stock tranny cooler and towing

[fooldancing]

I am wondering if I need to add a bigger or just add another tranny cooler for towing a travel trailer? I want to do things right so I don't have a costly repair at the end of the year. I maybe towing the trailer once and month at the most 250 miles one way. I do have a good brake controller and I need and I am planning on a weight distribution hitch.

Thanks for the help and info in advance,
Matt M.

[muddy tires]

GM says that you can attain maximum tow ratings as equiped from the factory (small trannie cooler integrated with rad). Most of us who tow big boats or travel trailers have added additional coolers.

Anybody have any recommendations on temperature guages? Is it a do-it-yourself install? Where did you mount the sender and how did you mount the guage?

[brettster98]

fist of how bigg is the trailer ( weight) most importantly is that you can tow any thing with any thing but stopping in a hurry is most scary. more info on what oyu have is helpful...

[ScarabEpic22]

Get the biggest one you can fit into the space between the radiator and the grille, I have one that I bought for $45 last year, and coupled with a fluid flush my trans temps stay in the 130F range in 3 (TCC completely locked up, slip <5rpm) or 170F in 4th with the TCC locked up. GM uses a special controller that allows for completely lockup in 3rd gear yet allows a specificed amount of slippage in 4th. Works fine, but generates a little more heat.

It is worth the $50-60 for a DIY or ~$100 for a professional install, get the cooler and about a qt or two of ATF and a Saturday afternoon is all it takes.

[jay boy]

Erik, can the truck be reprogramed to full lockup in 4th? I only tow in third but would like to know how this works. Is the tcc on and off in 3rd and PWM in 4th? how about 2nd? Please let me know. Fooldansing get a cooler! No one has ever regretted putting one on but some have regretted not putting on a cooler Thanks Jay

[MTPockets]

Jay, the TC will lock in 3rd and 4th on the 4L60E with OEM programming.

Joel

[ScarabEpic22]

Erik, can the truck be reprogramed to full lockup in 4th? I only tow in third but would like to know how this works. Is the tcc on and off in 3rd and PWM in 4th? how about 2nd? Please let me know. Fooldansing get a cooler! No one has ever regretted putting one on but some have regretted not putting on a cooler Thanks Jay

The TC is still PWM in 3, however it definitely commands 100% lockup from the logs Ive taken on my 02. That translates to very little slippage and therefore much less heat buildup. In D (or 4th), the PWM system can command something like 95% lockup, so there is always some slippage occuring. I think the GM mentality behind this is the transition from lockup to non-lockup in 4th can be smoothed much better and then you do not feel it (no big shift feel). I can attest to this as when I had my Transgo shift kit it would feel like I was upshifting again when the TC engaged in 4th.

I am pretty sure there is no way to program the transmission to lockup 100% in 4th without installing a shift kit that converts the TCC function from a PWM system to a on/off system. I would be hesitant to do this as my shift kit just messed everything up. If you do have it professionally installed.

2nd gear the TC is programmed never to come on. The newest update for EFILive has these tables that it appears I could command lockup in 2nd, I have no reason to do this but I might try it just for kicks, and if I do I will report back.

Get a trans cooler and get a trans temp guage. Monitor the temps, but you should be okay as long as the trans temp doesnt rise above ~210-230F (my estimate, the pros can probably tell you better that I can) you should be okay in D. Personally, after all the junk Ive just gone through, I will stick to 3 unless Im coasting downhill or am on basically flat ground.

[jay boy]

Thanks Erik! Now I understand how it works. The reason I asked about 2nd gear is my old 90 surburan with a 700r4 would lock up in 2nd gear! I don't think that I will change to an on /off system for tcc control. Keep in mind that I have 3.42 gears so I can easilly hit 90mph in 2nd if I wanted to.[ this is only 10mph less than my max towing speed of 100mph LOL] Jay

[MTPockets]

Good info as usual Erik! IMO, one thing that is nice with the PWM 'lockup' is, you can make a pretty decent throttle change and it doesn't even feel like it comes out of lockup. Atleast this is the case with my 2005. The old on/off style lockups drive me nuts!:crazy: On my Ford brownstar minivan, the slightest throttle change bangs it out of, and back into lockup! It's REALLY annoying if you let someone drive who is not steady on the go pedal. Man I hate that.:duh: Oh... back to the OP. YES! get an auxillary ATF cooler if you will be doing regular towing. Any is better than none for regular heavy towing.

Joel

[ScarabEpic22]

Good info as usual Erik! IMO, one thing that is nice with the PWM 'lockup' is, you can make a pretty decent throttle change and it doesn't even feel like it comes out of lockup. At least this is the case with my 2005. The old on/off style lockups drive me nuts!:crazy: On my Ford brownstar minivan, the slightest throttle change bangs it out of, and back into lockup! It's REALLY annoying if you let someone drive who is not steady on the go pedal. Man I hate that.:duh: Oh... back to the OP. YES! get an auxillary ATF cooler if you will be doing regular towing. Any is better than none for regular heavy towing.

Joel

Yep, thats for sure. Thats because it isnt actually in full lockup mode at all, there is still some slip commanded by the PCM. :weird: Weird, but it works. When in D and rolling at like 70-75, a significant throttle change is required to force the trans out of lockup. The TC does slip a little more during this, but the PCM commands a little more lockup force and the little amount of slip reduces back to normal.

And, for the on/off lockup style, you dont have to tell me. It was getting really annoying when I had the Transgo in, sometimes it would force me back into the seat. Not exactly a good thing.

[hatchet669]

how many rings is the tranny cooler in the radiator? cause i was thinking about changing that to a oil cooler and just putting a new tranny cooler...

[ScarabEpic22]

how many rings is the tranny cooler in the radiator? cause i was thinking about changing that to a oil cooler and just putting a new tranny cooler...

I have no idea how many rings it is, I am pretty sure it is a different type than you are thinking of though...

What you really should do is install the aftermarket cooler after the factory one, so the ATF flows like this:

trans hot side->radiator/oe cooler->aftermarket cooler->trans cool side

[hatchet669]

k cool thanks man

[fooldancing]

Hey guys,

I was looking at My TB and I have a small radiator type deal in front of my radiator. MY TB has a tow package, and I was wondering if all of the TBs had this and if so, what might it be? I was under the impression it could be an aux. tranny cooler, but I can't say for certain. Also, do all of the TrailVoys come with a "tow package".

I haven't had a chance to go to a CAT scale yet, but I have been told my dry weight is around 4300lbs, and the max weight with it TOTALLY loaded (which I am not planning on loading this heavy) is 6000lbs. I know the latter is above the tow limit for the TB EXT. with 3.73 gears, but like I said I will not load it this heavy :nono: so it will be within specs.

Thank you everyone for the advice,
Matt M.

[muddy tires]

Hey guys,

I was looking at My TB and I have a small radiator type deal in front of my radiator. MY TB has a tow package, and I was wondering if all of the TBs had this and if so, what might it be? I was under the impression it could be an aux. tranny cooler, but I can't say for certain. Also, do all of the TrailVoys come with a "tow package".

Matt M.


Yes they all have the "tow package" - hitch reciever, and prewired. I think what you are seeing is the power steering cooler. The only tranny cooler from GM is integrated with the rad. They won't even recommend an aux cooler.

[fooldancing]

Great thanks, I wasn't sure what it was. How big of a cooler can I fit in the TB and where should/could I put it? I apologize if these are dumb questions, but I am an auto body tech not a mechanic. It doesn't sound like a hard job, I just want to get the right size and proper location.

Thanks again,
Matt