4 Spd. Versus 6 Spd. Transmission

[GPGuy]

Just wondering if anyone has had the 4 spd. transmission and moved up to the 6 spd. now offered? Is there a big difference? Performance? Mileage? Towing? etc.

[fraiolib]

my stepdad has a 08 5.3 3.42 4spd and i have a 10 5.3 3.08 6spd i do get slightly better millage than him not a big difference maybe .5 but im 18 i probly drive a little harder than he does. i dont notice anything performance wise. towing the 6spd is AMAZING!!! with 5th and 6th being overdrive gears its really nice on the highway. my truck does 90mph at 2k in 6th. it shifts extremely smooth you dont even feel a shift. theres some ppl on here complaining about the 6spds saying they shift too much but i think its way better than the 4spd

[ColoradoSkiCountry]

Not sure if this counts, but Had an 07 Sierra 1500 5.3L 4-Speed and then went to my 08 2500 Duramax 6-Speed Allison- one HELL of a difference!!!

[Big Whiskey]

I went from an '07 VMax 4spd with 3:73's to an '09 VMax 6spd with 3:42's. Both were/are stock. I'm getting 2-3 mpg better with the '09. At first I didn't like the extra shifting, but now I don't even notice it. When it shifts, the RPM's don't drop a lot like the 4spds do, the 6spd is really smooth. I like the acceleration better too. With that really low 1st gear on the 6spd, it takes off like a jack rabbit and the engine stays in it's power band while shifting through the other gears. I think towing is better as well. On the 4spd with 3:73's, towing in 4th was sometimes too high, but 3rd was too low. That new 5th gear is perfect.

 

Even though I thought they were just fine in the past, I will never go back to a 4spd now that I've gotten used to my 6spd. More power and better MPG!

[jblakeney]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

[07BlueSierra]

Went from a 07 Sierra 5.3 with 3.73 to a 10 Tahoe 5.3 3.42. I am probably getting 4-5mpg better. That probably has something to do with the 285 BFGs though. then new one does have the heavy 20s though.

[Matt_]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

 

its actually a much larger difference then tha. you fail to take into account the low 1-2-3 setup in the 6spd. so you can run 3.42s with a 6spd and have a low end gearing advantage over a truck with 4.10s and the 4spd... so that 3.42 setup will get you off the line faster and pull harder.

 

then jump to highway cruising... whats going to run at lower rpms: 3.42s with a .67 6th gear or 4.10s with a .70 4th gear? the answer is simple.

 

we've discussed the 6spd vs 4spd quite extensevly on this forum. the benefits are clearly there. i had the 4spd prior to my 6spd and will never go back. there were too many times where the 4spd cant get in the right gear because its either too much or too little rpm..... no issues with that at all in the 6spd truck.

[Big Whiskey]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

 

its actually a much larger difference then tha. you fail to take into account the low 1-2-3 setup in the 6spd. so you can run 3.42s with a 6spd and have a low end gearing advantage over a truck with 4.10s and the 4spd... so that 3.42 setup will get you off the line faster and pull harder.

 

then jump to highway cruising... whats going to run at lower rpms: 3.42s with a .67 6th gear or 4.10s with a .70 4th gear? the answer is simple.

 

we've discussed the 6spd vs 4spd quite extensevly on this forum. the benefits are clearly there. i had the 4spd prior to my 6spd and will never go back. there were too many times where the 4spd cant get in the right gear because its either too much or too little rpm..... no issues with that at all in the 6spd truck.

 

 

 

^^^ I agree 100%. It's much more beneficial than just "2 extra gears."

[music]

I've posted some threads on this topic in the past. I test drove some 5.3/6-spd/3.42 trucks earlier this year, purely to evaluate towing performance. I couldn't hook up to the camper, but I did run various hills/scenarios to see how the rpms/shifts felt. For towing, it would be an improvement for most conditions, but not all (the new 3rd gear may not be steep enough for some grades with my camper compared to 2nd on my truck). For daily, normal driving (not towing or racing)... the two feel about the same (I mean, who pays attentions to low throttle shifts, except for enthusiasts?). My 4-spd drops ~300 rpms between "normal throttle" shifts. Under load or high acceleration, the 6-spd is the clear winner... but not in an earth shattering kind of way. If you own a solid 4-spd truck, there's not much reason to change *just* for the 6-spd. If you're buying a new truck anyways, get the 6-spd. Economy is virtually identical (~4% max according to GM).

 

If I were to personally buy a new truck tomorrow, I would take a 5.3/6-spd/3.42 over a 6.x/4-spd (for towing... all else equal). It offers the better combo of power/gearing/economy for towing and daily driving. A NHT truck (6.2/6-spd/3.73 with +300 lbs of payload) would be the best 1500 option for towing "heavy", but now you have to compare to the 2500HD. Always something a little better to consider...

[jblakeney]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

 

its actually a much larger difference then tha. you fail to take into account the low 1-2-3 setup in the 6spd. so you can run 3.42s with a 6spd and have a low end gearing advantage over a truck with 4.10s and the 4spd... so that 3.42 setup will get you off the line faster and pull harder.

 

then jump to highway cruising... whats going to run at lower rpms: 3.42s with a .67 6th gear or 4.10s with a .70 4th gear? the answer is simple.

 

we've discussed the 6spd vs 4spd quite extensevly on this forum. the benefits are clearly there. i had the 4spd prior to my 6spd and will never go back. there were too many times where the 4spd cant get in the right gear because its either too much or too little rpm..... no issues with that at all in the 6spd truck.

 

 

Come on apples to apples comparisons.... You have to compare 3.42's with BOTH transmissions... Using a 4.10 ratio on the 4spd...... That makes it really difficult to see a comparison.

 

The six speed the gears are MUCH closer together than the 4 speed simply because there is MORE gears. So the transmission should be snappier just because it is shifting through the gears and keeping the RPM's down lower.

 

3.42 to 4.10 comparison is an unfair comparison.

 

Jbo

[rockcrusherrevived]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

 

i have a gearvendors on my 82 .73 overdrive on any gear

[Matt_]

Not much other than 2 gears extra to split the shifts up some more. Final ratio out of the transmission is near the same 4l60e is .7 and 6l60e is .67......

 

I have toy-d with the idea of putting a gear vendors double over drive unit in my truck...... I drive quite a bit on the interstate.... It would pull the rpms down..... Double over drive in 4th final drive is .55.

 

Its only .03 difference in the two when in the top most gear in over drive.

 

Jbo

 

its actually a much larger difference then tha. you fail to take into account the low 1-2-3 setup in the 6spd. so you can run 3.42s with a 6spd and have a low end gearing advantage over a truck with 4.10s and the 4spd... so that 3.42 setup will get you off the line faster and pull harder.

 

then jump to highway cruising... whats going to run at lower rpms: 3.42s with a .67 6th gear or 4.10s with a .70 4th gear? the answer is simple.

 

we've discussed the 6spd vs 4spd quite extensevly on this forum. the benefits are clearly there. i had the 4spd prior to my 6spd and will never go back. there were too many times where the 4spd cant get in the right gear because its either too much or too little rpm..... no issues with that at all in the 6spd truck.

 

 

Come on apples to apples comparisons.... You have to compare 3.42's with BOTH transmissions... Using a 4.10 ratio on the 4spd...... That makes it really difficult to see a comparison.

 

The six speed the gears are MUCH closer together than the 4 speed simply because there is MORE gears. So the transmission should be snappier just because it is shifting through the gears and keeping the RPM's down lower.

 

3.42 to 4.10 comparison is an unfair comparison.

 

Jbo

 

 

 

do you even know that the gearing in the transmissions are? this isnt the failed chrysler 6spd where they kept the same gear range and just shortened the shift point... low end gears in the 6L80E are much lower than the 4L60E.

 

ok lets compare "apples to apples"... a 6spd 3.42 truck will run circles around a 4spd 3.42 truck

 

thus i am comparing apples to apples, the advantage to the 6spd truck is the ability to run 3.42s and have a much stronger final drive ratio than a 4spd truck with even 4.10 gears. you would need 4.56s in a 4spd truck to match the final drive ratio of 1st gear. and then, when cruising on the highway you have 3.42s instead of 4.10s or 4.56s in OD.

 

any other OEM option going to accomplish that? theres an orange for you.

[sc4808]

Good question, I have not driven one of the 6 sp trucks but I would have to think that the extra gears would help when towing, the closer ratio's would have to help with getting the load moving.

[music]

Good question, I have not driven one of the 6 sp trucks but I would have to think that the extra gears would help when towing, the closer ratio's would have to help with getting the load moving.

 

I forgot to mention that. The difference will be accelerating (most noticeable would be merging uphill onto an interstate), and rolling through hilly or mountainous terrain. When towing in moderate terrain, I would stay in one gear pretty much all the time (3rd on the 4-spd, 4th on the 6-spd)... so little difference once the load is "up to speed". Auto-grade braking is the other nice feature on the 6-spd--very handy when towing.

[RyanbabZ71]

I wish my 08 Tahoe was a 6 speed.

 

Also my fav feature on the 6 speed is the engine braking with tow haul.