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View Full Version : Transmission noise/vibration cured with DARF


NelsonSprinter
08-27-2010, 12:23 AM
TODAY I had my '02 NAG1 Auto transmission serviced with Dr. A's DARF cure, and can't believe I'm driving the same van. NO Noise, no vibrations throughout the van at certain RPMs, with no changes to the driveline/shaft bearing support, no change in oil levels, just DARF's precision hole drilled with easy but exact instructions. That Rumple Strip noise and shudder is gone and hopefully soon forgotten. Thanks Andy, the SPRINTER FIXER UPPER.
Buy a DARF KIT today from Dr. A. :thumbup:

Drew.eight
08-27-2010, 02:40 AM
Which drill bit did you use? The .05 or the .04?

Thanks, Drew

kkanuck
08-27-2010, 04:07 AM
Which drill bit did you use? The .05 or the .04?

Thanks, Drew

I did .05.


I just drove 1000 miles, and really did not notice a fuel economy drop

NelsonSprinter
08-27-2010, 04:35 AM
#5 drillbit used

Aqua Puttana
08-27-2010, 11:48 AM
#5 drillbit used

So nobody makes a big mistake, I don't believe it was a number 5 drill bit. A typo maybe?

#5 drill bit = 0.2055" or 5.220 mm

If my memory is correct, I used a #56 drill bit for my early DARF Doktor A test trial.

#56 drill bit = 0.0465" or 1.181 mm

#5 is WAY bigger. It's unlikely anyone would be confused if they chucked up the #5 drill bit and lined it up, but you never know....:bounce:

vic

Drew.eight
08-28-2010, 02:43 AM
He sends a 55 and a 56. I just didn't want to let the cat out of the bag..... I guess you still need to buy the kit to find out where to drill... Just wondering what most people are using before I do mine. The paperwork says the smaller one is for maximum fuel economy. Does anyone know what the mpg difference is between the 55 and 56??

Thanks,
Drew

still patiently waiting for my D.A.D

kkanuck
08-28-2010, 03:04 AM
He sends a 55 and a 56. I just didn't want to let the cat out of the bag..... I guess you still need to buy the kit to find out where to drill... Just wondering what most people are using before I do mine. The paperwork says the smaller one is for maximum fuel economy. Does anyone know what the mpg difference is between the 55 and 56??

Thanks,
Drew

still patiently waiting for my D.A.D



Sorry.

I did the larger, the .056, and did not notice any real difference in mileage on my 1100 mile journey recently.

bc339
08-28-2010, 03:11 AM
I'd guess minimally. I ended up using the larger bit - really didn't want to do it twice if I still had RSN if I started with the small bit. I haven't noticed a drop in MPG's - maybe 1 or 2 at the most. But it's also hot and running both AC's really cuts the mileage. I'll know better when it cools off.
Shifting is incredibly smooth now.
Bruce

Aqua Puttana
08-28-2010, 03:18 AM
Oops. I thought the basic procedure had been outlined already.:doh:

So I didn't consider it a secret.:shhh:

The DARF kit from the good Doktor A is worth his price to make certain you have everything you need to do it correctly. Even if you are not plagued by RSN, my transmission just seems so much smoother after the modification that it's worth doing the mod for that alone. I haven't noticed a mpg decrease, but I'm not a calculate mpg with every tank type person either.

vic

Mr. Pixel
08-28-2010, 04:33 AM
Pardon the :2cents: from a non-owner and newby on the forum... but...

When I was surfing around the forum and saw "RSN" I thought to myself "Rumble strip noise? Naw... has to be a coincidence." But it wasn't. When I read the posts from Doktor A talking about the torque converter bypass clutch, I was floored.

You see, I had hands-on experience with another vehicle a number of years ago with the very same problem, and had a several-month-long dialog with the manufacturer's engineer assigned to the issue while we mutually diagnosed it. In that case, it was discovered that bypass clutch slippage was prematurely aging the transmission fluid, causing the fluid's friction constants to fall out of the engineered range. They kept messing with the shift control computer to change the hysteresis points (upshift/downshift spread) by delaying lock/unlock action to keep slippage under control. But it turns out that the real solution was to change the fluid 4X more frequently than the originally recommended 60K miles. Also, we learned to absolutely avoid aftermarket fluids with synthetic oil components, which exaggerated the slippage.

Also, that transmission was only concerned with 100% lockup in the tallest two gears, not all gears, nor a variable bypass. So Andy's fluid relief orifice trick is clearly genius. Heck, beyond genius. But hopefully without getting into probably painful, old discussions, I still have to ask - has anybody attacked this bug by changing the fluid?

bc339
08-28-2010, 04:47 AM
But hopefully without getting into probably painful, old discussions, I still have to ask - has anybody attacked this bug by changing the fluid?

Yes, but as you discovered in your experience, it eventually returns. Most, if not all of the Sprinter RSN's, have happened right off the dealers lot. But being new to Sprinters, most didn't know what it was until sharing information on this forum.
Thanks for your insight.

Bruce

abittenbinder
08-28-2010, 05:13 AM
Also, that transmission was only concerned with 100% lockup in the tallest two gears, not all gears, nor a variable bypass. So Andy's fluid relief orifice trick is clearly genius. Heck, beyond genius. But hopefully without getting into probably painful, old discussions, I still have to ask - has anybody attacked this bug by changing the fluid?

The Sprinter's TCC is activated in ALL 5 gears via very aggressive program maps.

When activated, the Sprinter TCC is always in a slip mode with a duty cycle ranging from 5-95%.

Some owners have noticed reduced RSN as fluid ages, some with fresh fluid.

Reports of significant overfill of fluid have shown reduction of RSN which I attribute to (potentially destructive) fluid foaming resulting in a commensurate reduction of pressure and damping of the TCC spool valve circuit's fluid pressure. Doktor A

Aqua Puttana
08-28-2010, 01:03 PM
....

Reports of significant overfill of fluid have shown reduction of RSN which I attribute to (potentially destructive) fluid foaming resulting in a commensurate reduction of pressure and damping of the TCC spool valve circuit's fluid pressure. Doktor A

Andy,
I've wondered why overfill would affect the RSN, if you've posted the foaming theory before I must have missed it. That theory sounds better than the "the higher level changes some pressures" comments I think I've read.

I didn't say anything, but after doing your DARF modification on my 2004 I found the tranny fluid level a bit below what I calculate as the full mark and left it that way. I'm using a DIY bottoming dipstick and figuring in your 13mm correction (actually I used 1/2") so I may be off a bit. Anyway, with your DARF conversion and my transmission level mid-range the RSN has not been a problem. There has been a very occasional slightest bit of RSN at about 38 - 40 mph on the down grade of a slight incline, but a bit of throttle makes it go away immediately as we have discussed.

Based only upon my one experience, I think transmission fluid level becomes less critical after the DARF mod. That is if it was ever that critical anyway? I'm still not convinced a 1/4 - 1/2" difference of level in a sump is a problem. If it were, why do they give us a safe range? FWIW.

I'm very happy I was included in the early DARF tests or I probably would have put off doing the mod. I think that would be a mistake. vic

Drew.eight
08-29-2010, 05:36 PM
Just completed the DARF procedure, simply amazing. Does not even seem like the same truck. Thank you Andy.



Still patiently waiting for D.A.D (maybe bump me up a few spots for the good review?? lol)

o.z.
08-31-2010, 06:01 AM
Is there anybody who did DARF, but no changes at all, or any problems after DARFing? I'm planning to order it. Thanks

abittenbinder
08-31-2010, 12:49 PM
Is there anybody who did DARF, but no changes at all, or any problems after DARFing? I'm planning to order it. Thanks

Because of overly aggressive TCC (torque converter clutch) mapping in the TCM (transmission control module) it is quite unlikely that you will experience 'no changes' after performing the DARF.

As for problems, post DARF, none have been observed by me or reported to me. Rest assured, the DARF can be easily reversed with a simple procedure, if so desired.

Complete instructions and special tooling is included in the DARF kit. Still $49.99 plus shipping and handling. Simply email me at abittenbinder@yahoo.com. for payment details.

Doktor A

Drew.eight
09-01-2010, 02:33 AM
Hey Andy,

Just wondering if you have the part number for the plate I drilled for the DARF... I was thinking about getting one and drilling the smaller hole to see if I notice any differences.

Thanks,
Drew

abittenbinder
09-01-2010, 02:50 AM
Hey Andy,

Just wondering if you have the part number for the plate I drilled for the DARF... I was thinking about getting one and drilling the smaller hole to see if I notice any differences.

Thanks,
Drew

The plate is not listed as a spare parts number.

If you must replicate the Sprinter Global Research Center testing, just silver solder your larger orifice closed and redrill with the smaller orifice. But I forewarn you, a reset of adaptation may be necessary for accurate results. Doktor A

Drew.eight
09-01-2010, 12:41 PM
The plate is not listed as a spare parts number.

If you must replicate the Sprinter Global Research Center testing, just silver solder your larger orifice closed and redrill with the smaller orifice. But I forewarn you, a reset of adaptation may be necessary for accurate results. Doktor A

Thanks Andy, I'm not trying to replicate your testing. I drive between 1500-2000 miles a week, so fuel economy is a big deal for me. After installing the DARF I noticed a decrease in MPG. According to the paperwork that came with the DARF, I should have used the smaller drill bit for "maximum fuel economy".
I'm guessing that when I get my DAD, I will be able to reset the "adaptation". Sorry, I was not trying to offend. I guess I should have explained better in my other post.

Thanks,
Drew

BBlessing
09-01-2010, 01:14 PM
does this DARF mod work on the ncv vans as well? i have had the rsn noise on downshifts since day 1. the dealer said the tranny was low on fluid and added some.

bb

sikwan
09-01-2010, 01:33 PM
He sends a 55 and a 56. I just didn't want to let the cat out of the bag..... I guess you still need to buy the kit to find out where to drill...

Oops. I thought the basic procedure had been outlined already.:doh:

So I didn't consider it a secret.:shhh:

Doesn't anyone remember this thread?

http://sprinter-source.com/forum/showthread.php?t=9305

o.z.
09-02-2010, 02:13 AM
Thanks Andy, I'm not trying to replicate your testing. I drive between 1500-2000 miles a week, so fuel economy is a big deal for me. After installing the DARF I noticed a decrease in MPG. According to the paperwork that came with the DARF, I should have used the smaller drill bit for "maximum fuel economy".
I'm guessing that when I get my DAD, I will be able to reset the "adaptation". Sorry, I was not trying to offend. I guess I should have explained better in my other post.

Thanks,
Drew

how big the difference in mpg?

abittenbinder
09-02-2010, 02:38 AM
According to the paperwork that came with the DARF, I should have used the smaller drill bit for "maximum fuel economy".
Sorry, I was not trying to offend.
Thanks,
Drew

No offense taken. I encourage your experimentation and welcome your feedback.

Are you a expediter with primarily highway driving?

During the DARF trials, owners were running with various orifice sizes but no participants switched orifice size on their vehicle. I did that here with the primary DARF test vehicle but the intent was to find optimum orifice sizing to control RSN without the counteraction effect of TCC adaptation.

Doktor A

abittenbinder
09-02-2010, 02:41 AM
does this DARF mod work on the ncv vans as well? i have had the rsn noise on downshifts since day 1. the dealer said the tranny was low on fluid and added some.
bb

I have had few reports of RSN with NCV Sprinters and because of that have not done any DARF testing with the 6cyl Sprinters.

Doktor A

Cwebsterjr68
09-02-2010, 04:54 AM
Hey Andy i have a 08 3500 Dodge 170 wb with the RSN. I wanted to try the DARF fix. Do you think it will work? It is a V6 and I had the I believe lock up solinode replaced but the RSN came back with in a couple of days. I then put in four ounces of mopar differential additive in the tranny and it went away. However it has came back. By the way I sent an email to purchase the DARF repair but haven't heard back from you. Any help will be greatly appreciated.

Thanks Charles

abittenbinder
09-02-2010, 12:51 PM
Hey Andy i have a 08 3500 Dodge 170 wb with the RSN. I wanted to try the DARF fix. Do you think it will work? It is a V6 and I had the I believe lock up solinode replaced but the RSN came back with in a couple of days. I then put in four ounces of mopar differential additive in the tranny and it went away. However it has came back. By the way I sent an email to purchase the DARF repair but haven't heard back from you. Any help will be greatly appreciated.

Thanks Charles

You sent me that e-mail yesterday. Please be patient while I decide how to proceed with the V6's.

I need a local '07-'08 with RSN complaints to conduct testing.

Doktor A

steve hatfield
09-02-2010, 07:09 PM
Assuming, we're still on this thread subject and not now addressing DARF as it may apply to 6 cylinders, I have a T1N/DARF observation to report.

Recently I took my USA '04 2500 with 60K mls, on it's post-DARF maiden post highway trip (about 150 miles each way) mostly empty as this may be important in resolving this question:

Is there any correlation between DARFing and what seems to me to be a disappearance of high speed power train torque modulation (that I experienced before DARFing at freeway speeds >75 MPH?

I ask this because, since I did a full transmission fluid change (FUCHS 236.14 spec) including TC, along with the DARF, I haven't heard or felt this familiar pitch change at higher speeds under varing inclines.

I still don't have a reliable sense of any change in fuel consumption (I also used the smaller drill bit), but as I reported earlier on the phone to Andy, any hint of previous RSN "has left the building".

Anyone???

Cwebsterjr68
09-03-2010, 03:37 AM
You sent me that e-mail yesterday. Please be patient while I decide how to proceed with the V6's.

I need a local '07-'08 with RSN complaints to conduct testing.

Doktor A

Sorry Andy,
I wish I was closer, you could use mine. My RSN is pretty consistent every 15 sec or so at 65mph. I use it for FedEx deliveries. My driver is in it 99.9% of the time. I recently drove it and experienced myself. The tranny stumbles up steep driveways and around town intermentintly also.
Thanks again,
Charles

abittenbinder
09-03-2010, 04:41 AM
Sorry Andy,
I wish I was closer, you could use mine. My RSN is pretty consistent every 15 sec or so at 65mph. I use it for FedEx deliveries. My driver is in it 99.9% of the time. I recently drove it and experienced myself. The tranny stumbles up steep driveways and around town intermentintly also.
Thanks again,
Charles

Have you ever experienced classic RSN in a 5 cyl Sprinter? Doktor A

Dougflas
09-03-2010, 10:26 AM
I drive both a 2005 3500 and 2005 2500. I have not experienced RSN that I know of. Could someone explain exactly what I should be looking for?

Cwebsterjr68
09-03-2010, 10:08 PM
Have you ever experienced classic RSN in a 5 cyl Sprinter? Doktor A

No sir I haven't, this is the first sprinter I have owned. From what has been described on this forum it sounds just like the problems others have had. It is at around 112,000 miles and the RSN started about 90k and progressivley got worse. The dealer said it was the either the torque converter or the (i believe) lock up solinode. I replaced the later(because it was cheaper) and it cured it for a couple of days. Then the dealer suggested the mopar differential additive which cured it right away, however it has returned and im not sure if i should keep adding the 4oz additive. i will have to drain off some tranny fluid to keep adding.

Charles

Aqua Puttana
09-03-2010, 11:09 PM
I drive both a 2005 3500 and 2005 2500. I have not experienced RSN that I know of. Could someone explain exactly what I should be looking for?

So you don't feel ignored.

If you do a search from the blue bar above there are quite few hits.

I started this thread. Doktor A describes the symptoms a bit into the thread.

Rumble Strip Noise Transmission Drive Train Shudder
http://sprinter-source.com/forum/showthread.php?t=5027&highlight=rsn+shudder

Hope this does some good. vic

abittenbinder
09-07-2010, 04:21 AM
No sir I haven't, this is the first sprinter I have owned. From what has been described on this forum it sounds just like the problems others have had. It is at around 112,000 miles and the RSN started about 90k and progressivley got worse. The dealer said it was the either the torque converter or the (i believe) lock up solinode. I replaced the later(because it was cheaper) and it cured it for a couple of days. Then the dealer suggested the mopar differential additive which cured it right away, however it has returned and im not sure if i should keep adding the 4oz additive. i will have to drain off some tranny fluid to keep adding.

Charles

Has your dealer tried a 'reset of transmission adaptations' on your '07-'08? Doktor A

Cwebsterjr68
09-11-2010, 05:05 AM
Has your dealer tried a 'reset of transmission adaptations' on your '07-'08? Doktor A

No they haven't. I can talk to them.

Charles

hulagun
12-29-2012, 02:54 PM
Sorry.

I did the larger, the .056, and did not notice any real difference in mileage on my 1100 mile journey recently.



#56 drill bit = 0.0465" or 1.181 mm

#55 drill bit = 0.052" or 1.3208 mm

Smaller number = larger hole

hulagun
12-29-2012, 03:39 PM
Hi guys and Andy,

I experienced a situation recently with my T1N, it started up and drove OK but in a few minutes as traffic began moving faster, upshifts were VERY HARD. Because I had entered slow-moving rush hour traffic on the highway, it took about 5-10 minutes to pull over and just got gradually worse. Finally I found a wide spot, pulled off, shut off the motor, and waited 60 seconds. Then restarted and put it in gear and proceeded. The behaviour had disappeared and has not returned since. Seems like a good time to do the trans fluid service!

Last summer I purchased a complete kit for the trans fluid change, so plan to do that as soon as the rain here stops. Because my van occasionally experiences mild RSN at low speeds, I'd sure like to also do the DARF mod (Thanks Dr. A!) while I'm under the van. Reading up on the DARF, I found that I already own the necessary tools (micro drill collet and #56 bit) to drill the valve body end plate.

I have been looking for work for weeks, so $$ are in short supply, and we are in super frugal mode. So I'd like to check if I can confidently proceed with the DARF mod using only the info already generously posted by Dr. A? Or is ordering the kit necessary to guarantee success?

I'm willing to pay Dr A. for the kit, just for the "special instructions", if that is the right thing to do here. What to do? :thinking:

Ivan

abittenbinder
12-29-2012, 04:54 PM
Hi guys and Andy,


I have been looking for work for weeks, so $$ are in short supply, and we are in super frugal mode. So I'd like to check if I can confidently proceed with the DARF mod using only the info already generously posted by Dr. A? Or is ordering the kit necessary to guarantee success?

I'm willing to pay Dr A. for the kit, just for the "special instructions", if that is the right thing to do here. What to do? :thinking:

Ivan

Ivan, I appreciate you asking. Contact me directly at my e-mail address.

People who contact me directly for purchase of the DARF kit are asked a series of questions before they can purchase the kit.

About 80% are told they should NOT perform the 'fix' and are not sold the kit.

So it should be clear that this is not about a revenue stream but about making sure only the people who may benefit, perform the fix.

I am very disappointed that someone has posted installation info (on a independent site) and a link to it on this site, without understanding the consequences.

Doktor A

hulagun
12-30-2012, 05:03 PM
Hi Doktor A -

I sent you email at abittenbender@yahoo.com. Hope that is correct. I know you are busy and look forward to hearing back when you have time. I'm eager to see if the DARF fix will benefit my van, and standing by to change my ATF as soon as you advise.

To clarify (for others) I read some basic info here on Sprinter Forum. I have not seen any DARF installation info from any other site.

Thanks again,
Ivan

Ivan, I appreciate you asking. Contact me directly at my e-mail address.

People who contact me directly for purchase of the DARF kit are asked a series of questions before they can purchase the kit.

About 80% are told they should NOT perform the 'fix' and are not sold the kit.

So it should be clear that this is not about a revenue stream but about making sure only the people who may benefit, perform the fix.

I am very disappointed that someone has posted installation info (on a independent site) and a link to it on this site, without understanding the consequences.

Doktor A