Transmission Noise??

dylan7495 · **Posted:** Sat Jan 14, 2012 8:00 am

Hi Everybody,

Over the last couple of days my 04 CRD with 5-45RFE gearbox has been at the shop getting its tranfer case overhauled. This cost me $1000. The original complaint was as follows.

When driving at 25 to 40 mph and suddenly taking my foot off of the accelarator there is a fairly loud scraping or whinning sound comming from under the vehicle as the engine revs fall. it only happens at this speed, if i am going faster or slower then it is fine. I do not trust the mechanic anymore as i drove the car 10 miles to my residence and its doing it again. What does this sound like to you? Transmission?? Torque converter??

Any advice would be appreciated.

racertracer · **Posted:** Sat Jan 14, 2012 9:06 am

I have a question regarding the shop that performed the work.

What made the shop determine that the noise was coming from the transfer case and furthermore decide to rebuild it?

If they misdiagnosed the problem and if the repair they performed did not fix the problem, then I would demand a refund.

We need more info.

1. Miles on vehicle?
2. How many miles ago was the Transmission serviced with new filters and replenished with new Chrysler approved ATF-4 fluid?

dylan7495 · **Posted:** Sat Jan 14, 2012 9:17 am

I have demanded that they fix the problem at their expense but will have to wait until monday to get a response. I am not sure when last the transmission was serviced. I have followed the service schedule and the dealers have stamped the book everytime. (Not jeep but other service centres). The vehicle now has 189000kms (117464mi). I dropped the vehicle there two weeks back and collected it today . I do not know how they came to the conclusion that the Transfer box was the issue.

BTW..... The car does FEEL better.

racertracer · **Posted:** Sat Jan 14, 2012 9:33 am

I know that old broken down transmission fluid can cause serious problems, especially improper gear shifting and noise.

If the scheduled transmission service was not performed on a vehicle with that many KMs and in the high heat of S.A., then I would bet your problem lies with the old Transmission fluid doing a number on the tranny.

The problem may be just a simple transmission filter and fluid flush, although if it is too far gone then a transmission rebuild may be in order.

I know people who have eliminated tranny noise with a tube of tranny fix poured in the transmission dip stick, or used something like this http://www.youtube.com/watch?v=ikC_OUbqpRU

Note; if you choose to use this stuff and the tranny gets back to being normal again, you will need to perorm a flush and filter change to do the job right.

Keep us posted.

dylan7495 · **Posted:** Sat Jan 14, 2012 10:56 am

Wouldnt they have had to change the fluid if they overhauled the Transfer case. I am trying to order 05013470AC on ebay as the dealerships here charge a fortune. I am going to do the work myself. I have the knowledge etc to do this. I did inspect the fluid at the dipstick and it is absolutely clear although i get the idea it is horribly overfilled.

My biggest fear is that i drop the sump and find ground up pieces of transmission in there. $3000.00 is a lot of dinero to replace a tranny.

Just another interesting question. How would you know if the clutches in the transmission were done. What would it feel like driving the vehicle?

And another. What symptoms would there be if the Torque converter were giving up the ghost

racertracer · **Posted:** Sun Jan 15, 2012 3:25 am

The transfer case is not the transmission.

A transfer case is a part of a four-wheel-drive system found in four-wheel-drive and all-wheel-drive vehicles. The transfer case is connected to the transmission and also to the front and rear axles by means of drive shafts. It is also referred to as a "transfer gearcase", "transfer gearbox","transfer box" or "jockey box".

An overfilled transmission has been cause for problems in other CRD's on this board. I would syphon some of the fluid out using a bucket and a 10' long clear 1/4' diameter hose placed down the dipstick tube and bring the fluid level back to where it should be.

By the way, if the transmission fluid in your Jeep is not the specified ATF-4, then this maybe your issue too.

dylan7495 · **Posted:** Sun Jan 15, 2012 3:37 am

Hi,

I understand that. I just wasn't sure whether they used the same oil.

ATXKJ · **Posted:** Sun Jan 15, 2012 5:16 pm

The manual recommends the same oil - but it's not absolutely necessary
the Tranny oil is -and must be a Mopar +4 - the clutches and pressure plates are tuned for it exactly.

The transfer case is gears only - no clutches - so it could get away with a 5w-20 oil.
personally I'd go with the manual and use +4.

dylan7495 · **Posted:** Mon Jan 16, 2012 10:54 am

Ok get this. I brought the vehicle back to the mech today. The reckon that the noise is the turbo. And that its perfectly normal. Ok they say this is a dump valve noise. I didn't think these vehicles had dump valves.

papaindigo · **Posted:** Mon Jan 16, 2012 12:44 pm

Looking at the OPs 1st and last post let me see if I have this right:
1. original issue "at 25 to 40 mph and suddenly taking my foot off of the accelarator there is a fairly loud scraping or whinning sound comming from under the vehicle as the engine revs fall"
2. so they rebuilt the transfer case. Unless I am mistaken the insides of a transfer case are gears so any damage or lack of damage would or should be fairly obvious when the case is opened.
3. in any case the original issue is still there
4. the mech now says it's a normal turbo dump valve (aka compressor bypass valve) noise.

I don't know if such a thing exists on the CRD but I do know I don't hear such a sound and would not think such a sound would be produced by such a valve. However, you probably should pull the airbox to turbo hose and carefully inspect for turbo shaft play and/or contact between the turbo vanes and the sidewalls which could produce such a sound. Best inspect ASAP as turbo failure has been known to take the engine with it.

dylan7495 · **Posted:** Mon Jan 16, 2012 1:05 pm

papaindigo wrote:

Looking at the OPs 1st and last post let me see if I have this right:
1. original issue "at 25 to 40 mph and suddenly taking my foot off of the accelarator there is a fairly loud scraping or whinning sound comming from under the vehicle as the engine revs fall"
2. so they rebuilt the transfer case. Unless I am mistaken the insides of a transfer case are gears so any damage or lack of damage would or should be fairly obvious when the case is opened.
3. in any case the original issue is still there
4. the mech now says it's a normal turbo dump valve (aka compressor bypass valve) noise.

I don't know if such a thing exists on the CRD but I do know I don't hear such a sound and would not think such a sound would be produced by such a valve. However, you probably should pull the airbox to turbo hose and carefully inspect for turbo shaft play and/or contact between the turbo vanes and the sidewalls which could produce such a sound. Best inspect ASAP as turbo failure has been known to take the engine with it.

Will do. Right now actually.

dylan7495 · **Posted:** Mon Jan 16, 2012 1:12 pm

My question is why is it only happening in that gear? As the revs fall to idle. I mean it is less than a second. If I gun the engine in neutral and release the gas then its quiet. If the transmission doesn't disengage and holds the revs up it makes no sound either. It did seem quiter in general today. This started after an oil change. Done by the same mech. Could the wrong oil cause the turbo to fail? If the turbo were failing wouldn't it do it all the time especially when under load? If it helps any the noise seems worse when the engine is cold in the morning.

papaindigo · **Posted:** Mon Jan 16, 2012 1:26 pm

I think the turbo shaft/fin issue is a long shot but it merits checking and yes if it was the turbo you should hear things in a less narrow range of circumstances.

You have added a bit more to the puzzle which is the sound is very brief; does not occur at the same rpm range in neutral; and does not occur if the transmission doesn't disengage which I presume means the torque convertor doesn't drop out of lockup (e.g when you take the foot off the gas rpms drop dramatically). Essentially it only occurs under deceleration with the torque convertor locked if I am reading this right.

Makes me wonder if something is rubbing or vibrating against something else under that particular load. Perhaps loose skid or some such. This also makes me wonder about failed motor mounts; a not uncommon issue that can cause very odd under the vehicle noises according to past chat.

dylan7495 · **Posted:** Mon Jan 16, 2012 1:42 pm

papaindigo wrote:

I think the turbo shaft/fin issue is a long shot but it merits checking and yes if it was the turbo you should hear things in a less narrow range of circumstances.

You have added a bit more to the puzzle which is the sound is very brief; does not occur at the same rpm range in neutral; and does not occur if the transmission doesn't disengage which I presume means the torque convertor doesn't drop out of lockup (e.g when you take the foot off the gas rpms drop dramatically). Essentially it only occurs under deceleration with the torque convertor locked if I am reading this right.

Makes me wonder if something is rubbing or vibrating against something else under that particular load. Perhaps loose skid or some such. This also makes me wonder about failed motor mounts; a not uncommon issue that can cause very odd under the vehicle noises according to past chat.

I agree that the turbo is a good place to check. Let's just be clear. It happens when the rpm drops dramatically at the speed said above only in a particular gear(think its second) The sound seems to be at the same frequency/speed as what the propshaft / torque converter would be spinning. That's why I thought of the tranny to start with. Is the torque converter meant to unlock in this gear 2nd?

papaindigo · **Posted:** Mon Jan 16, 2012 3:05 pm

Which automatic transmission do you have 42RLE (4 speed I think) or 5-45RFE (5 speed)? I don't have a clue what the shift and TC lockup pattern is on the 42RLE but on a stock 5-45RFE, without the F-37 recall, between 25 & 40 mph I think you should be in 2nd or 3rd with the TC unlocked. In fact if memory serves the 5-45RFE won't lock the TC below 4th gear. In fact it's easy to tell if the TC is unlocked; if you take your foot of the "gas" and the rpm almost immediately drops to just a bit over idle then the TC was unlocked when you removed your foot. However, that doesn't match your comment that if the tranny doesn't disengage you don't get the sound which makes me wonder if you have the 42RLE and you are sometimes in 3rd at 35-40 mph with the TC locked hence when you let off the gas the rpms don't immediately drop.

Have you tried running the vehicle up to 40mph and at the same time you let off the gas shift the tranny into neutral? If not try that and see what happens.

Any link between the noise and whether you are coasting to a stop or using brakes (e.g. does using brakes make the noise start or stop)?

A sound that only occurs on deceleration with the drive train not under load (e.g. rpm near idle speed and TC not locked) still makes me wonder about vibration induced noise which could come from lots of places including - motor mounts, skids, exhaust system, CV joints, drive shaft "U" joint or slip joint.

Not much help I know but absent hearing the noise it's the best I can do.

geordi · **Posted:** Tue Jan 17, 2012 12:47 am

Not to shut down all of PapaIndigo's diagnostic suggestions, but I would point to the turbo for this, especially if it started soon after an oil change.

Two things:

1. The CRD does NOT have a "dump valve" on the turbo, it has a Variable Vane technology. The big vacuum servo on the top of the turbo is for these vanes.
2. The wrong oil CAN VERY MUCH KILL A TURBO, and it will happen ***quick*** You might get a few hundred miles from it, maybe a couple thousand. But with oil that is too thick, it won't lubricate properly when cold (like you describe) and if the oil is too thin, it won't put up with the heat and will not protect that bearing.

With the wrong oil (if it is standard oil or not diesel rated) the soot coming in from the fuel will coke up the oil, causing it to thicken and not pass through the amazingly small passages in places like the turbo bearing.

You need a full synthetic diesel rated oil, changed no more than every 6000 miles or so.

Dig into the airbox-to-turbo hose, and feel what that center shaft of the turbo is doing. If it has any significant play from side to side, that is probably where you are hearing the noise - It is contacting the housing when it is spinning down from speed. Why can't you hear it at idle? Easy - The turbo is computer controlled, and the computer knows your CRD is not in gear OR heavily loaded by pulling the body down the road. As such, it will not spin the turbo to the same speeds as it would when under load. Boost pressure is directly proportional to shaft speed, and you don't need boost pressure in neutral.

papaindigo · **Posted:** Tue Jan 17, 2012 7:32 am

X2 on geordi's turbo check details although in fairness to my diagnostic speculations checking the turbo was first on the list. He certainly does a better job of explaining why and settles the dump valve issue, so much for your mech's knowledge.

ibHenry · **Posted:** Tue Jan 17, 2012 8:17 am

dylan7495 wrote:

Hi Everybody,

Over the last couple of days my 04 CRD with 5-45RFE gearbox has been at the shop getting its tranfer case overhauled. This cost me $1000. The original complaint was as follows.

When driving at 25 to 40 mph and suddenly taking my foot off of the accelarator there is a fairly loud scraping or whinning sound comming from under the vehicle as the engine revs fall. it only happens at this speed, if i am going faster or slower then it is fine. I do not trust the mechanic anymore as i drove the car 10 miles to my residence and its doing it again. What does this sound like to you? Transmission?? Torque converter??

Any advice would be appreciated.

One question, did they give you a kiss after paying this bill, because they surely F'd you. :JEEPIN:

dylan7495 · **Posted:** Thu Feb 02, 2012 1:55 pm

Ok. took it back to the mechanic in question. He stuck to his story about it being the dump valve. I did read somewhere that pre 05 CRD's didn't have the the variable vane turbos. So I took the car to a turbo specialist here in silverton pretoria and he confirmed that the turbo does have a dump valve and he showed me a unit on top of the turbo made by Valeo that he claims to be the dump valve. So I dont know anymore. going to have to see what happens. he reckons the turbo is fine. :oops:

camo · **Posted:** Fri Feb 03, 2012 11:24 pm

I have that same noise when I let my foot of the gas pedal but it happens under TC lock-up conditions, and at operating temp. also, it is a bit louder if I press the gas pedal lightly after releasing it between 50 to 70 mph.
I already replaced the ujoints, turbo had been check, new motor mounts, and all else looks solid underneath. The only thing I saw, was a very tiny transmission fluid leak that happens only when driving and starts at about where the tranny mount is. Then it runs back to the transfer case where it drips but never leave a trace anywhere because first: it is very small. and second, it only happens when running. ant more ideas on what to check?
I have an 05 limited.
thanks

Transmission Noise??

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