1998 sierra capacity question

[guys427]

Hi,
Newby here. We have been RVing for 6yrs now, both with travel trailers and mh.
Now going back to travel trailer( not aquired yet)
But I do have some questions regarding the Trailer Life towing guide for our (low millage) 1998 Sierra pickup.Auto w/o.d
It says in every cetegory of engines require 4.10 gears,along with the engine oil cooler etc... so, why is all weight ratings have all the requirements

Our last tow vehicule was a 1993 G2o ext van with 3.42 rear
we hat to tow in 3rd all the time
Our sierra has the same rear end, but we could change to 3.73 if needed. We'll be adding the trans cooler and ( if absolutly required) an engine oil cooler
We are looking at a 2000-2700lbs trailer
Any thoughts will be helpfull.

Guy and Annie

[guys427]

Thank you,
I was expecting that the engine oil cooler was a bit much for the weight.
Incidently, as a follow up to my post, the z82 hitch is square tubing, I'm thinking '99 and up were round.
In 2013 I did frequent oil change(and filter) + a bottle of Lucas( was so much cheaper in the US)mainly because I was keeping the engine rpm between 2750-3000 all day((avrage 7-8hrs)every day we were on the road and thought it was over working the motor a bit, it sure wasnt your typical Sunday drive.
If we do this again, I'd probably do the same thing.
The remote filter for the trans was an idea i had after showering with warm trams fluid last year on my MH. It cost little( filters are about $20) and eliminate's the need to drop the pan a couple times a year.
Thank you to all that chimed in.
Guy

[Turtle_n_Peeps]

guys427 wrote:
Thank you to all, this is a lot of great info.
So in the end the tow vehicule is equiped with the Z82 towing option(thereis a cooler of some kind there) with a GT4 rear end(3.73:1 ?)Factory hitch.
The reason for wanting to be on the safe side of things, even towing a relatively small TT, is that we usaully go lond distances(2013 netted a 41 day 11500km raod trip that lead us from Montreal to
San Diago via Nashvill and the Louisanna gulf coast.
Some hairry monents through the rockies(I10) and I40 on the way back.
Just want 2 be safe this time to Northern California.
I do plan on: trans temp gauge- remote trans filter( spinn on ) synthetic oil.Frequent engine oil changes(2000-3000mi.)
Just wondering if the engine oil cooler is overkill?
More info please

Tranny gauge is fine, trans remote filter is way, way over kill. Synthetic oil is fine but dino is also fine. Oil changes is off the chart over kill. Engine oil cooler is over kill too.

Sometimes doing things that you think is good can cause unintended consequences. The engine oil cooler for instance. An oil cooler in front of the cooling stack adds to the thermal load which "can" cause heating problems for the engine.

Make sure you have a good tranny cooler. Make sure the cooling stack is clean. Make sure all the fluids are fresh and call it a day and go on vacation.

Have fun!

[BenK]

guys427 wrote:
snip....

Just wondering if the engine oil cooler is overkill?
More info please

You should already have one. It comes with the Tow Option

Look at your main radiator. It is a cross flow design with the hot tank
on the drivers side and the cold tank on the passenger side

Notice on the pic of mine and the aux ATF cooler lines. They run down
and to the passenger side...then up to the main radiator cold tank

The engine oil lines will poke into the main radiator on the hot tank
on the drivers side. No external engine oil cooler...just into the
main radiator

If you wish to install an external engine oil cooler, make sure it is
of the tube/fin design. Plate type won't/can't take the PSI

[guys427]

Thank you to all, this is a lot of great info.
So in the end the tow vehicule is equiped with the Z82 towing option(thereis a cooler of some kind there) with a GT4 rear end(3.73:1 ?)Factory hitch.
The reason for wanting to be on the safe side of things, even towing a relatively small TT, is that we usaully go lond distances(2013 netted a 41 day 11500km raod trip that lead us from Montreal to
San Diago via Nashvill and the Louisanna gulf coast.
Some hairry monents through the rockies(I10) and I40 on the way back.
Just want 2 be safe this time to Northern California.
I do plan on: trans temp gauge- remote trans filter( spinn on ) synthetic oil.Frequent engine oil changes(2000-3000mi.)
Just wondering if the engine oil cooler is overkill?
More info please

[BenK]

Ops...brain fart...apologize for that

Bryan, you are right...it is with the round GMT800 platform receiver failing
on 'some' TVs...NOT GMT400, like the OP's square cross tube





A traditional designed receiver cross tube uses the cross tube as a
torque tube...the GMT800 receiver loads the round cross tube mainly
as a beam loading...with some or small amount of torque loading

[Thunderbolt]

If I remember correctly the hitch on a GMT400 was made by Valley and is square tubing. My hitch has been great on my 98 Chevy. It is the 99 and up Silverado with the round tubing that has issues. Correct me if I am wrong because I am not sure. Either way pulling 2,700 lb trailer should be a breeze. I have the 6,600 GVWR truck with 3.73's with tow pacckage and had no issues with 6,000 lbs. That was years ago though. That is my daughter's truck now and has 375,000 miles on it. Things keep wearing out now though. LOL

BenK wrote:
Most OEM brochure and published specifications are derived from a curb
TV...meaning a stripper model...even though a stripper might not be
offered for sale

So best to weigh your TV fully loaded as if going to tow. Then do the
simple math subtracting the actual weight from the GCWR.

GCWR can be figured close (ball park) by taking the curb and adding
the brochure MTWR (Max Tow Weight Rating)

Then the generic formula is: GCWR >= actual TV + actual trailer + stuff
like WD hitch, cargo, people, pets, ice chest, luggage, etc, etc













This is for a 2001/2002 era (GMT800...yours is GMT400), but it shows
how diff ratio's affect MTWR




If the TV's receiver is still OEM, suggest replacing with a traditional
designed receiver. The better ones range from $150.00 on sale to
a bit over $200. Plus about an hour to remove the POS old and install
the new, traditional design receiver

A POS and below is/was a common issue that was supposedly fixed, but
have found other complaining about it on their 1999...

Not just poor welding, but the basic design is awful and why say replace
with a traditional designed receiver

[BenK]

Forgot:

If yours does NOT have the factory tow option, then install the engine oil cooler
(it runs to the hot tank of the main radiator), an external ATF cooler and do NOT
tow heavy in OD

Get the largest AFT cooler you can stuff in there and plate types best for this
application.

This is a picture of my Suburban while in the shop fixing the damage hitting a
SUV which jumped a stop sign...

It is on the drivers side of the center support/horn...right side
on this image and between that and the headlamp is the power steering
fluid cooler (tube/fin type)

[BenK]

Most OEM brochure and published specifications are derived from a curb
TV...meaning a stripper model...even though a stripper might not be
offered for sale

So best to weigh your TV fully loaded as if going to tow. Then do the
simple math subtracting the actual weight from the GCWR.

GCWR can be figured close (ball park) by taking the curb and adding
the brochure MTWR (Max Tow Weight Rating)

Then the generic formula is: GCWR >= actual TV + actual trailer + stuff
like WD hitch, cargo, people, pets, ice chest, luggage, etc, etc













This is for a 2001/2002 era (GMT800...yours is GMT400), but it shows
how diff ratio's affect MTWR




If the TV's receiver is still OEM, suggest replacing with a traditional
designed receiver. The better ones range from $150.00 on sale to
a bit over $200. Plus about an hour to remove the POS old and install
the new, traditional design receiver

A POS and below is/was a common issue that was supposedly fixed, but
have found other complaining about it on their 1999...

Not just poor welding, but the basic design is awful and why say replace
with a traditional designed receiver

[Chuck_thehammer]

Never believe Dry Weight of trailers... that is without battery, propane tanks, other factory options..

my trailer is 800 pounds more than posted on trailer tags. so 10 percent more.

[SoCalDesertRid1]

Actually, for GM trucks of that era, the max tow rating was with 4.56 gears.

In any case, the 2700 lb trailer will tow just fine with 3.42 gears.

[bikendan]

hope you aren't using fictional brochure/website "dry" numbers.
those are never realistic.

[Grit_dog]

You post zero details about your truck, but even if it has the 4.3v6 it will tow 2700lbs safely. You're good to go.

[boogie_4wheel]

I had a '97 GMC K1500 (350/4L60E/3.73) that had a 6600lb GVWR. The GCWR was 12k and the max trailer weight was 6500lbs. I do not remember what the 4.10 axle gained you for weight, and what the 3.42 made you lose.

For a trailer at 3k, you will be just fine. Depending on grade and wind resistance, you will most likely need to still lock out 4th. With the 3.42 gears, you will still be under the peak torque output in 3rd at speed.

If you desire to monitor the transmission temperature, a probe can easily be added to the pressure test port located on the driver's side of the transmission, just above where the shift linkage ties to the case.

mkirsch wrote:
Trucks of that era did not come with transmission coolers at all.

The transmission cooler is due to the fact that there is no torque converter lockup, so the power is transmitted through the transmission fluid, which makes it hot.

They did come with transmission coolers. They were oil/water units built in to the radiator. Some were optioned with a second aux oil/air cooler that was located on the passenger side of the grille area. Mine (without the tow package) included the aux transmission cooler.

Also, these did have a locking torque convertor. They locked in 3rd and 4th (OD), but they did not have a Tow/Haul mode to change the shift and lockup strategy.

[mkirsch]

For the MAXIMUM weight ratings, a 4.10 axle ratio is required.

If all you're towing is 2700lbs, then a 3.42 will be fine. You do want to make sure to have a large heavy-duty transmission cooler, though. Trucks of that era did not come with transmission coolers at all.

The transmission cooler is due to the fact that there is no torque converter lockup, so the power is transmitted through the transmission fluid, which makes it hot.