Gear Vendors Overdrive

[SebasSF]

I have driven a 345LE with a Gear Vendors, and I can tell you that it's really nice for highway cruising. At 65 you kick it in and drop down around 500 rpm, quiet and smooth. Cruising at 70 is no problem at all. Nice to have area gears for hill climbing as well. I have on in my garage slated for install on my 300LE next month...can't wait!


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[mayco]

Ive got the Isuzu diesel with the 4sp Allison tranny. I run at 2600rpm traveling 62mph. I was concerned about the rpm when I first got the coach. But Someone pointed out on this forum that these rigs were designed when the speed limit was 55mph. Im with Dan, go slow and try to stay out of the way. Even at 62, with these disc brakes, I need to anticipate far in advance to feel safe on the highway.

[jm2]

we have a GV in our 1977, and, notwithstanding the wiggly gauges, in OD @ 62 mph, the 454 turns at about 2300 rpm. like it a lot!

only wish that the Allison converter in the TH400 would lock....

[SebasSF]

If anyone is interested, I have a GV for a Chevy/th400 that came out of a low mile1995 (or thereabouts) Land Yacht. It has been professionally rebuilt with a new cone clutch and comes will all parts. Looking for $2000 plus shipping if anyone is interested before I put it on eBay. I also have a spare parking drum brake assembly. Send me a pm.

[Punch]

Originally Posted by SebasSF

If anyone is interested, I have a GV for a Chevy/th400 that came out of a low mile1995 (or thereabouts) Land Yacht. It has been professionally rebuilt with a new cone clutch and comes will all parts. Looking for $2000 plus shipping if anyone is interested before I put it on eBay. I also have a spare parking drum brake assembly. Send me a pm.

That sounds like a good deal, for sure. But, I doubt though that it is 1995. I am willing to be corrected, but I believe that from 1994 the Land Yachts would have had the 4L80E electronic overdrive transmission with an automatic parking brake. I believe that 1993 would be as new as it could be. I had a 1994 with the later configuration, and have seen 1993's with the earlier transmission and parking brake.

A guy has to be cautious about matching these GV units to applications, and you would need to be sure of rear axle ratio (pretty sure this would be 4.56:1 in all cases), model of transmission, and type of parking brake before buying. GV technical assistance are very helpful (but busy) and given the serial number on the unit, they would be able to tell a buyer exactly what that unit is for.

I'd encourage fitting these: they are great units, and a pretty easy install.

[tjdonahoe]

Might be better to install a higher speed ring gear and pinion, like a 3.78

[SebasSF]

Thanks for the info Punch, I'm sure you are correct. The model is 3DO475 and retails new for $3695. I was going to install it myself, but my local RV shop quoted me $250...much better idea.

[Punch]

Originally Posted by SebasSF

Thanks for the info Punch, I'm sure you are correct. The model is 3DO475 and retails new for $3695. I was going to install it myself, but my local RV shop quoted me $250...much better idea.

It is probably the identical unit to mine.

If I could have found an install for $250 I would have gone for it. Actually I would have done so for $750! The front drive shaft has to be shortened 14" or so, and then all three shafts should be balanced. Iin fact GV say balance the brake drum too, but nobody could do that here). With new carrier bearings and UJ's, which a guy might as well replace at 120K miles, the driveshafts alone cost me $1100. Stuff is expensive up here, but they did do a beautiful job on it.... it's a pity it is hidden under the car!

Altogether the install itself was probably 4 hours though, and would be a lot quicker next time. The most fiddly part was extending the parking brake cable. Caused some bad language and a definite Karma deficit.

[Ryker]

JD, I just have to ask, did you take the 350 LE to Burning Man this year? I saw one somewhere around 9:00 and H or so. I went by twice to say hi but nobody there. I was at 4th and F in my 1999 Airstream Cutter. And you're right, many of us have more than one Airstream. Next year I am caravanning in my Cutter and my 1995 36 Classic with a few friends.

[SebasSF]

Posted on eBay if anyone is interested.

[KB6YAF]

I bit the bullet and had the Gear Vendors Overdrive unit installed in our '83 Airstream 310TD. I couldn't be happier. My hearing is no longer taking a beating too

Russell Decker
Olympia, WA
1983 Airstream 310 TD "RussBus"

[SebasSF]

Just remember not to use it for gearing down when going down hills, and be very gentle in reverse.

[jm2]

a PO of our 1977 Argosy 20 installed one in our coach, probably some time in the 1990s, and is still going strong.

had a minor problem with it jumping out of OD on our 2012 coast-to coast run; GV tech support correctly diagnosed an electrical issue over the phone. crawled underneath the coach at our next coffee stop, and repaired the issue in about 3 minutes.

in 3rd gear + overdrive, at about 62 mph, the 454 spins at about 2,300 rpm!

like it, at lot!

[KB6YAF]

this is a reply to my response.....my GV OD unit is not working now....a little over 2 yrs and 24k miles. NOT happy.

[J. Morgan]

A couple a few years ago I was posting that my research on these devices had not turned up good results,,,, and that an overdrive transmission might be a smarter move,,, but I was kinda shot down... just sayin....

[Keyair]

The 4L80E series GM Transmissions, are 4 speed, OD transmissions with a lockup convertor. They bolt right onto the 454, or LS and are the successor to the TH400, and TH475 transmissions.
The E dictates, they need a electronic controller... either stand alone, or linked to the TBI, or EFI on the engine.

The 4L80E is rated at 440ftlb of torque and 18,000lb GVRW
The 4L85E is rated at 460ftlb of torque and also 18,000 GVRW.

However, it is my understanding that the 85 has straight cut sun gears... like the TH475.

https://en.wikipedia.org/wiki/GM_4L80-E_transmission

[J. Morgan]

Originally Posted by Keyair

The 4L80E series GM Transmissions, are 4 speed, OD transmissions with a lockup convertor. They bolt right onto the 454, or LS and are the successor to the TH400, and TH475 transmissions.

The E dictates, they need a electronic controller... either stand alone, or linked to the TBI, or EFI on the engine.



The 4L80E is rated at 440ftlb of torque and 18,000lb GVRW

The 4L85E is rated at 460ftlb of torque and also 18,000 GVRW.



However, it is my understanding that the 85 has straight cut sun gears... like the TH475.



https://en.wikipedia.org/wiki/GM_4L80-E_transmission

Last time I checked, I think the controllers were about a thousand bucks. I haven’t ever tried one myself though.

A built up 700 R4 might work. They were pretty strong in their own right, but then it might just be an expensive failure.

[bkahler]

An alternative to the standalone controller would be to install a GM TBI controller, add the appropriate sensors needed by the controller and then have a "Tuner" (person that modifies the program inside the ECM) to just control the transmission.

I think the only sensor you would need would be the Throttle Position sensor although you might need a Manifold Absolute Pressure sensor as well. The Tuner would block or disable any code not associated with controlling the transmission.

If I ever decided to get rid of my TBI setup that's what I would do in order to keep the 4L80e. The cost for this type of control would definitely be less than $1000.

Brad

[mayco]

Originally Posted by KB6YAF

this is a reply to my response.....my GV OD unit is not working now....a little over 2 yrs and 24k miles. NOT happy.

When your GV was working, behind the Isuzu TD, what type of RPMs were you seeing at 60-62mph?

Mike

[KB6YAF]

I think the RPM's with the GV engaged at around 60 is 2300. (+ or -) Without the GV, it is around 2800 +