ryanlsmith
Well-Known Member
- Thread starter
- #1
After much back and forth (and eventually back again), I finally was able to get a set of Yukon 5.13 gears installed. Between apparently shady Amazon sellers sending me damaged gears (tried both Dana Spicers and Yukons), and unexpected lead times from other shops, @Northridge4x4 came to the rescue and had Yukons in stock, and they arrived in pristine condition.
Also lucked out with a reputable local shop getting me in fairly quickly, and did the job in a day and a half (also installed Eaton locker up front).
It’s worth noting that I’m writing this with just 90 miles on them, having gone through roughly 5 heat cycles of 15-20 miles. For that reason, I’ve not done any excessively aggressive acceleration, with the exception of some moderately heavy acceleration under load on the freeway for safety reasons, which was also restricted until ~50 miles and 3 heat cycles.
What I really wanted to highlight is how it immediately solved my speed/RPM/gearing issue due to the 37” KO2s. Prior to the regear, my stock 3.73 ratio would not let the computer be happy going into 8th or even 7th at freeway speeds. Even at 70-80mph, it would want to stay in 6th. In fact, if I had the adaptive cruise control set to 70-72 mph and manually shifted into 8th - the speed would start dropping from the RPMs being so low (I think it was in the 1400-1500 range).
Now it runs through the entire gear set without hesitation and uses 8th without complaining. At 70mph in 8th I see roughly 2100 RPM. It appears I may get a couple extra MPG as a result, but time will tell. If nothing else, I’m happy it can leverage what the transmission has to offer and allow the computer to work more effectively. After another 10-20 miles, I’ll feel more comfortable pushing it a little harder to see what acceleration improvements have been had.
Also lucked out with a reputable local shop getting me in fairly quickly, and did the job in a day and a half (also installed Eaton locker up front).
It’s worth noting that I’m writing this with just 90 miles on them, having gone through roughly 5 heat cycles of 15-20 miles. For that reason, I’ve not done any excessively aggressive acceleration, with the exception of some moderately heavy acceleration under load on the freeway for safety reasons, which was also restricted until ~50 miles and 3 heat cycles.
What I really wanted to highlight is how it immediately solved my speed/RPM/gearing issue due to the 37” KO2s. Prior to the regear, my stock 3.73 ratio would not let the computer be happy going into 8th or even 7th at freeway speeds. Even at 70-80mph, it would want to stay in 6th. In fact, if I had the adaptive cruise control set to 70-72 mph and manually shifted into 8th - the speed would start dropping from the RPMs being so low (I think it was in the 1400-1500 range).
Now it runs through the entire gear set without hesitation and uses 8th without complaining. At 70mph in 8th I see roughly 2100 RPM. It appears I may get a couple extra MPG as a result, but time will tell. If nothing else, I’m happy it can leverage what the transmission has to offer and allow the computer to work more effectively. After another 10-20 miles, I’ll feel more comfortable pushing it a little harder to see what acceleration improvements have been had.
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