Alright guys how many of you know how to float your gears in your 5 or 6 speed cummins? 

Recently I tried it for the first time and it’s surprisingly easy to do no grinding and no resistance when shifting. I also tried it in my Jeep Wrangler with lil trouble. 

I’ve found quite a few older posts regarding the syncros suffering from floating gears but is that only because people aren’t doing it right? 

 

The reason being is that my stock clutch is slipping. And I’m trying to buy as much time as possible. 

 

Any advice or personal experience would be greatly appreciated!!! 

As long as you can do it without forcing the gear you should be OK. Still not a suggested method but I understand buying time.

What do you mean by floating gears? No clutch? Shifting while applying throttle? 

21 minutes ago, Marcus2000monster said:

What do you mean by floating gears? No clutch? Shifting while applying throttle? 

@Marcus2000monster Correct no clutch once I have the truck moving. If you are smooth enough it literally goes into the gears like butter. Only when down shifting do I need to tap the throttle to get it into gear. 

1 hour ago, Mopar1973Man said:

As long as you can do it without forcing the gear you should be OK. Still not a suggested method but I understand buying time.

@Mopar1973Man what are the cons other than the syncros? If it’s detrimental to my tranny I will just bite the bullet sooner

2 minutes ago, JDHudsn said:

@Marcus2000monster Correct no clutch once I have the truck moving. If you are smooth enough it literally goes into the gears like butter. Only when down shifting do I need to tap the throttle to get it into gear. 

@Mopar1973Man what are the cons other than the syncros? If it’s detrimental to my tranny I will just bite the bullet sooner

OH I gotcha now. I have done that several times. You have to be at pretty low rpms it seems like. 

If you have driven larger truck with Eaton fuller you find out there do not have syncros at all. So it a float shift you do in those trucks. Its a matter of letting the tension off the gear matching RPM for a brief second pull it out then let the RPM's fall and slip it back in as the RPM's fall. This would be an upshift. A downshift is a bit tricky for newbies. You would match the RPM slip it out of the gear your in tap your throttle to gain RPM's to match and slip back in. 

 

That all I know of. When your float shifting the very minor amount of RPM offset will pull on the syncros but if your matching really close then I really doubt any harm will happen. Basically using the syncros like a clutch trying to slow the gear to match. Again if your RPMs are right then really there shouldn't be any wear. 

1 minute ago, Marcus2000monster said:

You have to be at pretty low rpms it seems like. 

 

Yes. That is the key to doing this right. In larger trucks, you can bang out the first 5 gear in less than 100 yards. 

 

4 minutes ago, Mopar1973Man said:

If you have driven larger truck with Eaton fuller you find out there do not have syncros at all. So it a float shift you do in those trucks. Its a matter of letting the tension off the gear matching RPM for a brief second pull it out then let the RPM's fall and slip it back in as the RPM's fall. This would be an upshift. A downshift is a bit tricky for newbies. You would match the RPM slip it out of the gear your in tap your throttle to gain RPM's to match and slip back in. 

 

That all I know of. When your float shifting the very minor amount of RPM offset will pull on the syncros but if your matching really close then I really doubt any harm will happen. Basically using the syncros like a clutch trying to slow the gear to match. Again if your RPMs are right then really there shouldn't be any wear. 

 

Yes. That is the key to doing this right. In larger trucks, you can bang out the first 5 gear in less than 100 yards. 

 

I need to figure out the exact matching rpms thru all 6 gears and then I’ll be like a straight up trucker! Lol.

4 minutes ago, Marcus2000monster said:

I need to figure out the exact matching rpms thru all 6 gears and then I’ll be like a straight up trucker! Lol.

If you’ve been driving the truck for a few years you might be better at it than you think! At least I feel like I am. None of the gears need to be forced in. I shift around 2K rpms when up-shifting

In not about RPM matching and about the feel. Once you have done it enough you get the picture. It's about gaining the slack on the gear to slip out and letting it fall and slip back in. You'll find driving this way you shift gears early. Too high in the RPM will trap the gear and make it hard to get out and back in. Too low can be just as bad too. There is no magic match RPM either each truck and transmission is a bit different and behaves differently. I've driven Eaton fuller 8 speeds (Freight shaker) and Eaton Fuller 10 speeds (KW)

 

One of my favorite fire trucks... Cummins Big Cam 400 with Eaton Fuller 10 speed. We've converted to a water tender over the years looks way different now.

@Marcus2000monster when shifting you should have s slight pause in neutral before going into the next gear

30 minutes ago, JDHudsn said:

If you’ve been driving the truck for a few years you might be better at it than you think! At least I feel like I am. None of the gears need to be forced in. I shift around 2K rpms when up-shifting

Only had my truck for a year and only floated gears like 5 times lol.

@Mopar1973Man based on my application what are your thoughts on this clutch?

 

https://www.summitracing.com/parts/sbb-sdd3250-5k

 

 

Contact Peter directly at South Bend Clutch ask him. I would avoid ceramic clutches it will eat the pressure plate.

 

 

Edited May 8, 20186 yr by Mopar1973Man

Floating gears on transmissions such as these is highly ill-advised.  Even though you "think" you're closely matching gear/rpm speeds, what you're really doing is prematurely wearing out the blocking ring clutch and soft teeth because you're never as close as you think you are.  When transmission rebuilds are in excess of $2000 - $3000...and most replacement parts are only available hecho en China these days...  But hey, to each is own.

 

Also, why would you feel that floating gears is going to help limp along a slipping clutch?  You're not buying any time by not engaging the clutch in order to shift properly.  You're buying time by keeping your foot out of the throttle so the clutch doesn't slip anymore.

2 hours ago, KATOOM said:

  When transmission rebuilds are in excess of $2000 - $3000.

Geez where are you getting your rebuilt at? When I broke the mainshaft it was 1800 for all new bearings, syncros, and replaced 5th gear because the inter hub lost its hard facing. I could of had it for 1400 if I didn't break the mainshaft and wore out 5th gear.

Edited May 8, 20186 yr by Mopar1973Man

Get a 6 speed. 3k is where a good one starts and thats without broken hard parts. $$$$$$$$$$$$$$$$$$$$$$

1 hour ago, dripley said:

Get a 6 speed. 3k is where a good one starts and thats without broken hard parts. $$$$$$$$$$$$$$$$$$$$$$

Man I should of grabbed a spear 6spd for 1500 when I had a chance had 180k on it and from 01 with bigger mainshaft. 

NV5600 is the magic word. Soon as you say 6 speed it goes up in price fast. 

 

Quote

The NV5600 is a Heavy Duty close ratio 6-speed manual transmission that was used in 1998-2005 Dodge RAM 2500 and 3500 Series ¾ ton and 1 ton Trucks with the 5.9L Cummins Engines.

1

 

Quote

The New Venture Gear 4500, commonly called NV4500, is a 5-speed manual transmission manufactured by New Venture Gear and used in General Motors and Chrysler products from 1991–2007.

 

 

Then...New Venture (New Process) closed down after 124 years of service.

 

Quote

After 124 years in business, New Venture Gear started to close in the week of August 20, 2012, and was fully shut down by the end of the week.

1

 

Since 6 speeds only made for Dodge and very small year range the part is hard to come by. 5 Speeds are plentiful because of the usage in Chevy as well Dodge trucks and for a much wider range of time. There are more remanufactured parts for the 5 speed today than the 6 speed. 

35 minutes ago, Dieselfuture said:

Man I should of grabbed a spear 6spd for 1500 when I had a chance had 180k on it and from 01 with bigger mainshaft. 

something different from what came in the later versions? 

bigger than than the 1 3/8 shaft?

 

I lost 4th in the oe around 250k and bought one from a junk yard out of an 02 with 51k on it. It is currently in the truck 200k later. I would like to send that one off and have it rebuilt. Hopefully soon. I would not mind having a working spare even if it has 250k on it.

23 minutes ago, Mopar1973Man said:

 

Since 6 speeds only made for Dodge and very small year range the part is hard to come by. 5 Speeds are plentiful because of the usage in Chevy as well Dodge trucks and for a much wider range of time. There are more remanufactured parts for the 5 speed today than the 6 speed.

I went for a manual because I had heard stories about the autos being weak. Got sold on the 6 speed at the dealer. I had a Tim Allen moment when they started talking HO engine, 6 speed tranny, the testosterone started pumping. My heart sank when NV shut the doors. 

 

The other thing that got me years after the purchase was the folks I met that complained about there autos failing. All this while I was looking  18k to 20k pound trailers they were pulling. They just did not get it. And after their auto failed it was back to the dealer for a stock rebuild.

 

I almost left this out. I still love my 6 speed. A bit more difficult to get thru the gears for hot rodding, but I can still do it when necessary.

Edited May 9, 20186 yr by dripley

@dripley There's a company out of Texas, Super Stick Transmissions, who specialize in quick shifting NV5600's, and warranty their stock rebuilds to 700 hp.  Just food for thought.

17 minutes ago, dripley said:

something different from what came in the later versions? 

bigger than than the 1 3/8 shaft?

In 2001 they went from 1 1/4 to 1 3/8 so as far as I know 1 3/8 was as big as they got. But still  $1500 that I didn't want to spend at the time...hopefully I'll never regret it. But I also don't want a garage full of spear parts for just in case, done that before and then I'd sell whatever it was for and usually ended up giving most of it away with that vehicle. Trying not to make that mistake again.