4l80e+GV or NV4500+GV

[Thanos]

Anybody have one of these combos? If you do how does it do for towing etc?

Running 4:10s is why I am asking.

[special-K]

I haven't, but I can tell you all that overdrive on 4.10 ratio would suck for towing. 4.10 with overdrive is a sweet combo for a truck.

[67 chevelle]

Id do the 4l80 and skip the Gear Vendors ifthat is what you are asking , you dont need double overdive , 4l80 is a stout tranny

[burnin oil]

Both trans are stout. There is no way I would double OD a gas truck with 4.10 gears. The 25% OD will drop you from 3500 RPM to 2600 RPM. That is perfect for hauling a load. Double over would put you at just under 2k rpm. Unless that motor is a torque monster 500 Caddy you will be trying to run under the power curve on a decent hill. I would be willing to bet that the 2600 rpm would net a little better milage as the motor would be more efficient range and not adding extra drivetrain loss. Don't take that as gospel as I have never owned a GV but 2 of my trucks, both are diesels, have aux transmissions giving them double over. One has 4.44s with less final OD than the GV and only runs empty in that gear and the other had 671 cubes with 6.67 gears that redlines at 2100 RPM.

[JJorgensen52]

I've got an NV4500 in my K10, with 3.73s, and I can tell you it tows nicely but I usually have to downshift to 4th on any significant grade at highway speed (70ish), or else it starts to loose speed, the RPMs were just too low. I used to tow a 6800# trailer/tractor combo with it.

[Thanos]

Who tows in OD??? The Idea was to lower gears and have a "3rd over" 4l80e for towing or "4th over" standard. Double OD for non towing only. btw this will be with a 8.1 vortec.

I couldn't see the point of using GV without maxing the off the line gears @ 4:10 other wise double over wouldn't be useful at all.The 4l80e has a horrible first gear ratio btw fellas.

I guess I will have to find out first hand how good a set up over that will be.

[Chknlyps2]

The NV in 4th and the 4L in 3rd both have a 1:1 ratio, adding a gear vendors od which I think is 25% od would put you .75:1 ratio.

.75 ratio with 4.10 gears and a 33 inch tall tire your rpm at 60 MPH would be 1879

31 inch tall tire at 60 mph = 2000 rpm
30 inch tall tire at 60 mph = 2066 rpm
35 inch tall tire at 60 mph = 1771 rpm

And with the 4L80 you should probably add 100 rpm for slippage but they are pretty low on the rpm range for cruising at 55 or 60 mph

Hope this helps

[JJorgensen52]

Originally Posted by Thanos

Who tows in OD??? The Idea was to lower gears and have a "3rd over" 4l80e for towing or "4th over" standard. Double OD for non towing only. btw this will be with a 8.1 vortec.

I couldn't see the point of using GV without maxing the off the line gears @ 4:10 other wise double over wouldn't be useful at all.The 4l80e has a horrible first gear ratio btw fellas.

I guess I will have to find out first hand how good a set up over that will be.

I do?? No reason not to take advantage of the lower RPMs if the motor can handle it. I hate running 3k RPM on the freeway.

The NV4500 OD is 0.73 and the 1st (I have a late GM gearset) is 5.61 - I only use 1st for towing (2nd is 3.04, same as 1st in the 4L80E) and OD above 60mph most of the time.

That said, the NV4500 is NOT a smooth shifting trans. It drives very much like my SM465 used to - truck like. Off the line performance is pretty moot, at that point.

[The Chainsaw]

Skip the GV unless you have 4.56's or higher with a 30" or shorter tire.

Drove my dads 2007 suburban for the last week on a roadtrip.

6.0 engine
4L80e transmission
3.73 gears
245/75r16 tires

Got better mileage on flat ground going 70mph than 60mph. 60mph was 1900rpm and even the 6.0 was wanting to downshift on most hills. The 8.1 will be SLIGHTLY better at low rpm, but it still won't like cruising too much lower than 2000rpm even empty.

[Thanos]

Originally Posted by Chknlyps2

The NV in 4th and the 4L in 3rd both have a 1:1 ratio, adding a gear vendors od which I think is 25% od would put you .75:1 ratio.

.75 ratio with 4.10 gears and a 33 inch tall tire your rpm at 60 MPH would be 1879

31 inch tall tire at 60 mph = 2000 rpm
30 inch tall tire at 60 mph = 2066 rpm
35 inch tall tire at 60 mph = 1771 rpm

And with the 4L80 you should probably add 100 rpm for slippage but they are pretty low on the rpm range for cruising at 55 or 60 mph

Hope this helps

Fantastic! Love precise maths!

There is a 8.1 that does 450 lb·ft @ 2800 RPM, my tires will be 32 inches tall at max, I would tow @ 65+ and no less than 65 unless climbing extreme.I prefer most torque made at lower rpms on all my trucks, no reason to go over 3500 rpms for me anyway.

I have a ford (yuck I know) with the inline 300 it is at max torque at 2200 rpms, with 33 inch tires and 3:55 gears it does 76 mph in 5th @ 2200.Be interesting to turbo a overbuilt chevy 292...

Redid the calculations with 65 mph and 32 inch tires puts me at 2099... umph ok maybe I will look into 4:88's later =p

[Thanos]

Actually it was .78

[special-K]

Originally Posted by Thanos

Who tows in OD???

All the semi trucks on the hiway, and most anyone with a 4L80E or newer automatic and manual O/Ds. And, from your initial post, I was thinking you wanted to?

[MARKDTN]

Originally Posted by Thanos

Who tows in OD??? ...

Most anybody with a 4L60E or 4L80E. They have a tow/haul mode. I have put a bunch of towing miles on my '01 Tahoe DD. 5.3 and 4L60E. Right at 300K on the truck. Never had any trans work other than a fluid and filter change.

[burnin oil]

I always tow using OD and I own vehicles from a K20 up to a Mack road tractor. Sorry you don't like advice from people who know that it is a waste of time and money to do what you asked. Going by your response about crappy gears then get the GV under drive and keep the auto a single OD. More low end pull and get the motor where it needs to be. Honestly 450ftlbs is not all that much unless you drive a Honda 99% of the time. My 95 Dodge diesel made 440 ftlbs at 1600 rpm and a whopping 175HP. That thing was a turd stock. Look at the new diesels with warranties pushing 900ftlbs with a warranty! I am also the guy who uses granny gear in a transmission every single day and cannot think of having a truck without it. I run a pretty wild motor in the truck and do anything I want with it when I want. One of these days it will get a NV4500 but until then it gets the job done with the factory 4spd. Last month I hauled 75 tons of gravel with my 5500. The average load was 5 tons. I wouldn't even have tried it using double over but I sure enjoyed having 1000ftlbs of torque and the under drive gear in the auxillary transmission.

[burnin oil]

Originally Posted by MARKDTN

Most anybody with a 4L60E or 4L80E. They have a tow/haul mode. I have put a bunch of towing miles on my '01 Tahoe DD. 5.3 and 4L60E. Right at 300K on the truck. Never had any trans work other than a fluid and filter change.

Usually the tow/haul button adjusts the shift points, convertor lock up, and internal fluid pressures while keeping the OD function working.

[Thanos]

Tow/haul causes the trans to not shift into 4th and allows for the engine to rev higher before shifts, you NEVER tow in OD. I have 2500 HD with a allison they say DO NOT TOW IN OD. My suburban with a 4l80e would never shift into 4th when tow/haul mode is on.

I honestly thought everybody on here would know this however I am going to back out of this thread because its the wrong forum for this level of transmission knowledge. Thanks anyway.The Semi comment was a classic!

Call your local transmission shop about towing with OD on your 4l80e aka th400r4 ,nv4500,4l60e aka th700r4 ...

[JJorgensen52]

Originally Posted by Thanos

Tow/haul causes the trans to not shift into 4th and allows for the engine to rev higher before shifts, you NEVER tow in OD. I have 2500 HD with a allison they say DO NOT TOW IN OD. My suburban with a 4l80e would never shift into 4th when tow/haul mode is on.

I honestly thought everybody on here would know this however I am going to back out of this thread because its the wrong forum for this level of transmission knowledge. Thanks anyway.The Semi comment was a classic!

Call your local transmission shop about towing with OD on your 4l80e aka th400r4 ,nv4500,4l60e aka th700r4 ...

Just reading through the current 2500HD owners manual, and it specifically says:

"Vehicles can tow in D (Drive). Shift the transmission to a lower gear if the transmission shifts too often under heavy loads and/or hilly conditions."

Which is what pretty much everybody has suggested here. The big enemy of automatic transmissions is heat - as long as it isn't hunting and locking and unlocking the converter, there's no reason not to use it.

[The Chainsaw]

Originally Posted by Thanos

Tow/haul causes the trans to not shift into 4th and allows for the engine to rev higher before shifts, you NEVER tow in OD. I have 2500 HD with a allison they say DO NOT TOW IN OD. My suburban with a 4l80e would never shift into 4th when tow/haul mode is on.

I have towed using 10+ vehicles with 4L80e's, and not one of them prevents the shift into overdrive with tow/haul mode activated. Every one of them dropped temp vs staying in 3rd.

Also towed with several different d-max's with both the 5 and 6 speed alison, and again they all shift into overdrive even with the tow/haul mode activated.

Also towed with a couple 2015 dodge cummins with their new 6 speed, and they both go straight into OD with tow/haul mode activated.


The old 95 dodge cummins my brother has is the only one that doesn't shift into OD with tow/haul activated.

[Thanos]

I never tow in OD, I also don't compare diesel to gas engines it's completely different.One of the best transmission shops I have been to use to say "our best customers are the ones who tow in OD"

[The Chainsaw]

Originally Posted by Thanos

I never tow in OD, I also don't compare diesel to gas engines it's completely different.One of the best transmission shops I have been to use to say "our best customers are the ones who tow in OD"

What does the engine have to do with whether or not the transmission is able to do any towing in OD? That doesn't make any sense.

[The Chainsaw]

There is a huge amount of knowledge about transmissions on this forum, but it is wasted time with some people.

There are also people knowadays that still say the 327sbc was the best motor ever made. Get a hold of some other transmission builders that know what they are talking about if you don't like the advise here.

[Thanos]

Originally Posted by JJorgensen52

Just reading through the current 2500HD owners manual, and it specifically says:

"heavy loads and/or hilly conditions"

Everything in a 800 mile radius around me are hills and mountains galore, I will be towing up to 10K with a 72 with a BB in that terrain, I'm not risking OD thus my interest in a GV for 3rd over.

Hopefully that paints a better picture however I have found what I was searching for on another forum so thanks all.

[72MARIO]

Good luck with the gearvendors. I wish i would have just used a 4l80 in my suburban. They sure do a great job of marketing them. I hope you dont plan on backing that 10000 load up any hills or your GV will be cooked fast..

[JJorgensen52]

Originally Posted by Thanos

Everything in a 800 mile radius around me are hills and mountains galore, I will be towing up to 10K with a 72 with a BB in that terrain, I'm not risking OD thus my interest in a GV for 3rd over.

Hopefully that paints a better picture however I have found what I was searching for on another forum so thanks all.

Glad you found people who agree with you.

My only point was, your statement that the owner's manual prohibits towing in OD is false. It suggests shifting down from OD if the trans is hunting - causing overheat, converter and clutch wear.

One of the best things about this community is the wealth of knowledge and desire to share that exists here. Just want to be sure anybody who stumbles on this thread is getting the whole picture.

[Thanos]

Originally Posted by 72MARIO

I hope you dont plan on backing that 10000 load up any hills or your GV will be cooked fast..

Yes that was one of the complaints also one on vibration with a few models other than that most love em.They have worked many of the issues out and are getting better though.

Probably wait a while longer.