Gear Vendor Overdrive

[vernj4]

Have 4.10 gears ('95 C3500 w/ automatic) for towing........seems like a GV ovedrive would give one the best of both worlds....tow capacity AND good fuel economy. Any thoughts?

[britannic]

They're great units, but expensive, unless you can find a secondhand one. Which transmission do you currrently have?

[vernj4]

Got the -80..........seems to work well. Will be looking into installing the switch to activate the the torque convertor lockup...seems like it would be good when coming down a steep hill.

[britannic]

If "-80" means the 4L-80E, then you have a very strong tranny with a .75 OD ratio. The Gear Vendors may be overkill, since you already have an OD. I have the 700R4 with 4.56 diffs and find the rpms with 33" tires aren't bad at all at freeway speeds.

[Heartbeat Hauler]

I don't think the GV is overkill on the 4L80E for this reason. When I had my '94 CC dually, I was told not to tow in overdrive. This means that you are going to be towing in 3rd(1:1), with 4.10s the motor is turning some rpms(3061 w/31.5in. tires @ 70mph). With the GV, you are actually driving in 3rd overdrive which equates to 3.12(2330 w/31.5in tires @ 70mph). This is almost what the tranny overdrive is and you don't have the wear&tear on that clutch pack, not to mention less trans heat. Then when you are running solo you will have 4th overdrive (dbl OD) with a final drive of 2.40. I agree, they are expensive at $2200 + 4-500 bucks install.
JP
JP

[Johnny B.]

Vernj4, I know what you mean about towing with the same setup. I use OD otherwise I would be pretty much limited to 55mph on interstates in 3rd. I have heard many state that you have a higher trans temp by towing in OD and heat is the killer of a transmission. I don't notice much of a difference in temps while towing my travel trailer in OD or 3rd. If anything I would say under most conditions where OD can be used my trans runs cooler in OD.

A GV would be nice, but in a $5000 truck and driving about 10,000 miles per year I just couldn't justify one. You would have to burn quite a bit of fuel to make the GV worth your while.

[moondoggie]

Good Day!

You may want to look at What's your fuel mileage with a load? (http://forum.thedieselpage.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=1&t=004439#000014)

Blessings!

Brian Johnson, #5044

[LanduytG]

I have had a GV in my 95 with 4:10 for about 4 years now and love it. I always tow in OD and the trans has 160K on it and works like it was new. I also tow in double OD when pulling my car hauler. Before doing this I would get about 12mpg and running double OD I get about 14.5 plus egt's drop way down and everything is much happier. GV says not to pull in double OD but with 4:10 if you look you will see that pulling in double OD is about the same as a truck with 3:45 pulling in regualr OD. Running empty I went from 16 mpg to 18 mpg. Also whats nice is the noise reduction. Though its expensive I love and would not trade it.

Greg

[ropinfool]

I towed many miles in OD in my old truck, never had a problem. The key is as soon as the tranny starts hunting gears pull it into 3rd. I had over 120k when I sold it, original tranny, nothing done but oil changes. John