M1009 to 700R4 and NP241

[alpine44]

After driving my M1009 (see modifications in sig line) for a while and having to redline the engine on the highway, I decided to drop in a 4 speed 700R4 with a NP241 transfer case. With this combination the highway speeds will be in the sweet spot of the torque curve. 2000 rpm will yield 73 mph (currently 48mph) and 2200 will bring it up to 79 mph (currently 52 mph). I already have the turbo components to compensate for the performance loss here at 6000 feet and add a little torque at lower rpm.

I reviewed the various threads about 700R4 conversion, but the following questions remain:

• What is the best transmission dipstick for the M1009? (the one on the 700R4 that I am going to build needs to be replaced)
• What components should be upgraded on a 1992 model year 700R4?
• Is a slip yoke eliminator for the NP241 money well spent or should I just shorten the existing rear drive shaft? (i will go with a new CV shaft in the front)

And last but not least:

• Does anyone have the elusive TV-cable bracket for sale?

Thanks in advance.

 

[cucvrus]

RED Line an M1009. What were you hitting 120 MPH. I drove these as fast as they would go and never hit the red line. 308 gears are the same gears I had in several stock GM trucks over the years. Never heard of red lining a Blazer M1009. I drive a M1008 4:56 gears everyday and it may be at red line on the Interstates. But I doubt it. It has been doing it 6 days a week the last 12 years. That is over 70 K miles since then. It has 110 K on it now and had less then 30 K on when I bought it. I never heard of Red line in a stock Blazer.

 

[alpine44]

Should have put "redlining" in quotes or used the term "way out of the sweet spot". With the 4.10 gears I need ~2900rpm to make 70 and the speed limit is 80 here on most highways. Even though the engine did not blow up (yet), the noise is insane and the efficiency definitely not as good as it could be if you look at the torque curve.

Anyway, I bought the 700R4/NP241 today and my M1009 WILL get a fourth (OD) gear. There are plenty of people out there that are happy with this conversion.

 

[alpine44]

Does anyone have constructive suggestions or a lead on the TV-cable bracket?

 

[Recovry4x4]

Over the years I've pulled probably 15-20 of the TV cable linkages out of the pick a part yards. Pickins have been slim lately. Probably been a year since I got my last one. I would hit every yard within driving distance and don't forget to check vans. Any trans should be freshened up before install and the builder should know what components are best upgraded. The yard I've had most success with now lists vehicles on their website as they enter the yard. I keep an eye on that!

 

[Chaski]

Does anyone have constructive suggestions or a lead on the TV-cable bracket?

eBay... or a pick-n-pull yard.


As far as what upgrades to go with.
Sonnax "smart shell" (sunshell)
Rebuilt torque converter with new lockup friction material.
Larger servo (corvette or 4L70E)
More frictions
Get a kit to modify the governor, most likely a "diesel" one will shift too early with 4.10 gears, and a v8 gas one may be just right or a little early.

 

[alpine44]

Thanks for the suggestions.

I am watching ebay for the TV-cable bracket. (There is one listed for over $300 and it does not even come with the rod that connects cable to IP lever)

Upgraded sunshell, better 3/4 friction discs, Corvette servo, shift kit, and a GM33 torque converter are already on my list. Are there any other important upgrades or tips I should consider? I will rebuild the 1992 700R4 and NP241 myself.

For the governor, I will order the weight and spring kit and experiment with it as the governor can be taken out and reconfigured with the tranny installed in the truck.

 

[Chaski]

Thanks for the suggestions.

I am watching ebay for the TV-cable bracket. (There is one listed for over $300 and it does not even come with the rod that connects cable to IP lever)

Upgraded sunshell, better 3/4 friction discs, Corvette servo, shift kit, and a GM33 torque converter are already on my list. Are there any other important upgrades or tips I should consider? I will rebuild the 1992 700R4 and NP241 myself.

For the governor, I will order the weight and spring kit and experiment with it as the governor can be taken out and reconfigured with the tranny installed in the truck.

For what it is worth, when my 700r4 decided to turn one set of planetary gears into metallic paste in the bottom of the pan it had one of "the beast" sun shell in it. It is a strong product, but the sonnax "smart shell" uses a Torrington bearing, and some other magic to take the thrust load away from the planetary set. I have run with a "smart shell" for a couple years now with no issues. Just something to be aware of.

Also get a larger boost valve.

Is there some reason you are going with new driveshafts? At least with the np208 I thought the length difference between a th400 and an 700r4 was less than half an inch. A slip yoke eliminator would be cool, but I always like the option of running a junk yard stock driveshaft if I damage one.