would you add an additional transmission cooler?

Maybe I missed it … but how's the engine cooling overall ?
Also thought Snag had an interesting comment on an oil cooler … the more things cooling well the better …
 
Originally Posted by 4WD
Maybe I missed it … but how's the engine cooling overall ?
Also thought Snag had an interesting comment on an oil cooler … the more things cooling well the better …




its pretty good. the truck has 2 electric rad fans. if i work it hard and slow down like stop and go traffic the temp climbs a bit but it drops pretty quickly when i hear the fans come on.

the engine oil cooler is interesting. I'll have to read up on it and see what my options are
 
Originally Posted by MrTruckDriver
im not sure if it has the tow package. it came stock with a little trans cooler as well as a power steering oil cooler. no engine oil cooler though. with my current set up ive never gotten it up to 190 running empty, even pulling my trailer on the highway temps would be in the 160s and hit 180 while climbing hills. when i made it hit 190 i wash pushing it. low speed on a 10 percent grade for about 15 min.

its probably outdated information but ive read keep an automatic transmission under 180 if you want it to last.


190f is a cakewalk for for Dexron VI as it is much more temperature stable than Dexron III. Short spikes up to 230f like when pulling a pass are not a problem, either. GM says 260f is safe for short periods of time. You've got the transmission cooling situation well covered.
 
Originally Posted by MrTruckDriver

it looks like the 4l65 was paired with the 60L vortec only.

i could have my specs wrong on the hill. it was heading up toward a ski hill though, i drove up it to see if the truck could maintain 180 i chickened out at 190. im not sure what the deal breaker temp for the trans and dexron vi is.


That is correct, The 4L65E/4L70E was only paired with LQ4/LQ9/LS2 6 litre engines. People have claimed to have "Special ordered" a 65E behind 5.3L's but I've never seen a SPID to prove it.
RPO for a 60E is M30 & M32 is for a 65E.

4L65E's are just as susceptible to failure as a 60E, Even more so in my opinion with their thinner 3-4 Clutches. The main upgrade was 5 Pinion Carriers vs 4 Pinion Carriers found in 60E's......But there is nothing inherently wrong with 4 Pinion Carriers until you get way outside the GVWR of the truck.

I highly recommend turning off the Torque Converter Clutch PWM apply via tuning software like HPtuners, This will prolong the life of the Converter Clutch & The Converter Clutch Regulator Valve bore in the valve body.
*TransGo has a drop in TCC Regulator Valve that does this Mechanically/Hydraulically, But requires buying their shift kit (SK-4L60E or 4L60E-HD2) & dropping the valve body.

If dropping the Valve Body & Removing the 2nd/4th Servos isn't out of your wheelhouse.....There are some more upgrades to prolong the transmissions life expectancy. Let me know....

Intermediate spikes in temperature up to 220°-230° while pulling steep grades at low speeds is to be expected.
 
that answers my question regarding another trans cooler.

I've been keeping it out of D when pulling i thought the converter didn't lock up in 3rd?

I'll read up on software, I hadn't thought of what any sort of tuning could do for my situation.

I don't know if im good enough to drop a valve body but i am interested in doing transmission work. it will involve some research on my part.
 
It does lock-up in D3, Using Tow/Haul will change Apply/Release vs Speed vs TPS. In fact there is no D3 table (Meaning the D4 & D3 TCC apply/release tables are identical).....You're just locking out 4th/OD.
This is a 2008 Silverado 5.3L/4L60E with 3.73 gears.....Yours will differ a little!

Normal TCC Apply/Release vs Speed vs TPS....
[Linked Image from i.imgur.com]
 
The above tables do not mean it will lock-up in 3rd then shift to 4th while in D4!! You have to compares these to Shift Speed tables.......

As you can see.....The 3-4 shift is commanded before the 3rd TCC Apply speed threshold is met until it gets over 100 mph, Your truck is governed to @ 98 mph.

[Linked Image from i.imgur.com]
 
Originally Posted by MrTruckDriver
thanks i didn't realise the converter locks up so often. also looks like pretty friendly software. would it let me disable the converter lockup just in tow haul mode?

I'm not sure why you would want to disable lockup. Locked means no slippage and thus no heat generation.
 
Originally Posted by MrTruckDriver
it sounds like towing is hard on the tc clutch.

Yes, locking while under load will be, especially if rpm is low--the bigger the speed differential between input and output the more wear while it locks. I believe that is why clinebarger recommends turning off PWM--they control the rate of lockup so as to soften the action and thus reduce or remove any "shifting" jarring that you could feel. I suspect in tow mode it reduces the PWM time for faster lockup.

Here's the thing. In my truck I've always just forced a downshift before it was needed. If I thought it'd be required at the base of the hill, I'd just force. But. It's not like it can't handle the "abuse". It's meant to shift under load, at least a number of times, otherwise it wouldn't make it out of warranty, and no OEM wants to deal with that. So if you find it occasionally shifting and you didn't get you foot off the throttle, it's ok, it's meant to handle that. You may be adding longevity by forcing the downshift early but it's by no means required.

Disabling the TC lockup would make the clutch last longer but then you have to deal with additional heat buildup in the transmission--which the cooler can handle, but now it sounds like trading TC lifespan for the life of the rest of the transmission.
 
Originally Posted by MrTruckDriver
thanks i didn't realise the converter locks up so often. also looks like pretty friendly software. would it let me disable the converter lockup just in tow haul mode?


You can tune it that way by maxing (318) all the cells in the Pattern "A" TCC Apply/Release vs Speed vs TPS, But like Supton said.....That would be counterproductive to keeping your trans cool.

Originally Posted by MrTruckDriver
it sounds like towing is hard on the tc clutch.


Not as much as the PWM apply, The TMBX 300mm converter used in late 4L60E's is actually a very well built unit....Tuning out the PWM apply could very well extend it's life to EOL of the transmission.

Doing this is very simple.....Set all cells in the Minimum TCC Duty Cycle vs Line Pressure vs Trans Temp to 90% & Set all the cells in the Maximum TCC Duty Cycle vs Line Pressure vs Trans Temp to 99%
There has to be a differential between minimum & maximum or it does weird things!! 90% will still fully lock the converter clutch.

Factory converter clutch pistons have damper springs so it won't be very harsh at all. The Billet front/Billet TCC piston stall converter in my Camaro hits pretty hard.

Here's a stock Minimum TCC Duty Cycle table...
[Linked Image from i.imgur.com]
 
that's interesting, I didn't even know the pwm was a thing. it sounds like changing those values reduces clutch slip in the tcc?
I'll need to take some time and lean more about the system.

thank you for all this advice.
 
Back
Top