4.2 Towing. ATF Cooler. "Heavy Duty Trailering Equipment"

[GreenBravada]

I have a 2003 Bravada with the 4.2 and planning to tow an 1800 pound pop-up camper. There are just springs in the rear suspension. No auto-leveling airbags. No compressor.

1. The original window sticker specs it as having a standard "Heavy Duty Trailering Package"
Does anyone know what was included in this? I do have a hitch and the necessary wiring harness.
I don't see a trans oil cooler. Can't see any markings on the alternator to tell what it is.

2. Is there any way to tell whether you have the 130 or 150 amp alternator? Apparently they require different serpentine belts.

3. I've watched several videos about installing a trans cooler. All have been done on a Trailblazer or possibly Envoy. When I look at the radiator in my Bravada with its "stylish" front end, the structure seems different and there doesn't appear to be room for a trans cooler. I was planning on using a Derale 13503 Series 8000 Plate and Fin Transmission Oil Cooler, but there seem to be structural supports for the grille that did not appear to be there on the Trailblazer.

Thanks for any advice or help!

​

 

[TequilaWarrior]

I have a 2003 Bravada with the 4.2 and planning to tow an 1800 pound pop-up camper. There are just springs in the rear suspension. No auto-leveling airbags. No compressor.

1. The original window sticker specs it as having a standard "Heavy Duty Trailering Package"
Does anyone know what was included in this? I do have a hitch and the necessary wiring harness.
I don't see a trans oil cooler. Can't see any markings on the alternator to tell what it is.

2. Is there any way to tell whether you have the 130 or 150 amp alternator? Apparently they require different serpentine belts.

3. I've watched several videos about installing a trans cooler. All have been done on a Trailblazer or possibly Envoy. When I look at the radiator in my Bravada with its "stylish" front end, the structure seems different and there doesn't appear to be room for a trans cooler. I was planning on using a Derale 13503 Series 8000 Plate and Fin Transmission Oil Cooler, but there seem to be structural supports for the grille that did not appear to be there on the Trailblazer.

Thanks for any advice or help!

​

I'm 99% sure the Heavy Duty Trailering Package for these is just that... a hitch and wiring harness. I don't know that these ever came from the factory with a transmission cooler.

Your Alternator would be indicated probably by an RPO code - on the glovebox door. U60 seems to spring to mind and a quick google search suggests that it's correct for the 150 AMP alternator.

The radiator support should be more or less identical amongst the several models. Whether our fiberglass front clip makes installation of a trans cooler any more difficult is hard to say. Every trans cooler I've installed gave various options for mounting, up to and including plastic posts that went through the actual radiator itself. If you're hell-bent on installing a trans-cooler, be prepared to fab up some brackets and you should be good to go. But honestly, you'd do yourself a whole bunch better just changing out ALL of the transmission fluid for DEX VI in lieu of installing a cooler. 1800 lbs isn't all that heavy and your rig should do just fine.

 

[GreenBravada]

There does seem to be some structural plastic in places where the Trailblazer has none.

I suppose the Dex III vs. Dex VI is a discussion that has been made many times on this forum. (I'm new...) Obviously, the owner's manual specifies Dex III but I have heard that GM would specify Dex VI these days. I have read that you shouldn't put Dex II into a trans specd for Dexron VI.

 

[Mooseman]

Whether you tow or not, it's a good idea to add an aux cooler. Check this thread for install:

Transmission Coolers..

Ok, so here I am trying to search through the forums on this subject. And I keep getting lost in threads, I swear I could read these for hours, lol! Anyways, does anyone have a suggestion on an aux transmission cooler (to go along with the stock one from the factory tow package, I think) that...

gmtnation.com

I'm pretty sure that behind the grill, all GMT360 are relatively the same.

As for the alternator, you have the 150A. Years ago, they used to list a 130A belt option for some odd reason. The only difference is the LWB trucks (EXT/XL) had a shorter belt because of the smaller power steering pulley. All others use the same belt. All have the same 150A alternator. Most parts listings have fixed this but there are a couple still out there with the wrong info.

Edit: Just looked at the belt listings for the Bravada on RA and they never fixed it. Check out listings for the TB instead.

 

[GreenBravada]

Found the RPO list here and confirmed 150 amp alternator. Thanks for the added info.

Take a look at the diagram below. This is pretty much what I found on my Bravada. A lot of stuff that's not on the Trailblazer. Getting the trans cooler in there will be a little trickier.

 

[GreenBravada]

This is from the AC Delco online catalog. Bit confusing for us newbies.

 

[Mooseman]

I've never really looked under the hood of a Bravada. Hell, even the true oddball Saab 9-7x was fine for an aux cooler.

As for the belt, the confusion was probably started by GM, hence the ACDelco screwed up. However, when I checked the ACDelco site (which takes me to GMParts.com), for the Bravada, it gives neither of those numbers. I got 12593774 and doesn't mention the alternator amperage at all.

Site Maintenance

Found the online catalog you were referencing and the original part number that you didn't screenshot is there. Only the two Professional belts they didn't fix.

 

[TequilaWarrior]

Having been between the grill and radiator on my Bravada dozens of times, there's room... but the shape of things inside there may make it "interesting" ... hence my statement about being ready to fab up some brackets... there's tons of room but making it look good may take some creativity.

It's not recommended to mix grades of Dex... Dex III is not really maintained as a licensed product anymore. MANY manufacturers still make a fluid they claim meets Dex III... Dex VI is the currently licensed standard from GM... it's fantastic stuff, a bit expensive, but it's worth the upgrade.

If you have more than 100k miles on the Transmission fluid, change the entirety of the fluid and the filter.
If you have more than 50k miles on the transfer case (assuming you have an AWD Bravada) change the tcase fluid TWICE with only genuine GM Auto-Trak II (driving a few hundred miles between changes).

 

[GreenBravada]

As I said, I'd bet there is a lot of back and forth here about using Dex 3 or Dex 4. The companies that market these two types very definitely say NOT to use Dex 4 in this transmission. Now, I know that genuine Dex 3 is supposedly obsolete, but I've also read that Dex 4 is a much thinner viscosity. I use "Dex III" in my Volvos because that is what is specified for the Japanese transmissions in them.

Tequila, would you by any chance be able to document that GM recommends using Dex 4 in our transmission? Not that I don't believe you or doubt your experience OR your reasoning, but you know how there's always conflicting info on the internet. Was there a service bulletin or something?

 

[GreenBravada]

As I said, I'd bet there is a lot of back and forth here about using Dex 3 or Dex 4. The companies that market these two types very definitely say NOT to use Dex 4 in this transmission. Now, I know that genuine Dex 3 is supposedly obsolete, but I've also read that Dex 4 is a much thinner viscosity. I use "Dex III" in my Volvos because that is what is specified for the Japanese transmissions in them.

Tequila, would you by any chance be able to document that GM recommends using Dex 4 in our transmission? Not that I don't believe you or doubt your experience OR your reasoning, but you know how there's always conflicting info on the internet. Was there a service bulletin or something?

I also know from working with the Rover V8 that the service manual torque numbers and procedure and specified gasket will certainly fail. Experience has dictated a different procedure, but all the official doc are out of date, and lots of people do it wrong causing big problems. Things change.

 

[GreenBravada]

I'm going to flush the fluid by catching the outlet of the pump and adding new fluid to clear the torque converter.

Reading on the web, I'm pretty convinced to use Dex 6, but I did run across this in a pretty authoritative article:

"The lower viscosity in the Dexron 6 can cause reduced protection on old transmissions designed to use Dexron 3. You may also notice a reduced performance when the vehicle shifts and experiences slippage."

My trans has 118 k miles on it. This is the first one of these I have driven. It seems to me that it is pretty lazy and not that positive shifting especially from first to second. I am going to be towing, so the last thing I want is slippage.

Thoughts?

 

[GreenBravada]

I'm reading that the 1-2 shift is commonly "gradual" at part throttle in the boxes, so I think my trans is working normally. Also, I am guessing that the computer "learns" my driving style over a period of time.

 

[Mooseman]

DexVI is the new standard fluid for Dexron. I used it in my 2002 and it lasted way longer than it should have. My 07 with basically the same tranny specs DexVI so feel confident that you'll be fine with it. It is way better than the old DexIII since it is synthetic whereas the DexIII is not.

 

[GreenBravada]

I'm sold. ;-)

 

[TequilaWarrior]

I'm going to flush the fluid by catching the outlet of the pump and adding new fluid to clear the torque converter.

Reading on the web, I'm pretty convinced to use Dex 6, but I did run across this in a pretty authoritative article:

"The lower viscosity in the Dexron 6 can cause reduced protection on old transmissions designed to use Dexron 3. You may also notice a reduced performance when the vehicle shifts and experiences slippage."

My trans has 118 k miles on it. This is the first one of these I have driven. It seems to me that it is pretty lazy and not that positive shifting especially from first to second. I am going to be towing, so the last thing I want is slippage.

Thoughts?

Changing to Dex VI was probably the second biggest change in drivability that I experienced with my Bravada. The first being changing my transfer case fluid as it was locked up... the two fluid changes freed it up and made it a pleasure to drive. Remember that you're driving an Oldsmobile... it's "luxurious". A "soft" 1-2 shift is pretty normal. If it revs between 1 and 2 that's perhaps a point of concern, but a soft 1-2 shift is so you don't experience a harsh shift. If you were to install a shift kit and program your PCM you can make that 1-2 shift feel like you've been rear ended.... the exact opposite of the spectrum. I wouldn't sweat a comfortable 1-2 shift....

FYI... I'm pushing 350k on my Bravada.... with a completely original drivetrain with basically fluid/filter changes and not much else.

 

[GreenBravada]

TequilaWarrior, I've received quite a lot of info and good advice from several people in this forum, but I think you're the only "Bravada Bro" I've met! ;-)

I guess the guys with the more "stylish" GMT360s need to stick together! My Bravada is in excellent shape with one exception: I will need to work on the rear upper control arm pockets before too long. For a car that spent its entire life in Michigan and Ohio, it's remarkably rust-free except for those two structures "designed" to rot. It's nowhere hear as bad as some photos I've seen online.

 

[TequilaWarrior]

I'm in the same boat. My wife got me a nice little welder for Christmas just so I can try to do the UCA pockets myself. Truthfully - I'll give it a shot, but know full well I may end up having to have someone do it for me for safety reasons as I haven't done any significant welding in almost 25 years. I had to replace my upper trailing arms because one of them was actually snapped.... and I discovered it not long after passing my yearly inspection.

I love my Bravada. My wife is after me to get rid of it but I just can't bring myself to do so. It's served me exceptionally well over the years.

 

[flyboy2610]

There are three tips to successful welding: practice, practice, and practice! And get yourself a good auto-darkening helmet. I have a Lincoln helmet and it works super! I also have an AutoArc helmet by Hobart. It works OK, but I usually leave that one in 'grind' mode, and use the Lincoln helmet for welding.
Also get a flint striker, such as those used by gas welders.

Tool Shop® Flint Striker

This flint striker features a spring steel with three flints and is zinc-plated.

www.menards.com

I use this to check the sensitivity of my weld helmet. If I hold the striker in front of my helmet, strike an arc, and my helmet doesn't immediately darken I know it's not set right or it needs a new battery.
You should probably be able to get a good helmet for around $150. Just don't buy a $19 no-name helmet from the clearance rack at Billy-Bob's Bargain Barn!

 

[GreenBravada]

There are three tips to successful welding: practice, practice, and practice! And get yourself a good auto-darkening helmet. I have a Lincoln helmet and it works super! I also have an AutoArc helmet by Hobart. It works OK, but I usually leave that one in 'grind' mode, and use the Lincoln helmet for welding.
Also get a flint striker, such as those used by gas welders.

Tool Shop® Flint Striker

This flint striker features a spring steel with three flints and is zinc-plated.

www.menards.com

I use this to check the sensitivity of my weld helmet. If I hold the striker in front of my helmet, strike an arc, and my helmet doesn't immediately darken I know it's not set right or it needs a new battery.
You should probably be able to get a good helmet for around $150. Just don't buy a $19 no-name helmet from the clearance rack at Billy-Bob's Bargain Barn!

Thanks, Flyboy. I think I have all of the necessary equipment. Just need the practice, practice, practice. I can make some pretty nice welds on thicker metals, but have the usual issues with sheet metal. I think I might do pretty well on the metal involved here. Not a line of nickles, but...