1998 sierra capacity question

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

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.

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.

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.