8HP70 Trans shudder, getting worse, no codes, how to diagnose ?

TheEnder · Feb 2, 2021

TheEnder said:
A few questions which would help me:

What temp is the tranny at when this issue is faced?
Does it happen cold when the vehicle is loaded up?
Are you running it in tow/haul when you have this issue?
Do you notice any sluggishness with the vehicle? As in the engine doesn’t seem to be performing as well as it should?

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Forgot the most important one - What are the RPMs doing when this happens? Are they fluctuating or staying still?

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Tach_tech · Feb 2, 2021

TheEnder said:
This really only applies to the 6 speed - 8 speeds don’t go off of CVIs, they go off of fill-time.

Not much different i know, but with shuddering, i’d expect an eaten up torque converter.

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Honestly we use the two terms with both trannies. Everyone knows what you means.

The 8 speeds CVIs/fill counters etc are very picky about engine rpm/load/input torque/vehicle speed etc. If you’re not driving straight on a flat road it can take well over an hour to get enough valid fills in order to be stored in the memory.

RedSRT4Me · Feb 2, 2021

TheEnder said:
A few questions which would help me:

What temp is the tranny at when this issue is faced?
Does it happen cold when the vehicle is loaded up?
Are you running it in tow/haul when you have this issue?
Do you notice any sluggishness with the vehicle? As in the engine doesn’t seem to be performing as well as it should?

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I can answer some questions as I experience this every now and again.

My theory is driving style and temperature. I drive aggressive as well. I will only get this shutter 1st thing in the morning on the very 1st one- two shift no matter the throttle load greater than 10%. For those with throttle manipulators this is probably getting multiplied for you almost like a straight bronco buck.

Only 1st drive, only cold. Some weeks AZ is 80 degrees and it won't do it. Some weeks it's 40 out and I can get the truck to do it repeatable once a day. Just that 1st one-two shift of the trans temp isn't warm yet. Guessing >100° F or 38° C rounded up for our Canuck Brothers.

I never use tow/haul for the most part.

I would never classify my truck in the sluggish category.

TheEnder · Feb 2, 2021

Tach_tech said:
Honestly we use the two terms with both trannies. Everyone knows what you means.

The 8 speeds CVIs/fill counters etc are very picky about engine rpm/load/input torque/vehicle speed etc. If you’re not driving straight on a flat road it can take well over an hour to get enough valid fills in order to be stored in the memory.

Didnt know that. Good to know for the future.

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Tach_tech · Feb 2, 2021

TheEnder said:
It’s miles.

With the RFE, after a quicklearn, it’s advised to not bring the vehicle past a 50° throttle angle because the TCM will not learn past that for the first 500 mi.

Also with the RFE, it has to be over 110°F for it to start to learn adaptives. The 8 speed needs to be brought up to operating temp for it to learn adaptives, and the only way to do a “quicklearn” with the 8 speed is to have the dealer do it. AlfaOBD won’t do it from what i hear, but i’m not willing to find out.

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It depends which 8 speed you have, the 45 has a quick learn procedure with a scan tool. The 70 doesn’t have one, it’s done by a drive learn. Kind of a pain in the ass procedure to perform.

TheEnder · Feb 2, 2021

Tach_tech said:
It depends which 8 speed you have, the 45 has a quick learn procedure with a scan tool. The 70 doesn’t have one, it’s done by a drive learn. Kind of a pain in the ass procedure to perform.

More great information. I thought it was universal for all models.

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Tach_tech · Feb 2, 2021

TheEnder said:
More great information. I thought it was universal for all models.

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You would think so ya lol, but for whatever reason it isn’t. I think it has to do with wether it’s ZF built or FCA built. At first FCA was allowed to build the 8hp45 as the 845RE, which had a quick learn. While the 8HP70 was ZF only and had no quick learn. I’m not a 100% but I think some of the newer 8HP70/75 are able to do a quick learn.

RedSRT4Me · Feb 2, 2021

TheEnder said:
Forgot the most important one - What are the RPMs doing when this happens? Are they fluctuating or staying still?

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For me I can guess this occurs above 1000 but below 1500 ish maybe? Definitely below 2000.

I'll have to pay more attention.

Uncle Damo · Feb 3, 2021

TheEnder said:
A few questions which would help me:

What temp is the tranny at when this issue is faced?
Does it happen cold when the vehicle is loaded up?
Are you running it in tow/haul when you have this issue?
Do you notice any sluggishness with the vehicle? As in the engine doesn’t seem to be performing as well as it should?

Sent from my iPhone using Tapatalk

It's all very fresh in my mind from towing this past weekend, and then driving the truck empty after dropping the trailer.

This behavior happens when cold or hot, from the very first 1-2 shift and the same 3 hours into a drive. I see tranny temps typically between 180 - 200 when towing, sometimes low 200's when pulling a grade, as I remember.

Happens whether tow/haul mode is on or off, or if I shift manually using the buttons on the wheel.

No sluggishness, engine is running really well at all RPM's. No unexpected fluctuations, just normal increasing RPM's as speed increases.

*Updated after test drive this morning, not towing, but starting on steep hill* - The shudder is happening between about 2200 - 2600 RPM's, just before shift from 1-2. It gets stronger as RPMs increase before shift point.

RedSRT4Me · Feb 3, 2021

Ok today I was paying attention.

Mine starts at just above 2000, jumps to about 2500+ or - then drops back to 2000 then continues like normal.

Trans temp was 75° F. Outside temp is 80F

RamCares · Feb 4, 2021

misfit77 said:
Is Ramcares still a thing here?

They might be able to help.

Hi @misfit77 -- YES! Our @RamCares team is still very much a thing. Thank you for directly tagging us and bringing this to our attention!

@Uncle Damo,

We're super sorry to hear about the experience you've been having with your Ram dealer recently. If you're unsatisfied with your current dealer's servicings, we kindly recommend visiting a different dealer nearby for a second opinion. For your convenience, head over to https://www.ramtrucks.com/find-dealer.html to find your nearest Ram dealer. You can modify your search based off of location and services needed. Once you decide which dealership you would like to move forward with, please feel free to follow up with our team via private messages and we can certainly investigate your situation further! Thanks a ton.

Courtney
Ram Cares

Uncle Damo · Feb 4, 2021

RamCares said:
Hi @misfit77 -- YES! Our @RamCares team is still very much a thing. Thank you for directly tagging us and bringing this to our attention!

@Uncle Damo,

We're super sorry to hear about the experience you've been having with your Ram dealer recently. If you're unsatisfied with your current dealer's servicings, we kindly recommend visiting a different dealer nearby for a second opinion. For your convenience, head over to https://www.ramtrucks.com/find-dealer.html to find your nearest Ram dealer. You can modify your search based off of location and services needed. Once you decide which dealership you would like to move forward with, please feel free to follow up with our team via private messages and we can certainly investigate your situation further! Thanks a ton.

Courtney
Ram Cares

Thank you @RamCares I will inquire with the dealer where I purchased the truck rather than my closest dealer and see what I get.

Big red 15 · Feb 8, 2021

My 6spd in my 2500 was shuddering. The dealer pulled the pan and found clutch parts along with burnt fluid. Just under 50k.

lipidboy · Feb 8, 2021

My 2015 2wd Hemi 8 speed had exactly the same issue after 39,000 gently driven miles. Eventually did throw a code, dealer disassembled and found several bad clutches. Thank goodness I bought the lifetime FCA warranty! Would have cost nearly 8,000$. FCA warranteed and replaced with a new trans. Now at 92,000, no further issues. Note: I had pulled an enclosed 5,000 pound toy trailer for around 3,000 easy highway miles prior to the issue. Sold the trailer and havent towed since...BTW, I HIGHLY RECOMMEND the James dealership in Hampshire, Illinois! Amazing group of people doing ethical business for many decades,

Uncle Damo · Feb 8, 2021

The dealer where I bought it in San Juan Capistrano was very helpful. The Service Mgr took a drive with me this morning with the trailer hooked up and I'll be taking in for an appointment with their transmission specialist soon. Will report back on the outcome.

Uncle Damo · Mar 15, 2021

It wasn't a transmission issue after all. The dealer couldn't reproduce the issue without the trailer hitched up to provide real load, so I got creative and put a GoPro and light in different spots under the truck to see if it was something else, and it certainly is. It is worth saying the dealer was working with me and I have an appointment to bring the truck and trailer in to reproduce the issue, maybe not necessary now.

I don't know if this is a balance issue, or bad support bearing, but I'll let them decide with this new information.

crash68 · Mar 15, 2021

Uncle Damo said:
I don't know if this is a balance issue, or bad support bearing, but I'll let them decide with this new information.

That looks like the mid-shaft bearing is bad. That bearing should keep the driveshaft stable, if you can wiggle the driveshaft around the bearing is bad.

Curt Gobbell · Aug 16, 2021

Uncle Damo, did you get a definitive answer on your shudder? carrier bearing, trans or torque converter?

Uncle Damo · Aug 16, 2021

Dealer ended up replacing the driveshaft and center support bearing, and shimmed the support bearing down about 3/4" to correct the driveline angle. All but the shim kit was paid for by extended warranty. My truck has a 1.5" poly spacer lift and air bags in the back, so it's effectively lifted about 2.5" and runs at that level when towing. I've since then towed over 2k miles including some very steep hairpin switchbacks in the Sierras and the problem is solved.

Curt Gobbell · Aug 16, 2021

Uncle Damo, thanks for the reply. My truck has the short bed, so I do not have a carrier/support bearing on my driveshaft.

8HP70 Trans shudder, getting worse, no codes, how to diagnose ?

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