2INSANE
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Overview
Please give many thanks to the 10+ SS members for giving me the motivation to create this thread. Chuckg, 4sdair, forest522, computer54, dezertdemond, Dsilverline, Chevymike, ssdvc, TheMod, Mullaney, royalflush55, 1love, Sharecropper…
By popular demand! This is a REAL M1009 1984 Chevy K5 Blazer 700r4 swap. This swap has been done many times, talked about 1 million times and beat to a dead horse a trillion times! However, in this thread, unlike other threads, I will be giving step by step detailed instructions with pictures and condense hundreds of threads worth of knowledge into one. This thread will be the one stop M1009 700r4 swap info thread any m1009 owner or others would ever need regarding this topic.
This 27 spline 700r4 and 27 spline np208 came out of a 1985 Chevy Suburban that had a 6.2L Diesel. Pre 1986 700r4’s have a mechanical controlled valve body that does not require electronics for the lockup.
Why am I swapping from the strongest 3 speed th400 to a weaker 700r4?
Read this!
https://www.thedieselpage.com/article/lee700r4-1.htm
Pros:
Cons:
Am I missing anything?
So now you know all the pros and cons…
Let’s giterdun!
Parts List:
Parts list continued…
Please give many thanks to the 10+ SS members for giving me the motivation to create this thread. Chuckg, 4sdair, forest522, computer54, dezertdemond, Dsilverline, Chevymike, ssdvc, TheMod, Mullaney, royalflush55, 1love, Sharecropper…
By popular demand! This is a REAL M1009 1984 Chevy K5 Blazer 700r4 swap. This swap has been done many times, talked about 1 million times and beat to a dead horse a trillion times! However, in this thread, unlike other threads, I will be giving step by step detailed instructions with pictures and condense hundreds of threads worth of knowledge into one. This thread will be the one stop M1009 700r4 swap info thread any m1009 owner or others would ever need regarding this topic.
This 27 spline 700r4 and 27 spline np208 came out of a 1985 Chevy Suburban that had a 6.2L Diesel. Pre 1986 700r4’s have a mechanical controlled valve body that does not require electronics for the lockup.
Why am I swapping from the strongest 3 speed th400 to a weaker 700r4?
Read this!
https://www.thedieselpage.com/article/lee700r4-1.htm
Pros:
- The 700r4 has a lower 1st gear of 3.06 vs the Th400 1st gear of 2.48. The lower 1st gear will drastically help crawl up or down hills and obstacles. Even reverse gear on the 700r4 is lower with a 2.29 ratio vs the Th400’s 2.0 ratio.
- The 700r4 has a high 4th gear of .75 vs the Th400’s 3rd gear of 1:1, which is the same ratio of the Sm465. This added 4th gear will drastically improve motor life by lowering rpm’s, give better mpg and faster hwy speeds.
- 700r4’s have many upgrade options that can make it stronger, if not better then the Th400 pending on ones budget. In fact, the 700r4 is commonly used in drag racing cars that push 600 hp and 600 torque. My current budget is based off of a 27 spline build vs an optional upgrade to the 30 spline in a 700r4. My goal is to run it until it blows and upgrade the spline and other items later as my budget and warranty allows.
- The pre 1986 700r4 is controlled by a TV cable, not vacuum or electronics. My plan is to delete the M1009 vacuum system which includes the vacuum lines, vacuum pump and vacuum throttle position valve on the injection pump. In place of the old vacuum pump, I am going to put a 6.5 diesel oil pump gear drive with the tachometer sensor on top for the rpm gauge.
- Ever since I changed the axles with 4.56 gears back in 2009, I have always wanted an extra gear. With 4.56 gears and the old 6.2 my top speed was 55mph and about 16-18mpg. With the 6.5 turbo my top speed is the same 55mph but my mpg dropped to about 15-17 mpg. I do not want the electronics of a 4L80E and do not want a clutch Nv4500 to burn when crawling up hills or obstacles. Since 2009, I have only driven my M1009 37,000 miles. Most of those miles are interstate and hwy from the house to the trail head. I do not plan on towing more then 2,000 pounds. I think this swap will suit me well for the time being. My chances of blowing up this 700r4 before the 3 year/30,000 mile warranty this 700r4 is high. If it does blow while still in warranty, the additional cost to add the 30 spline will be minimal. I plan on keeping the 30 spline np208 as a spare, as it is a direct bolt on when it is 700r4 32 spline time
Cons:
- In a nutshell, I have basically talked myself into doing something stupid. There are better and cheaper drivetrain options then the 700r4. If I could financially start my build over, I would have kept the 3.08 gears with the th400 and mated a np205/np203 doubler. In my opinion, if anyone wanted to do the 700r4 swap, I think 3.73 gears or lower with the M1009 is the absolute minimum one must have in their axles to best utilize the extra 4th gear. If not, one would find their 700r4 constantly jumping from 4th-3rd which causes excessive abnormal wear and tare on the clutches.
- Cost of this swap is a lot… You could have 3 TH400’s built with the cost of a 700r4 swap.
- Early model 700r4’s are prone to over heating. Remedy is to run an external transmission cooler.
- 27 spline input shaft breaks easily. Remedy is to upgrade to a 30 spline.
- The governor tends to stick as the fluid gets dirty. Remedy is to change fluid and filter every 30,000 miles or less.
- As time goes by, the Tv cable stretches and causes premature 700r4 failure. This can be avoided by checking adjustment every other oil change.
- The 700r4 weighs more at about 155 pounds empty vs the Th400’s 135 pounds.
- Over time, the accelerator pedal tends to bend which makes the TV cable out of adjustment causing excessive ware on the clutches. Remedy is to check adjustment every other oil change and bend the pedal back.
Am I missing anything?
So now you know all the pros and cons…
Let’s giterdun!
Parts List:
- Freshly rebuilt 27 spline 700r4 (Pic1)
- Freshly rebuilt 27 spline Np208 (Pic2)
- New or rebuilt 1400 stall Torque Converter with 6x10.75” bolt pattern. (Pic3) The 700r4 3 bolt torque converter will work too.
- Flex plate with 6x10.75 bolt pattern (Gm 1407715) (Pic4)
- Green head TV cable (Aka Kick down cable (Gm 25515599) (Pic5) The green head tv cable is vehicle specific for the 6.2-6.5/700r4. Gm does not make the Green head TV cables anymore and good luck finding one! But almost any Tv cable for the 700r4 will work with the proper adjustments.
- TV cable bracket (Pic6)
- TV cable rod (Pic7)
- 27 spline rear driveshaft/transfer case yolk (Pic)
- Th400 crossover transmission crossover brace (Pic9)
- Long 700r4 trans to t-case adapter. (Gm 14038663)(Pic10)
Parts list continued…
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