circumference is 0. 008, same for the transmission mounting face. This is for the SAE style bellhousing's with the machined surface's. They also recommend taking into account the clearance in the rear main bearing. Lift the crank with a pry bar and check the clearance.



Nick

 

[JLEONARD]

. 00125" runout is nothing. YOUR measurement error is likely be more than that. (error includes set-up of the indicator, etc)



Been a while since I pulled a bellhousing, but isn't it located with dowel pins?

If it is they should be accurate. If not, then runout is meaningless.

 

[ENafziger]

Not a bad question at all. I think Getrags are just a cranky transmission. Mine is loud exactly as you describe. The intensity of the loudness goes up with boost.

It's one of the most miserable things about driving the truck, really. Every time I'm about to get in the throttle good, I shudder a little in apprehension of the complaining that the Getrag is about to do!

--Eric

 

[DVolk]

That was my thoughts on the bellhouseings they have dowell pins why do a run out to waste time ???? How can you mess up other than way over tighten bolts

 

[JLEONARD]

That was my thoughts on the bellhouseings they have dowell pins why do a run out to waste time ???? How can you mess up other than way over tighten bolts

There could be dirt or a ding in the bellhousing that would not allow it to mount properly.

 

[NIsaacs]

Since machines and humans can make error's, it's possible for a mismatched bellhousing, especially if it has been changed. I don't think checking it is a waste of time, especially on your own rig, it's not like you are getting paid



Sounds like with the pinion tooth broken you have found most of your unusual noises. It is also normal for the manual transmissions to complain when the Cummins is pulling hard. A mildly modified 1st. gen. will double the torque of a small block gasser.



I find that my '01 with the 6spd will make more noise than my Getrag, however it does have a little more power. Sometimes the Getrag gets a bad rap, but I like mine.



Nick

 

[GCroyle]

That was my thoughts on the bellhouseings they have dowell pins why do a run out to waste time ???? How can you mess up other than way over tighten bolts

There could be dirt or a ding in the bellhousing that would not allow it to mount properly.

Bell housing alignment is a critical element of the long service life of a clutch. If everything is in a straight line CRANK - CLUTCH - INPUTSHAFT parts are happy. One other alignment issue is angular misalignment, pinch a wire/debris/bracket between the mounting surfaces and the disc is trying to be a flexible coupling, doesn't work too well.



The engine adaptor on the Dodge uses 2 dowel sleves fitting into 2 precision holes. Even under good conditions and a careful trans installation these sleeves have been know to damage the matching hole often from heavy handed installation or pulling the cases together with bolts. Both the Getrag and NV4500 use bellhousings, do you mount the bellhousing first and then stab the trans or mount them as a unit? The 3500 that I own had been stabbed rough and it made a big burr in the dowel sleeve hole in the bell housing, damaging the precision alignment.



Concentric and angular alignment are very important to the life of the discs torsion damper, hub splines, pilot bearing, input shaft pilot surface, input shaft splines and transmission bearings.



In this installation I measured the bellhousing alignment of my 3500. Dodge Ram 1997 5. 9L NV4500 5 Speed Clutch Installation - YouTube



The situation that I think can cause the highest chance of a dowel sleeve problem is an engine or trans transplant, sleeve goes missing.



The comment on dirt, yup. True story.

We took a tech call on a local installation Ford 7. 3L. Shop claimed that our new F/W wouldn't engage the starter. He actually pulled it apart to return the clutch and F/W for our inspection. No issues found with parts. Visit shop, inspect truck. Situation: clutch was being "professionally installed" an invoice was being created. Shop was a hard dirt floor garage with a small concrete center pad, no room under the truck to pull trans out, just back far enough, very tight quarters. Starter mounts to trans case, not engine like Dodge. Inspect starter mounting surface on starter and transmission. Found big dirt booger stuck between starter and trans case, wiped off and reinstalled all systems OK.

 

[DVolk]

Yes the surfaces need to be clean and the use of alignment tools need to be used thats the rule of thumb in any clutch install . However Itwasnt mentioned if there is a aftermarket driveline installed of which can make noise travel diffrent than the stock unit.

 

[JLEONARD]

He also said that the alignment "error" was measured at . 00125" which is really negligible assuming it was done correctly.

So my bet is that noise is from the transmission or the newly rebuilt rear differential.

 

[NIsaacs]

The . 00125 is only the pilot bearing. On the bellhousing, the OP mentions . 010 and . 008, however per Cummins that should be fine, especially when you take into account about . 002/003 clearance on the mains. That would make the . 010 about . 004/. 006 well within reason.



Nick

 

[DVolk]

Ditto , My guess is the transmission or rear end ? I never measured play on any clutch install and ive got rigs ive abused the hell out of most of those are gassers but still the same thing . I wonder if oil isnt heavy enough in the rear end as well ?????????

 

[LukeG]

Here is a pic. of the pinion gear. There are cracks in between every gear, one tooth broken off, and the 2 teeth next to the broken one are loose and I can wiggle them but they wont come free. Is there any way this was due to bad gear contact when they were installed, or maybe just a manufacturers defect. The truck has 180k on the clock if its accurate. Also, the ring gear was fine except for a few small chips on the corners of some teeth.

 

[DVolk]

Is this just what you recently found ? If so id blame your oil . I run a minumm or 90 weight and ive been known to run 140 weight in it and i dont use synthetic in it .



Right after I bought my 92 the rear end ran out of oil . Beacuse of a bad hub seal , the dealer never looked in the rear end and it was dry so i didnt either , any how a few years later it grenafed and i rebuilt it useing parts from Randys ring & pinion I also learned after a few diffrent hubseal to use a speedy sleave to end the leaks

 

[DVolk]

Mine had at the time maybe a 130 k on it

 

[cerberusiam]

Looks like a Yukon gear set after minimal use. :-laf



Offhand, inferior parts would be my guess.

 

[LukeG]

Yes, I just found this and it had 80w-90 non synthetic oil that looked like chocolate milk even though it hadn't been in there for more than about 5k miles. I also think it was a factory Dana set of gears. A local shop said it was from shock loading and was fairly common to see and caused by aggressive driving. Are Yukon gears prone to failure? I have no experience with them. Also what causes the oil to get so much water in it, pretty sure the truck hasn't been swimming, and I have been dealing with this on my own truck for years, my only solution has been to replace the gear lube on a regular basis. Someone suggested that it was from moisture in the air that the axle sucked back in every time it cooled down after a drive. I wish I could figure out a way to prevent it, I know some people use the accordion breathers for atv's but they don't seem big enough to me. I'm going to rebuild the axle and I expect the noise to be gone, the bellhousing is hopefully close enough to specs. I know the dowels are in place and everything was very clean and torqued correctly in assembly. The bellhousing was not loose on the dowel rings, and was installed before the trans. I did not pry the crank up when I checked the bellhousing alignment, but the endplay was . 008". Thanks for the feedback also.