Shudder in 5th ... sometimes????

[Burla]

If it were plugs you should get CEL. If it doesnt do it in TH it is low rpm shudder most likely. It only happens in 5th or maybe 4th or 6th because those are your longest gears as in the widest rpm range, so you likely don't even get in low rpm's enough to make it shudder in 1,2,3. When you say you changed to redline you mean in engine or transmission? If in TH it takes away your shudder, this is a transmission issue.

 

[Jwrigh12]

Redline engine oil. Not transmission. Transmission oil drain and fill with new oil pan is also on the list....


It's a long list

 

[Jwrigh12]

Wait I'm confused. I reread your post @Burla. You said if it doesnt do it in TH, it's likely low rom shudder. Then said if TH takes it away, it's a transmission issue. Can you clarify?

 

[Burla]

Yes that's the same thing, TH is a transmission aide, it changes the shift points to take away low rpm's as low rpm's are bad for towing. Low rpm shudder is a very common thing, it is an early warning symptom that can be fixed with smoke and mirrors and be fine, meaning you don't have to pull the tranny apart. If it doesnt shudder in TH, well then drive in TH, I did that for 7 years and fixed my low rpm shudder. Now, I have the rfe, so when I went to redline c+ my shudder was gone, this really isnt available to you with the 8 speed, it is a risk running d^ in that transmission, so I dont recommend redline in the 8 speed. Now, many people run it without issue, but trusted members have had some issues, so I would not risk it for this.

Smoke and mirrors in this case, transmission cleaners such as autorx, additives such as lubegard shudder fix, or mechanical as in drive in tow haul. Because the 8 speed operates at high temps, the best move is TH, the second best would be a cleaner, the most risky is a lubrication strategy that adds something different.

 

[BenWade]

Yes that's the same thing, TH is a transmission aide, it changes the shift points to take away low rpm's as low rpm's are bad for towing. Low rpm shudder is a very common thing, it is an early warning symptom that can be fixed with smoke and mirrors and be fine, meaning you don't have to pull the tranny apart. If it doesnt shudder in TH, well then drive in TH, I did that for 7 years and fixed my low rpm shudder. Now, I have the rfe, so when I went to redline c+ my shudder was gone, this really isnt available to you with the 8 speed, it is a risk running d^ in that transmission, so I dont recommend redline in the 8 speed. Now, many people run it without issue, but trusted members have had some issues, so I would not risk it for this.

Smoke and mirrors in this case, transmission cleaners such as autorx, additives such as lubegard shudder fix, or mechanical as in drive in tow haul. Because the 8 speed operates at high temps, the best move is TH, the second best would be a cleaner, the most risky is a lubrication strategy that adds something different.

Exactly right. The higher operating temps of the ZFs causes a slick glaze to form on the clutch plates. This is why when at low rpms the shudder is more noticeable because the clutch plates aren't "grabbing". When under higher RPMs or in tow haul mode there is more force being applied allowing the plates to "grab"

 

[Dusty]

I'm not yet convinced this is a transmission problem. Are there any codes stored? I'd have the clutch fills and clutch indexes checked before proclaiming a tranny problem.

If I read the OP first post the engine had 163K on it? I'd change out the plugs before going on to more diagnostics.

Regards,
Dusty
2019 Ram 1500 Billet Silver Laramie Quad Cab 2WD, 5.7 Hemi, 8HP75, 3.21 axle, 33-gallon fuel tank, 18” wheels. Build Date: 3 June 2018. Now at 98443 miles.

 

[Marshall]

I would think with that mileage a transmission oil filter change would be a first move rather then changing plugs. I have not heard anyone say it was changed.

 

[Jwrigh12]

Ok so its been a minute since I've had a chance to get on here! Here's the update.

1. Ive been driving it in Tow/Haul since I posted this thread. TH mode seems to make it a little bit better, but not all the way. I would say that TH has 10-20% the shudder that normal driving has. Again mainly in 5th - that being said, either Im paying more attention, or the symptoms are spreading, as outside of TH mode it seems to be in 3-5 now. Less in the other gears, but still present.
2. I got the truck at 143k - and the only service history I can confirm is a water pump about 10k prior to that. @Dusty As far as plugs go, I have no idea. @Marshall same goes for fluid and filter change. Plugs have been on my list, just havent had the time recently. For that matter.... a trans fluid change and thermostat mod have also been on the list too...
3. No codes of any kind have been thrown recently. As a matter of fact, the only codes Ive ever gotten are codes for fuel tank voltage out of range (over a year and a half ago that went away on its own), and a code for my 3 way coolant valve. The valve body is still there and plugged in to avoid throwing a code (most of the time), but the actual coolant lines are hooked up to a 3 way pipe fitting and always open.

So. I did go to the store yesterday and got two tubes of shudder fixx - transmission was too hot today after dropping the kids off at school to put it in though... so that'll have to wait for the weekend.

Any thoughts/suggestions as to some next steps? Shudder fixx right away? Would a drain/fill be beneficial? I think I saw on some other thread something about a flush product designed to clean off the glaze that @BenWade was mentioning. Any ideas?

 

[Marshall]

I have never played with the 8 speed transmission, I would not add anything, but some of the transmission guys will have better info
Last one I did was a 727 in my 1968 Imperial

 

[BenWade]

I had a transmission shop recommend the BG Products transmission flush and clean. They recommend every two years or 30k miles