Planning the right M1009 for me

[Milbikes]

Some history to start my thread: I had a M1008 for a while, and really liked it, but it was just a little slow for my commute. Around town I loved it. I sold it, and bought a 1988 Chevy V30 Air Force crew cab pickup with a 6.2 and 4:10 gearing. The power and speed is sufficient for my driving style....but it is a long truck! Tough to park, hard to negotiate tight areas, and easy to hang up going over berms etc. Not a good off-road truck.

I have been wanting a M1009 for a while for several reasons: The 6.2 engine, the ability to carry me and my family and dog, short wheelbase for better off-road ability. But the axles and gearing prevent pulling my loaded M101A2 trailer.

My thoughts about modifying a M1009 are one of two choices. First is to get a set of 4:10 axles like my pickup has, and swap them in. That should give me the cruise speed I need, plus much better towing and off-road ability.

The other option is M1008 axles with a 700R4 transmission. This might give me the best of both worlds...great axles, And good highway speed. But, I am not a transmission expert, so I am wondering what the knowledge pool thinks? Thanks for any tips, and sorry for the long rambling post. The exhaust CO leaking into the cab of the Ford plow truck may be affecting me.... H.

 

[dstang97]

Is the 3+3 rust free? Looks good. I would leave the th400 and get 3.73 or 4.10 one tons.

 

[1ton cucv k5 turbo]

in your line of thinking, getting a M1009 and swapping axles from a M1008 would be ideal, as well as swapping the 400 for a 700r4, both transmissions basicly have the same gears, except the 700r4 does a have a lower 1st, and the added 4th gear. keeping the 456 gears shouldnt be an issue provided that you dont add oversized tires. the only issue you will have to resolve is mating the 700r4 to the NP208. you may be in luck, and just swap the trans and transfer case from your 3+3 to make the changeover simpler.. than all you have to contend with is the driveshafts which wouldnt be difficult.


i already have a M1009 with the M1008 axles... ( it is awesome...) and also debating the changeover. as just going with a Gearvendor overdrive. but becasue of my short wheelbase, and lift... i dont think i will have the room... and will just have to put in a 700r4...

 

[GPrez]

With the M1009 towing a M101A2 I would think the gear needed would be 3.42 or at worst 3.73 to keep the RPM's in check at highway and be able to tow well unless you are lifting and putting bigger tires on. I've towed my M101A2 with 1,000 lbs. on the stock 3.08's and it does fine plus I have 33" tires on. Unless your going to severely overload the trailer and/or put big tires on I would go 3.42. Now if you were planning to tow your car hauler then 4.10 maybe, but I wouldn't recommend that with a short wheelbase M1009.

If you go with a M1008 I would go with a Gear Vendors Overdrive. That is what I am going to do with my M1028 I pick up from GL next week. When I tried to add up the costs of all the different options (700R4 swap, Ratio Swap, ect.) the costs and amount of work associated with each all add up to darn near the $3K for the gear vendors for me. The gear vendors seems to be a simple install as well.

 

[allenhillview]

I'd like to follow a Gear-Vendor thread, where one adds support to the rear or that thing after install in 1008.

I'd love to have but just can't get by the fact of the length and no support on that aluminum case/cases.

I've read some threads but have missed or not seen any support bracket.

Didn't want to Hi-Jack,sorry in advance.

 

[DriverSideImpact1008]

Like GPrez said swapping in axles with 3.42 or 3.73's would be good for everyday cruising and pulling the M101.

70's Blazers most often had 3.73's in the stronger 12 Bolt rear axles with Dana 44 fronts (30 spline axles).
80's K5's had everything from 2.73 to 3.73. I think 3.08 and 3.42 were the most common gear ratios. 89-91 Blazers had 30 spline 10 Bolt axles.

 

[Milbikes]

My 3+3 is fairly rust free, just a little in the rockers, and one bed fender lip.

If I got a M1009, no matter what axles/gears it had, I wouldn't use it for heavy towing....gotta respect that short wheelbase. I would like it to be able to tow the M101A2 with an Alaskan type (hard sided popup) camper and a lot of gear in it, both on and off road. I know 4:10's would do it, although limiting me to 55 or 60mph tops. The 3:73's might be better? My 6.5 diesel Suburban has 3:73's and when I tow a larger trailer, I wish for 4:10's. H.

Picture of Alaskan camper on M101 borrowed from the web.

 

[DriverSideImpact1008]

I know 4:10's would do it, although limiting me to 55 or 60mph tops. The 3:73's might be better? My 6.5 diesel Suburban has 3:73's and when I tow a larger trailer, I wish for 4:10's.

The Suburban has a 4 speed trans with overdrive. The 1009 has the 3spd so the RPM's will be higher, and better for towing. The Suburban w/3.73 @65mph is 1900rpm VS a 1009 w/ 3.73 @65mph: 2600rpm
I know a lot of guys with 1008's put 4.10's in them and are happy with the results, however, your top speed would be about 65... 70mph and you're over 3000rpm.

Here's a gear ratio/RPM calculator:
Engine RPM Calculator

 

[southdave]

The Suburban has a 4 speed trans with overdrive. The 1009 has the 3spd so the RPM's will be higher, and better for towing. The Suburban w/3.73 @65mph is 1900rpm VS a 1009 w/ 3.73 @65mph: 2600rpm
I know a lot of guys with 1008's put 4.10's in them and are happy with the results, however, your top speed would be about 65... 70mph and you're over 3000rpm.

Here's a gear ratio/RPM calculator:
Engine RPM Calculator

Your geary thingy? I am confused I have nv4500, according to it with 31" tires and 4.56 , I am pulling 2300 rpm at 70? I am thinking I did somthing wrong?

 

[DriverSideImpact1008]

Did you use the top calculator? If you set it to 31" tires at 70 MPH, and you didn't change the axle ratio (the default is 3.08 ), and then you read the RPM for "Manual" it would be 2337 rpm...


The overdrive ratio in the NV4500 0.73 or 0.75?

I use the bottom calculator (The one where you enter in the Axle Ratio, Tire Height, MPH, and Trans Final Gear Ratio). And with your specs I calculated 2500rpm.

And a calculator on Randy's Ring and Pinion website gave the same measurement.

 

[southdave]

think it is .71 but 2200 seems to be the sweat spot with these engine I assumed I was around 2800 rpm I am just allittle plasently supprised thanks