Overdrive unit??

[leadtrombone]

Has anyone actually used something like this http://www.drivetrain.com/parts_catalog ... rans..html

Looks like it might be something to look into when one intends on towing or doing lots of highway miles..

Just wondering if this would be a worthwhile upgrade to look into in the future...

At near 3g's it would be expensive though..

[mdmead]

I could see the value of having an underdrive model, if you were towing a lot of heavy loads and needed some extra gear choices. I don't see where it would ever pay for itself in fuel savings as an overdrive though. (Maybe back before overdrive transmissions were available, but not today.)

[Kidhauler]

I could see using it for a overdrive. With the 3:73 gears you are turning more rpm on overdrive at highway speed than the van I had with either 3:23 or 3:43 gears. I got 4-5mpg better in the vans that didn't have the towpack. $3000 is a little too steep of a price tag for me as I don't think I would save that money back in the life left in my van. But if I was to get a new van I would look at it.

[1Gary]

TCI auto makes a 6 speed which is also in the 3's.I have heard of Motor Homes using the Gear Vendor's set-up.In my case,it would be a add-on to my 400 which is stout enough to handle the wt of the MH and could use the O/D section of it for "some" better gas mileage.But like everyone is saying,"wow",3 grand.

[robertg]

i'm really curious to find out about tci's 6 speed. everything i've seen and read that it is special parts in a 4l80e case.

[mdmead]

TCI auto makes a 6 speed which is also in the 3's.I have heard of Motor Homes using the Gear Vendor's set-up.In my case,it would be a add-on to my 400 which is stout enough to handle the wt of the MH and could use the O/D section of it for "some" better gas mileage.But like everyone is saying,"wow",3 grand.

I don't have a tach on my motorhome (yet!, it is on my 'to do' list), but I don't think the overdrive would do me any good. Granted, I have a OD automatic in it now anyway. But again, an underdrive version would be helpful. I find when towing our car behind, I could use a gear between 2nd & 3rd when climbing over the local mountain passes. 2nd gear that poor 460 is tached out and I have to back off the speed on the long climbs, which puts me down around 45 mph. If I could hold 3rd gear, it will run all day at 60-65 mph. With a gear choice in the middle, I could probably run up the mountain at 55.

Instead of an aftermarket overdrive, or even the TCI 6-speed, I think the answer is to wait for one of GMs 6L80E or 6L50E in the boneyard and use an aftermarket controller to run it. Even this is going to be a pricey option, but can maybe be done for less than $3K.

(Or just keep buying the extra gas. I think this is the cheapest route!)

[1Gary]

Matt-my Winniebago gets with no head wind flat driving land 8 to 10 MPG.I promise if I could figure a way to get 16 MPG to 18 MPG,I promise I would have someone take a picture of me kissing both the front and back bumpers wearing Peter's white dress.These motor homes are NOT cheap to run down the road.Mine has 4.11's in the rear end and is 8,000bls dry and is a 350 SBC.