Changlng gears on tow vehicle

[aceinspp]

Originally Posted by gfarmcafe

Yes, it is and the more I consider things, the more it becomes a conundrum. I've always wanted to "shake things up" and do something just a little different, so I my just have to try it. Might even beautify the motor bay a little. Can you say "headers, chrome valve covers, etc, etc"? DW says go for it if I want!

Now your into a show and no go vehicle. Save the money and up grade to a newer vehicle. Next thing you know you blow the engine. If you want to do the up grade then consider rebuilding the engine also and install a torque cam, intake update, Holly carb Roller lifters and we can go on and on to make your truck a strong puller. Later RJD

[grayfox]

Originally Posted by Dabmeb

4:10 gears will kill your daily fuel mileage. 3:73 gears have always been a good choice for towing and it is a common Chev gear set


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Good call on 3:73 gears. Have had 3 Burbs in my lifetime all with 3:73's all 4wd. Made great tow vehicles back in the day. Best one for towing was my new 76 with a 400 small block... loved all 3 of ours.

[DocRob]

I've been involved in two rear ratio changes, one dodge and one chevy. Back in the day automatic transmissions had only 3 speeds so selecting the right ratio was more critical than today with 6 and 8 speed automatics. More to the point is that you will find driving with the 3.73 rear much better for occ use but if you intend to do a lot of pulling the 4.10 will be the way to go. Keep in mind that the engine noise may increase a bit due to the higher RPM on the flats and the mileage when not pulling will drop a bit. Remember to get the right speedometer so the speedometer reads right.
The other vehicle was a dodge pickup with a 3.08 rear that we changed to a 3.55 and again it made the pull much better. Have fun

[A32Deuce]

You could also check into GearVenders Over drive/Under drive. That can give you 6 forward and 2 reverse gears.

[Harkerr]

I believe 3.73 was the towing option

[AquaMan]

To me it sounds like you're just trying to relieve some of the "it sounds like this is going to blow" feeling. A gear change, some valve body work in tranny, and a reprogram to the ECM would do wonders for relatively little money. If you like your Burb, and not looking for something new, that's what I would do.

[Kenny kustom]

Originally Posted by AquaMan

To me it sounds like you're just trying to relieve some of the "it sounds like this is going to blow" feeling. A gear change, some valve body work in tranny, and a reprogram to the ECM would do wonders for relatively little money. If you like your Burb, and not looking for something new, that's what I would do.

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2008 F350 CCSB V10
2016 Sabre 36QBOK

[gfarmcafe]

Originally Posted by AquaMan

To me it sounds like you're just trying to relieve some of the "it sounds like this is going to blow" feeling. A gear change, some valve body work in tranny, and a reprogram to the ECM would do wonders for relatively little money. If you like your Burb, and not looking for something new, that's what I would do.

Exactly!

[gfarmcafe]

Originally Posted by A32Deuce

You could also check into GearVenders Over drive/Under drive. That can give you 6 forward and 2 reverse gears.

Do you, or anyone have first hand experience with this? I know it would be a radical modification, but it would bring the tranny up to more of what most are today, including the 6 speed Allison.

[AquaMan]

I had a new '99 Ford 350 with the 7.3L and though it was powerful for the day, it was a dog compared to today's diesels. I did some mods to it, but the biggest gain came from modifying the valve body and springs on the tranny and adjusting the shift points on the ECM with a program. The trans would shift harder on the upshift and hold a gear longer before downshifting. It would never hunt and peck for a gear, like in the stock form. All the mods were done with towing in mind, wasn't a "performance" thing. That said, it's still only half the truck my GMC is today.

[A32Deuce]

Yes. A friend had one on his Street Rod. 383 stroker, ran at the drag strip and drove car around the country. no problems. Turbo 400 trans. Removed tail housing, bolted on adapter, attached gear venders over/under, then had drive shaft shortened. This could be a plus if you have a two piece drive shaft. you could go to a one piece then.

[A32Deuce]

I have tossed around the idea of putting one in my 2012 SunSeeker. that would give me 10 forward speeds forward and easier on engine climbing mountains/ very large hills.

[Iwannacamp]

Hmmm. I dunno. 3k for the added trans adapter..... Put that with the current tow value.... You might buy a decent truck. JMO


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[stevejahr]

Gear Vendors does not automatically give you a bunch of forward speeds... you have to crunch the numbers and see if the resulting ratios are different. I had an overdrive like this once and gears ran 1-2-2od-3-4-4od because 3od was about 0.01 different than 4th and just not worth the effort.

You can put in all the gears you want but if you don't got the torque you just are not going to get anything done. When it is all said and done it is torque moving you up the hill and you are only going to move as fast as you have the torque to make you go.

[WolfWhistle]

Originally Posted by stevejahr

Gear Vendors does not automatically give you a bunch of forward speeds... you have to crunch the numbers and see if the resulting ratios are different. I had an overdrive like this once and gears ran 1-2-2od-3-4-4od because 3od was about 0.01 different than 4th and just not worth the effort.

You can put in all the gears you want but if you don't got the torque you just are not going to get anything done. When it is all said and done it is torque moving you up the hill and you are only going to move as fast as you have the torque to make you go.

Good point S, like many have said it is torque that is missing and there is no substitute. You are wanting to pull a grade at a particular speed that might not be realistic. I messed around with some numbers... these are estimates only.

Lowering the gear to 3:73 is about an 8% change
4:10 around 16% change in RPM.

At 60 MPH you might now be turning 1700 rpm with stock gears
3:73 will get you about 1836 rpm
4:10 will get you about 1972 rpm

You essentially would be turning about what you now do in third (assuming a 4 speed) but be in 4th.

What you get is with change, the gears are closer, so the RPM drop of increase in a gear change is less. This will keep the RPM more constant and like someone said, get it moving easier from stop.

I guess your MPG will suffer about 4% worse with the 3:73 and 8% with the 4:10.

The cost of changing the gear set, isn't going to get you any more for the Burb when you sell it.
WW

[18CrewDually]

I ran a GearVendors unit on my 87 F350 crew cab diesel.
First you do not gain another speed in reverse. Actually if the unit was engaged and you backed up it would destroy the conical clutch inside because of a one-way clutch gear inside. This is how I got my unit so cheap and had to rebuild it.
Next, the only way this unit would benefit your scenario is if you also changed out the rear ring and pinion. On my setup I ran 4.56 in the rear and with the overdrive engaged it was like I had 3.73s.

For you I would recommend either a complete reused axle from a salvage yard that you can simply swap out one weekend and see if you like it. If not, swap back. You're only talking about 4 ubolts, 4 bolts for the ujoint, 2 bolts for the shocks, parking brake cable, and the one main rear brake hose. And of course swap the wheels and tires.

Or shop around (Randy's Ring & Pinion has it all and knowledgeable employees) pick up an install kit and a new ring and pinion set. Then have it installed by a driveline shop, not Joe Shmoe Muffler shop.


I prefer older vehicles, specially if it's a single purpose vehicle like a hauler so my advice is bias. Some people don't get there's many of us that resale value or age doesn't matter. As long as it's getting the job done and it brings a smile to my face, it doesn't matter it's 20 years old.

Whatever you choose, enjoy!

[moondog2000]

My 05 Z-71 came with 3:42 gears and all I would tow is my tent trailer. When we decided to get a hard sided trailer I took my truck to a four wheel drive shop and have the gears changed to 4:10. Real big difference ,It tows so sweet,lots of power and at 60 mph the rpm is at 2600. At this rpm the oil pump in the trans has the plates locked up so there is no slippage.If I drive carefull I can get 16 - 17 on the freeway with out the trailer and with the trailer I get 10-11. The mechanic at the 4wd store is the best in the inland empire and he has been doing it for 40 yrs and he does not like synthetic oil, He says under heavy load and high heat It is too thin to provide a cushion between the metal. He recomends valvoline 80-140 GL-6 with a ford additive for the positraction. It kills me not to use synthetic oil but I trust what he says. It cost about 1000 per axel

[Dodge Guy]

Unfortunately it's not as simple as just dropping down a gear in the transmission. The axle ratio effectively changes the ratios of all the gears in the trans. So each gear will be more efficient.
4.10's will really wake it up! Your towing and around town mileage will go up.

I went from 3.55-3.90 in my Dodge van and it made a huge difference in how well it towed!

[OldCoot]

Originally Posted by Dodge Guy

...Your towing and around town mileage will go up...

Mileage will definitely GO DOWN with 4.10 gears as opposed to 3.55. The higher the gear number, the lower the fuel mileage will be.

[grayfox]

Originally Posted by OldCoot

Mileage will definitely GO DOWN with 4.10 gears as opposed to 3.55. The higher the gear number, the lower the fuel mileage will be.

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