I recently bought a new travel trailer and a used truck to use as the tow vehicle. When I bought the truck I was told it had a 3.73 rear diff... anyhow after some investigation it has the 3.42. That drops the tow capacity down to 6700lbs from 7700lbs which is cutting it close for my rig ( Here are the details )
2008 GMC Sierra 1500 Crew Cab Shortbed
5.3L / 4L60e / 3.42 diff / 2WD / G80 locker
Trailer package
Heavy Duty rear suspension
Upgraded Transcooler to 24,000 GVWR (Hayden 678)
Jayco 267BHS
5690Lbs dry / 6200Lbs loaded
Equalizer WDH
The truck tows the trailer well in 3rd gear on the highway at 2400 - 2500rpm. Never downshifts unless it's a very steep hill. Acceleration is slow but acceptable. Transmission temps hover between 70C - 80C while towing during the summer.
I've done some smaller 2-3 hour trips already with the rig and it will cruise along quite happily on the highway. However I've got a longer 4000km trip later this year which has me thinking a bit.
Would going to a 4.10 from the 3.42 be worthwhile? It would move my cruise rpm up to 3000 in 3rd which seems unnecessarily high, but I assume would make accelerating a bit better.
It would cost me about $1000 to get the rear diff swapped, plus I would then need to get a programmer to correct the speed/transmission shift points.
The rig in question
2008 GMC Sierra 1500 Crew Cab Shortbed
5.3L / 4L60e / 3.42 diff / 2WD / G80 locker
Trailer package
Heavy Duty rear suspension
Upgraded Transcooler to 24,000 GVWR (Hayden 678)
Jayco 267BHS
5690Lbs dry / 6200Lbs loaded
Equalizer WDH
The truck tows the trailer well in 3rd gear on the highway at 2400 - 2500rpm. Never downshifts unless it's a very steep hill. Acceleration is slow but acceptable. Transmission temps hover between 70C - 80C while towing during the summer.
I've done some smaller 2-3 hour trips already with the rig and it will cruise along quite happily on the highway. However I've got a longer 4000km trip later this year which has me thinking a bit.
Would going to a 4.10 from the 3.42 be worthwhile? It would move my cruise rpm up to 3000 in 3rd which seems unnecessarily high, but I assume would make accelerating a bit better.
It would cost me about $1000 to get the rear diff swapped, plus I would then need to get a programmer to correct the speed/transmission shift points.
The rig in question
