Yet another 48re question

[BigFish]

I'm trying to do everything I can to avoid throwing my hands up taking this truck to the trans shop.
2006, 2500 mega cab. 48re was not feeling the way I'd like when throttle was applied. When driving from a stop, in 1st, 2nd, and 3rd before tc locks up, it felt like I could power through the trans with enough throttle. Tach would jump to 2200-2600 under 3/4 throttle or so, and rpm would settle there for acceleration most times. Add more skinny pedal and rpm would jump to 3k without corresponding increase in acceleration. Once tc locks it feels pretty solid. Shifts were there but almost imperceptible, just greased from one gear to the next. Talked to some members here and couldn't solve the issue.
As a hail Mary, since i already had the parts, I went ahead and installed a superior shift kit, sonnax billet accumulator and servo/cover, aftermarket gov pressure sensor/transducer, new filter and roughly 3 gallons of new fluid.
As of now, the shifts feel alot more firm, but minimal rpm drop upon shifts, and behaves almost the same under 3/4 throttle. Will jump to 2200 or so and hold about there under 3/4 throttle and accelerate, but still feels like it's losing a ton of torque in the trans. If I increase throttle beyond 3/4 or so, the tach still jumps up to 3k or limiter and accelerates about the same as it does at 3/4 throttle... maybe a little more acceleration but not by much. Again once tc locks it feels better.
Smarty touch transmission pressure reads 0-5 psi at idle whether in P, D, R, 1, 2. Pressure rises under acceleration but only to about 30-50 psi then jumps to a max of 90ish psi once tc locks under acceleration. I have not seen over 90ish psi even with tc locked and heavy throttle.
Does anyone have any ideas for me as a diagnosis? I was thinking maybe the TC is the issue due to it behaving in lock up but not so much before lockup, but I'm honestly pretty lost and could be very wrong. Several members here have been a great help to me figuring out other issues so hopefully someone has an idea.
Someone able to help a guy out?

 

[Ozymandias]

More then likely your TC is toast.
Get a nice triple-disc from Suncoast or Goerend.
This two company's run a damper system so you don't harm the transmission locking up.
Don't go low stall if you pull trailer.

 

[BigFish]

Thanks for the input ozy, you've been hugely helpful a time or two.
Not to disagree with you, but simply for my own understanding and education, can you explain what in my description specifically leads you to that conclusion vs any others?
Been a long ride getting this thing sorted, but trying to learn everything I can along the way.

 

[Ozymandias]

Sounds like you have a ballooned converter that can't bring the power through anymore. It happens often to the factory converter as it is a weak design.
The 2200rpm sounds reasonable for factory, but then you can turn it through without gaining momentum up to the red line says the converter is likely toast as this shouldn't happen.
Would your Trans be slipping the same amount it would burn the clutches and bands almost instantly and you would see it in the Trans fluid.
A slipping converter doesn't stain the fluid.

 

[petersonj]

Don't go low stall if you pull trailer.

Just curious, as I had never heard this before - why not use a low-stall converter if you pull a trailer?

- John

 

[Ozymandias]

It keeps the turbo from spooling, which is a huge deal breaker if you want to start from a stop sign.

I have low stall and even for my 13k lbs and 4.10 axle it sometimes is a nuisance.
I had it installed after a long conversation with Suncoast, weighing the pros and cons for what I use the vehicle.
The low stall is good for maneuvering off road in low range.

 

[BigFish]

Sounds like you have a ballooned converter that can't bring the power through anymore. It happens often to the factory converter as it is a weak design.
The 2200rpm sounds reasonable for factory, but then you can turn it through without gaining momentum up to the red line says the converter is likely toast as this shouldn't happen.
Would your Trans be slipping the same amount it would burn the clutches and bands almost instantly and you would see it in the Trans fluid.
A slipping converter doesn't stain the fluid.

Would the ballooned converter theory still apply even though it's holding ok once it locks up? Is this the case because the fluid coupling and the lockup ar3 separate mechanisms within the TC?

 

[petersonj]

It keeps the turbo from spooling, which is a huge deal breaker if you want to start from a stop sign.

What engine rpm do you consider a low stall speed?

My brother-in-law has a 2001 truck with a modified transmission which includes a low stall speed converter (around 1,850 engine rpm). His truck is still stock with exception to the transmission. His truck has 3.55 gears.

I called him and asked if he has any issues getting his rig moving when pulling his fifth trailer of 14,000 lbs moving. He said that when he enters the roadway from his driveway (uphill slope), he notices a small delay in getting the rig moving - similar to what you pointed out. But, other than that, he says the low stall speed converter is better in every other way. He said that he would definitely would not go back to an OEM stall speed converter.

I know that everyone has different experiences, but I was surprised at your observation - and, of course, I value your opinion.

- John

 

[Ozymandias]

Would the ballooned converter theory still apply even though it's holding ok once it locks up? Is this the case because the fluid coupling and the lockup ar3 separate mechanisms within the TC?

Absolutely, the clutch will hold where the rotor and stator won't do it anymore.

 

[Ozymandias]

What engine rpm do you consider a low stall speed?

My brother-in-law has a 2001 truck with a modified transmission which includes a low stall speed converter (around 1,850 engine rpm). His truck is still stock with exception to the transmission. His truck has 3.55 gears.

I called him and asked if he has any issues getting his rig moving when pulling his fifth trailer of 14,000 lbs moving. He said that when he enters the roadway from his driveway (uphill slope), he notices a small delay in getting the rig moving - similar to what you pointed out. But, other than that, he says the low stall speed converter is better in every other way. He said that he would definitely would not go back to an OEM stall speed converter.

I know that everyone has different experiences, but I was surprised at your observation - and, of course, I value your opinion.

- John

There are options between the sluggish factory Converter and a true low stall.

Just today it caught me again turning into a busy highway, nothing but black smoke and to little movement. Letting go and rolling into the throttle helps then but sometimes that isn't an option.

Truth spoken is a low stall converter turns the truck into a dog.
Once it's moving you won't notice it and it is great all around, but moving from a dead stop is a pain if you demand a speedy departure. Not fun at all.

But also I wouldn't go back to stock.

It's all about making an educated decision before buying.
To me at Suncoast it was the first time that someone has spoken to me about the cons of low stall converter.
There is probably a reason why they aren't fitted from the factory right away.

 

[Ozymandias]

For my friend with the 98.5 we got a triple Disc enhanced stall from Goerend after I had the conversation with them about which one to choose.

 

[Ozymandias]

But also, I wouldn't go out and just buy a converter because of what I said.
I think a Trans mechanic should at least do a test drive with the vehicle as is and give his opinion about it.

 

[BigFish]

But also, I wouldn't go out and just buy a converter because of what I said.
I think a Trans mechanic should at least do a test drive with the vehicle as is and give his opinion about it.

I appreciate the input. I'm going to let this thread ride for a while and see if I get any more replies and get a bit of a consensus. I'm thinking it'll end up being a trip to the shop and ordering a tc. I don't think I have the time or the driveway space to be dropping a trans and installing a new TC.

 

[promisedland]

Hope you find answers.
Ozy, I'm curious what stall speed TC you have? My 900/400 georend is higher stall then I'd like, mine is 130rpms lower then stock according to Dave at georend. (He compared at 500'#s of torque)
62mm garret ball-bearing turbo.
Starting 20,000# gross up a grade is a chore... high rpms till lockup.. Definitely better then oem though.

 

[Ozymandias]

I can only guess at the moment because we didn't talk numbers down at SunCoast, I'd say 1800rpm also from how it feels.
Just slightly below from what the Turbo really starts to spool.
It's the whole Stage #3 package from SunCoast I've in my truck.

 

[Ozymandias]

If I have to choose between the Goerend and the SunCoast I'd go with Goerend because the one I put into my friends 98.5 works extremely well.

https://goerend.com/goerend-47-48re-triple-disc-converter/

 

[sag2]

Ozy is correct. If it was a clutch or band slipping it would smoke them in a hurry. The only other place to slip besides a clutch/band is in the converter. You can make a lockup switch to lock the converter and that would confirm the problem. You might also be able to monitor the converter cooler out line. If the converter is slipping excessively it will raise the fluid temp very quickly and much higher than normal.
Side note, if the converter is ballooned it usually distorts the front cover and also can cause the lockup clutch to not fully lock, but that should result in the same clutch material pieces and burned fluid in the pan.