Overdrive choice?

[mark '87 930]

Aside from Gearvendors, I saw this on the web:
http://www.odspares.com.

Has anyone tried these units in behind an sm420? they are standalone but wouldn't bolt up behind the sm420 like the GV would. It is a standalone unit you can put pretty much anywhere you like along your driveline (cutting your driveshaft and bolting it to this obviously).

I dont' want to change the transmission as i like manual, and i dont' want to bother with shifter relocation/bellhousing work... the GV is very expensive and this comes in at about $1800 all in, delivered to my door.

[mknittle]

I think those are small british units.

[mark '87 930]

yes, but would they work? I don't plan on having a huge power house and would be lucky i have 200hp now..

[mknittle]

Originally Posted by mark '87 930

yes, but would they work? I don't plan on having a huge power house and would be lucky i have 200hp now..

That company is over seas the shipping would cost as much as the overdrive.besides the cost of custom parts to adapt it if you can as it is likely metric
a better choice with that low horsepower would be a T5 5speed.

[mknittle]

Originally Posted by mark '87 930

yes, but would they work? I don't plan on having a huge power house and would be lucky i have 200hp now..

That company is over seas the shipping would cost as much as the overdrive
a better choice with that low horsepower would be a T5 5speed.

[beanyard]

Originally Posted by mark '87 930

Aside from Gearvendors, I saw this on the web:
http://www.odspares.com.

Has anyone tried these units in behind an sm420? they are standalone but wouldn't bolt up behind the sm420 like the GV would. It is a standalone unit you can put pretty much anywhere you like along your driveline (cutting your driveshaft and bolting it to this obviously).

I dont' want to change the transmission as i like manual, and i dont' want to bother with shifter relocation/bellhousing work... the GV is very expensive and this comes in at about $1800 all in, delivered to my door.

I know I have tooted my horn a bunch about the optional Borg Warner setup they used with the three speed trans. That is what I have and I love it. The overdrive is automatic and the three speed part is manual.
Posted via Mobile Device

[mknittle]

Originally Posted by beanyard

I know I have tooted my horn a bunch about the optional Borg Warner setup they used with the three speed trans. That is what I have and I love it. The overdrive is automatic and the three speed part is manual.
Posted via Mobile Device

I forgot about those!

[arturo7]

Have you considered swapping out your rear end gears? 3.39s are available from several vendors. If this isn't enough, you could swap out the whole axle for a Ford 9", for which there are more gear options.

Keep in mind, the Muncie SM420 has an incredibly low granny gear. You're not giving up so much by going with taller gears. In fact, it is likely that you could still end up with a wider gear range than you could get with a 5 speed.

FWIW, I'm planning the Muncie + 3.39s. I figure at highway speeds my RPMs will be in the mid to 2,000s.

[mark '87 930]

Actually, I have a set of Patrick's 3.38 gears that i will be putting in this winter. I know that first gear on that transmission is not really used (by me right now) because it is so low. I'll likely be in the mid 2000's doing around 60mph which is fine.. I was hoping to be closer to the 2k range or just under. That's why i'm asking the question. The GV unit is a lot of money and I don't see any financial gas from a gas consumption perspective, or at least enough to say that it's worth it. I've already got about $500 into the rear diff gears, so if there was a straightish swap of a transmission or OD unit, I would like ot consider that. The T5 route means a cross member, shifter relocation hassles...etc.

[mknittle]

Originally Posted by mark '87 930

Actually, I have a set of Patrick's 3.38 gears that i will be putting in this winter. I know that first gear on that transmission is not really used (by me right now) because it is so low. I'll likely be in the mid 2000's doing around 60mph which is fine.. I was hoping to be closer to the 2k range or just under. That's why i'm asking the question. The GV unit is a lot of money and I don't see any financial gas from a gas consumption perspective, or at least enough to say that it's worth it. I've already got about $500 into the rear diff gears, so if there was a straightish swap of a transmission or OD unit, I would like ot consider that. The T5 route means a cross member, shifter relocation hassles...etc.

First gear in the 420 isn't Synchronized so it won't be easy to shift from second to first.

I am not putting it down. that is just the way it is! I have one in my jeep for the lowest first gear in any stock four speed tranny.

[northerngmc]

Originally Posted by mark '87 930

Actually, I have a set of Patrick's 3.38 gears that i will be putting in this winter. I know that first gear on that transmission is not really used (by me right now) because it is so low. I'll likely be in the mid 2000's doing around 60mph which is fine.. I was hoping to be closer to the 2k range or just under. That's why i'm asking the question. The GV unit is a lot of money and I don't see any financial gas from a gas consumption perspective, or at least enough to say that it's worth it. I've already got about $500 into the rear diff gears, so if there was a straightish swap of a transmission or OD unit, I would like ot consider that. The T5 route means a cross member, shifter relocation hassles...etc.

Do you have a US rear diff or Canadian rear diff?

I swapped my 3.90's in my 59 this past summer to the 3.38's from Patrick's. Their kit is designed for the US rear diff. The only difference seemed to be the bolt circle diameter on the ring gear. The US version is about an 1/8 " smaller in diameter. I had to take a grinder to the center housing and slightly elongate the holes. I did not know this until I was into the job. I talked to a couple of other Canadians who said they also did this. Just thought you might like to know before you tear into your 55T rear diff.

[mark '87 930]

Thanks for the, the truck is actually originally from Oklahoma, so I'm pretty sure that it would be a US rear diff, however, if it is not, then I will ensure i have a grinder handy.

Going back to the OD ideas, I read that a mopar 1-883 transmission is a good bolt in, is that true? I do like the sm420 as it sounds like it's rugged and will not be easy to break. I don't race and use the truck driving ont he hwy 95% of the time. I do pull my boat to and from teh marina twice a year with it, but that's only 2 miles away..

[1project2many]

I was hoping to be closer to the 2k range or just under. That's why i'm asking the question. The GV unit is a lot of money and I don't see any financial gas from a gas consumption perspective, or at least enough to say that it's worth it.

I agree. Watch Ebay and Craigslist for an old "Brownie" or Spicer two speed auxilliary gearbox.
http://www.ebay.com/itm/1954-GMC-Mod...sories&vxp=mtr

Or maybe locate an old three speed trans and install it backward behind your current trans using third gear for 1:1 and engaging second gear for overdrive. Chances are you can get one for $200 or less and the amount of fabrication work may not be much more than the imported box.


FWIW with that large rear ratio change I'd probably try the new gears before committing time and big money into the OD unit. If you want to reduce RPM more you might be able to switch to a taller, narrower tire. Air resistance around a rolling tire accounts for a large part of consumed energy when driving.

I know I have tooted my horn a bunch about the optional Borg Warner setup they used with the three speed trans. That is what I have and I love it. The overdrive is automatic and the three speed part is manual.

Just a cautionary note to anyone considering one. Back in the day many people considered them a "weak" unit. Originally they were wired so the ignition circuit was disabled during a shift to prevent engine torque from damaging them. I know a few guys that have broken the OD planetary behind a healthy smallblock by not utilizing the OEM safeguards.

There's also a "4+3" transmission which was a Super T10 4 speed with an hydraulic OD section added by Doug Nash engineering. It was factory equipment in Vettes in the early to mid '80s and although it's also considered a weak unit by performance enthusiasts it could be used in an empty truck by a careful driver.
http://www.5speeds.com/dne.htm

[mknittle]

this is getting complicated. And heavy! To avoid relocating a shift lever the whole drive train is getting relocated!
I would just run the 420 for now and save up for a 5 speed.
planitary overdrives create more drag than a 5th gearcausing loss of milage.
There is no point in having a higher gear if it uses the same amount of fuel to turn it!

[1project2many]

planitary overdrives create more drag than a 5th gearcausing loss of milage

Any OD creates more drag than direct drive. Ideal solution is 1:1 transmission output and numerically lower rear gears with enough underdrive ratios available to get the load moving.

[mknittle]

Originally Posted by 1project2many

Any OD creates more drag than direct drive. Ideal solution is 1:1 transmission output and numerically lower rear gears with enough underdrive ratios available to get the load moving.

Yeah But planatary has more drag than one gear turning another.A good planitaty drive uses six gears with eight contact points. a fifth gear has one.

Ideal solution is 1:1 transmission output and numerically lower rear gears with enough underdrive ratios available to get the load moving.[/quote]
Like a 18 speed road ranger 17th is direct and 18th over and some have a double over 17th and 18 are over.

[arturo7]

Another option would be to keep the Muncie and swap in a Ford 9" rear axle. You can use gears as tall as 3.0 and beyond. Not that you'd want to go too far...

[Russell Ashley]

Here's what you need. Seems a little high priced though.

http://www.ebay.com/itm/1958-1959-19...d7acde&vxp=mtr

[beanyard]

Originally Posted by Russell Ashley

Here's what you need. Seems a little high priced though.

http://www.ebay.com/itm/1958-1959-19...d7acde&vxp=mtr

That is what I am running in my truck and it is AWESOME. My version might be might have minor differences but I am not sure.
Posted via Mobile Device

[_Ogre]

Originally Posted by Russell Ashley

Here's what you need. Seems a little high priced though.

http://www.ebay.com/itm/1958-1959-19...d7acde&vxp=mtr

a little high indeed, plus he ships us only.

your modding the whole drive train to save the shifter?
i just see the dollar signs adding up and up.
i'd do the t5 or the newer 6 speed with double od

[mark '87 930]

realistically, i have abou 12" that i can relocate the shifter back towards the seat. i'll have to look at all options and see if that works. i do want to stay with a manual tranny, and would like OD. what is the max power a T5 can take? weren't they mustang transmissions?

[mknittle]

This may help
http://www.5speeds.com/t5/

http://www.inliners.org/Jack/T5tech.html This is the way i would go if I ran my 270 inline six!

http://www.superchevy.com/tech/sucp_...d/viewall.html

http://www.gforcetransmissions.com/tran_gt-5.asp

[1project2many]

what is the max power a T5 can take? weren't they mustang transmissions?

There were many different T5 versions. I made quite a bit of money over the years rebuilding or replacing stock versions. They'd often fail with less than 100k on the odometer. They'll burn up in 4 cyl trucks, V6 cars, and in performance applications. The strongest models are the "World Class" transmissions but not long after they started showing up in OEM applications, the OEMs dropped the T5 in favor of stronger transmissions. Yes, a Mustang is one source for the T5 but the input shaft is different, the case is different, the shifter is different, and the tailshaft is different so practically speaking it's not a viable option for a Chevy powered vehicle. S10 trucks and Astrovans are common applications but even these vehicles were switched to the NVG3500 when the TBI engines were replaced with higher output PFI versions. Today the T5 is a cheap transmission that is often discussed for swaps. Maybe it's due to the experiences I've had through the years but there are very few applications for which I would consider one.