gear vendors testing

[burt]

Thanks again, I'll stop feeling like I'm playing Russian roulette every time I shift under 45mph then. If I shift it just like I would with the tranny using the clutch it shifts extremely fast and smooth. Getting my drive line modded right now. When they caution against exhaust breaks, engine braking and backing up heavy loads they mean with the gv in overdrive right? They aren't saying don't do any of those things ever again if you have installed a gv are they? Any experiences?

 

[Black dawg]

you can break the gv backing up with it off.

 

[ironworker40]

I bought a gv unit in 1989. I put it on my 1987 6.9 f-250 sc 4wd 3.55 gears . I sold the truck with 300,000 in 2000. I still see it today. Still has the c-6 trans and gv unit. Nether have ever been out of the truck it has over 450,000 on it now. I split 1st 2nd and 3rd with it , with no trouble at all. I never had any crossmember under it, hanging off the 1356 case looks weird but it does work. They get very hot. I remember when I first put it in I noticed how hot it was and called gv directly and they assured me it was okay. They are designed to be in medium duty trucks with a lot more gross weight then ours. I think up to 30,000 lbs gvw. They were also stock in mid 80s corvettes. they were 4 speed trans with gv unit controlled by the ecu to make it a seven speed manual they called it a 4 + 3. The gv's are top notch units. I changed the oil in it every 15-20,000. No synthetics.
here is an e bay link to a corvette trans and gv unit for sale for those who are interested. http://www.ebay.com/itm/1984-1988-C...NASH-COMPLETE-WITH-BELL-HOUSING-/181264604669

 

[burt]

Kinda incredible the array of views of the gear vendor. I'll believe the ones that are convenient and if I blow it up ill post up. So to those that have or have had one, how hard did or do you try not to engine brake or reverse with a load? For me it seems like there is no way around it. Thanks for reporting on how hot they get I was wondering about that. What type of oil did you use? You said no synthetic

 

[ironworker40]

I never tried to use it in reverse or down shift with it I would kick it out of od then down shift trans to engine break I used citgo oils. The diesel oil didn't burn up like the rotilla

 

[burt]

I didn't mean with it in overdrive, I just ment with it installed. It seems like people are saying its fragile in reverse and under engine braking even when it's not engaged. I could be misunderstanding. I was asking what type of oil actually, I have 80w-90 in there now cuz I had it and figured it would at least be good enough to test the unit. Dunno if it's the best for the long run tho. Btw I have called gear vendors but have been playing phone tag with them. Figure that this info will be interesting to others as well

 

[ironworker40]

OkAy. It's been a while but if memory serves me correct it takes ATF I would dump that and transfer case at the same time. It's a few quarts between the two of the so it's cheap insurance

 

[towcat]

since you want proof that these things can break, check out this thread. the location of where things went wrong is up in the Sierras about 30 mins south of Lake Tahoe on a washed out dirt road. It was a level and graded road, but a forest fire went through there and after a couple of winter rains, much of the dirt got washed out exposing the raw granite. the truck is a F350 dually wearing new A/T tires. our best guess is the GV did not like the driveline loading and unloading from a steep uphill climb at slow speed. the loading and unloading occurred with the tires catching the granite and then finding soft dirt to spin in. I like the GV still after all this, but I am realistic, any GV equipped truck must be able to convert back to it's orig system if catastrophic failure occurs. in this case, I still had the stock driveline and transfer case housing in the truck. otherwise, it would have been an expensive tow home.

http://www.oilburners.net/forums/showthread.php?60778-GV-carnage-very-ugly-pics

if you want the photo documentation that I installed it properly, I can post the thread too.

 

[vegas39]

OkAy. It's been a while but if memory serves me correct it takes ATF I would dump that and transfer case at the same time. It's a few quarts between the two of the so it's cheap insurance

Not anymore, the new spec is gear oil. I used lucas synthetic in mine.

 

[vegas39]

I didn't mean with it in overdrive, I just ment with it installed. It seems like people are saying its fragile in reverse and under engine braking even when it's not engaged. I could be misunderstanding. I was asking what type of oil actually, I have 80w-90 in there now cuz I had it and figured it would at least be good enough to test the unit. Dunno if it's the best for the long run tho. Btw I have called gear vendors but have been playing phone tag with them. Figure that this info will be interesting to others as well

I had my truck in Yosemite last weekend and did a down shift to second, then to first and forgot the GV was engaged, I heard some strange noise that I cant describe and realized the damn thing was on. I drove 500 miles home and it still works fine but probably shortened the life span a little. Oops!

 

[burt]

Wow, catastrophic failure. That's where my mind was trying not to go. If it shouldn't be exhaust braked or reversed loaded than how's it supposed to handle off roading? I was already thinking about those type of forces then applying them to trying to get unstuck with say a load of firewood and the result seems like it would look like tow cats gv. I guess it's obvious I'm putting a lot of thought into this. So Vegas, you must have your safety "brain box" Bypassed also? Otherwise it wouldn't have let you do that correct?

 

[vegas39]

Wow, catastrophic failure. That's where my mind was trying not to go. If it shouldn't be exhaust braked or reversed loaded than how's it supposed to handle off roading? I was already thinking about those type of forces then applying them to trying to get unstuck with say a load of firewood and the result seems like it would look like tow cats gv. I guess it's obvious I'm putting a lot of thought into this. So Vegas, you must have your safety "brain box" Bypassed also? Otherwise it wouldn't have let you do that correct?

No its not bypassed, I was just giving one of my brothers a demo of my fancy B&M shifter and hit the lower gears before the 18 mph cutout of the GV occured.