CUCV Flexplate Replacement: Step-by-Step Guide

[Zeb]

I recently replaced the flexplate on my '85 M1008, following the instructions posted by @acmunro in a 2009 SS thread. His instructions were enough, and probably more than enough for most SS users to follow, but to be honest as a novice I could have used a little more detail. So using his instructions as scaffolding, I typed up a more detailed Step-By-Step guide. For most of yall the extra details are probably painfully obvious points that don't warrant mentioning, but I'm hoping that if someone like me gives this a shot in the future they will find this helpful (and hopefully get it done quicker and with less missteps than I did... those unfortunate details can be found in my other thread).

Instructions for Replacing CUCV Flexplate (without removing transmission)

1. Disconnect the battery cables, engage parking brake, chock tires
2. Disconnect the transmission vacuum hardline from transmission modulator valve
   • not mentioned in @acmunro's instructions, but I found this necessary to create enough space to disconnect the transmission cooler lines, and also to prevent potentially stretching this line when sliding the transmission back
3. Disconnect the transmission cooler lines
   • also not mentioned in @acmunro's instructions, but I found this necessary to more easily remove the torque converter cover bolts and also to prevent stretching these lines when sliding the transmission back
4. Remove the four lower bolts that hold the bell housing to the engine block
5. Replace them with four 4" 3/8 - 16 SAE bolts
   • this allows you to slide the transmission back away from the motor, giving you enough space to remove the flexplate from the crankshaft, while keeping everything lined up so that you can easily slide it all back together
6. Remove the starter
7. Remove the torque converter cover
8. Remove the six bolts that secure the torque converter to the flexplate
   • the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
     • I used a wrench lodged in one of the large holes near the center of the plate
9. Remove the remaining bell housing bolts
   • there are 2 more bolts to remove, at the top of the bellhousing, and they are a b***h to get to
     • Without extensions, I found it easier to pop the hood and remove these bolts from above
     • Per @dependable, the easiest way to get to these bolts is by reaching over the transmission from 2.5’-3’ back using several extensions
10. Disconnect the transmission shift linkage
11. Disconnect the transfer case shift linkage
12. Disconnect transfer case wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into the top of the transfer case
13. Disconnect the kickdown switch wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into driver side of the transmission
14. Disconnect the speedometer cable
    • to prevent overstretching when sliding the assembly back
    • this can be found plugging into the rear passenger side of the transmission
15. Disconnect the front drive shaft at the transfer case
    • like the flexplate, this will try to spin as you wrench, so wedge something in the yoke to keep it from spinning
      • I once again used a wrench here, shoved into the yoke to prevent spinning
16. Disconnect the rear drive shaft
    • can be done at the transfer case if you don't mind fluid draining out, or as I did you can remove it at the rear axle by disconnecting the Ujoint from the pinion yoke
      • if you do it the second way be careful not to allow the Ujoint end caps to fall off (they are not secured by anything other than pinion yoke tabs, so once disconnected these can slide off easily and spill bearings if you aren't careful)
17. Put a wheeled floor jack under the cross member
18. Remove the four cross member bolts
    • all of the weight will be on the jack and 4 longer replacement bellhousing bolts at this point
19. Slide transmission assembly back
    • the weight of which is now on the floor jack via the cross member
    • the four longer bellhousing bolts that you installed in step 4 will allow you to slide the assembly far enough back to reach up and remove the flexplate to crankshaft bolts, while keeping everything lined up so that you can more easily slide it all back together
20. Remove the 6 bolts that secure the flexplate to the crankshaft
    • once again the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
      • I again used a wrench lodged in one of the large holes near the center of the plate
21. Remove old flexplate
22. Mount new flexplate
    • fit is tight, and thus it can be difficult to slide the new plate on to the crankshaft... so be sure to tighten each bolt just a little bit at a time in an alternating pattern to prevent warping the plate as you cinch it down
23. Reassemble
    • Follow the preceding instructions in reverse order
    • Tips for sliding assembly back into place
      • make sure the torque converter is fully seated into the transmission front pump before mating bell housing to engine block... if you tighten everything down before doing so you will break the pump rotor
        • you shouldn't be able to fit your fingers behind the torque converter. If you can, it's not fully seated. Before reassembly push in on the converter while spinning it, and you should feel it bottom out
      • be sure that nothing has slipped in between the bellhousing and engine block that might prevent a snug fit
        • common culprits per @Squibbly:
          • fill tube bracket that mounts to the top right bolt
          • kickdown switch wire holder bracket that mounts to the middle left bolt
      • use the dowel fittings in between the bottom two bolts on each side of the bellhousing to help line everything up
        • they match to holes on the engine block, and you can use these to visually check that everything is aligned left to right

• Tips from SS Users
  • From @cucvrus

    • the hardest part I encountered over the years was the stripped and twisted cooler lines. Some I could not get out because they were stripped and had rubber hoses installed. I have since changed my method. If I encounter stripped hacked up cooler lines that are spliced, I add hydraulic rubber lines and run them up over top of the transmission. That is a bit costly, but it saved me from getting them caught when off road and snow plowing. The next thing that can be a bear is the fill tube. Replace the shot glass shaped grommet that goes in the transmission and try, and wire tie the fill tube up in the general area where it is supposed to be. It can be a challenge and I have encountered more than 1 that was never put back in place with the tab bolted to the bell housing.

• Parts/Supply/Tool List:
  
  • New flexplate (I went with a Pioneer FRA-142 from Autozone)
  • New starter ( I used a Rebuilt direct drive starter from Hillbilly Wizard)
  • Flexplate Bolt kit
  • Blue Threadlocker
  • Four 4" 3/8 - 16 SAE bolts
  • Metric socket wrench set
  • Short handled wrench set
  • Short handled needle nose pliers
  • Wheeled floor jack
  • Wrench extensions (not required, but helpful)

Hopefully this will help somebody in the future. In case you're reading this and have doubts that you can tackle this job.... if an idiot like me can do this with only larger-than-ideal hand tools on a sloped-gravel driveway, ANYBODY can do it. Just go slow, ask questions, and try to have everything you need beforehand.

*If I am missing anything off the part/tool list, or if any parts in the instructions are misidentified or just wrong, PLEASE LET ME KNOW AND I WILL GLADLY EDIT

 

[INFChief]

I recently replaced the flexplate on my '85 M1008, following the instructions posted by @acmunro in a 2009 SS thread. His instructions were enough, and probably more than enough for most SS users to follow, but to be honest as a novice I could have used a little more detail. So using his instructions as scaffolding, I typed up a more detailed Step-By-Step guide. For most of yall the extra details are probably painfully obvious points that don't warrant mentioning, but I'm hoping that if someone like me gives this a shot in the future they will find this helpful (and hopefully get it done quicker and with less missteps than I did... those details can be found in my other thread).
*In full disclosure, these instructions were copy & pasted the other thread referenced above... just didn't want these buried so deep in that conversation that nobody could ever find them

Instructions for Replacing CUCV Flexplate (without removing transmission)

1. Disconnect the transmission vacuum hardline from transmission modulator valve
   • not mentioned in @acmunro's instructions, but I found this necessary to create enough space to disconnect the transmission cooler lines, and also to prevent potentially stretching this line when sliding the transmission back
2. Disconnect the transmission cooler lines
   • also not mentioned in @acmunro's instructions, but I found this necessary to more easily remove the torque converter cover bolts and also to prevent stretching these lines when sliding the transmission back
3. Remove the four lower bolts that hold the bell housing to the engine block
4. Replace them with four 4" 3/8 - 16 SAE bolts
   • this allows you to slide the transmission back away from the motor, giving you enough space to remove the flexplate from the crankshaft, while keeping everything lined up so that you can easily slide it all back together
5. Remove the starter
6. Remove the torque converter cover
7. Remove the six bolts that secure the torque converter to the flexplate
   • the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
     • I used a wrench lodged in one of the large holes near the center of the plate
8. Remove the remaining bell housing bolts
   • there are 2 more bolts to remove, at the top of the bellhousing, and they are a b***h to get to
     • I found it easier to pop the hood and remove these bolts from above
9. Disconnect the transmission shift linkage
10. Disconnect the transfer case shift linkage
11. Disconnect transfer case wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into the top of the transfer case
12. Disconnect the kickdown switch wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into driver side of the transmission
13. Disconnect the speedometer cable
    • to prevent overstretching the when sliding the assembly back
    • this can be found plugging into the rear passenger side of the transmission
14. Disconnect the front drive shaft at the transfer case
    • like the flexplate, this will try to spin as you wrench, so wedge something in the yoke to keep it from spinning
      • I once again used a wrench here, shoved into the yoke to prevent spinning
15. Disconnect the rear drive shaft
    • can be done at the transfer case if you don't mind fluid draining out, or as I did you can remove it at the rear axle by disconnecting the Ujoint from the pinion yoke
      • if you do it the second way be careful not to allow the Ujoint end caps to fall off (they are not secured by anything other than pinion yoke tabs, so once disconnected these can slide off easily and spill bearings if you aren't careful)
16. Put a wheeled floor jack under the cross member
17. Remove the four cross member bolts
    • all of the weight will be on the jack and 4 longer replacement bellhousing bolts at this point
18. Slide transmission assembly back
    • the weight of which is now on the floor jack via the cross member
    • the four longer bellhousing bolts that you installed in step 4 will allow you to slide the assembly far enough back to reach up and remove the flexplate to crankshaft bolts, while keeping everything lined up so that you can more easily slide it all back together
19. Remove the 6 bolts that secure the flexplate to the crankshaft
    • once again the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
      • I again used a wrench lodged in one of the large holes near the center of the plate
20. Remove old flexplate, mount new flexplate
    • fit is tight, and thus it can be difficult to slide the new plate on to the crankshaft... so be sure to tighten each bolt just a little bit at a time in an alternating pattern to prevent warping the plate as you cinch it down
21. Reassemble
    • Follow the preceding instructions in reverse order
    • Tips for sliding assembly back into place
      • make sure the torque converter is fully seated into the transmission front pump before mating bell housing to engine block... if you tighten everything down before doing so you will break the pump rotor
        • you shouldn't be able to fit your fingers behind the torque converter. If you can, it's not fully seated. Before reassembly push in on the converter while spinning it, and you should feel it bottom out
      • be sure that nothing has slipped in between the bellhousing and engine block that might prevent a snug fit
        • common culprits per @Squibbly:
          • fill tube bracket that mounts to the top right bolt
          • kickdown switch wire holder bracket that mounts to the middle left bolt
      • use the dowel fittings in between the bottom two bolts on each side of the bellhousing to help line everything up
        • they match to holes on the engine block, and you can use these to visually check that everything is aligned left to right

• Parts/Supply/Tool List:
  • New Flexplate
  • New starter ( I used a Rebuilt direct drive starter from Hillbilly Wizard)
  • Flexplate Bolt kit
  • Blue Threadlocker
  • Four 4" 3/8 - 16 SAE bolts
  • Metric socket wrench set
  • Short handled wrench set
  • Short handled needle nose pliers
  • Wheeled floor jack
    

Hopefully this will help somebody in the future. In case you're reading this and have doubts that you can tackle this job.... if an idiot like me can do this with only larger-than-ideal hand tools on a sloped-gravel driveway, ANYBODY can do it. Just go slow, ask questions, and try to have everything you need beforehand.

*If I am missing anything off the part/tool list, or if any parts in the instructions are misidentified or just wrong, PLEASE LET ME KNOW AND I WILL GLADLY EDIT

Very thorough! I would add 1 thing up front. Disconnect the battery cables.

 

[Zeb]

Very thorough! I would add 1 thing up front. Disconnect the battery cables.

I thought about starting with "disconnect battery cables, put parking brake on, chock tires", but thought that might be too detailed/painfully obvious... but then again I wrote this with the idea that an extreme-novice could follow it, so it makes sense to include that. Plus I'm sure some of the other steps I included were painfully obvious to other CUCV owners, so I'll add it in. Thanks!

 

[dependable]

Nice write up.

You noted the top bell housing bolts are hard to get to, so you accessed from top, these can be challenging. I've found the easiest way to get at them is to use several extensions, two and a half feet or three feet worth, and get at bolts from further back reaching over transmission. I usually use 3/8 inch drive ones as they fit up there better, but 1/2 inch will work. A well placed wobbly extension two can help, but not too many. Often times enough bend and flex in extensions will be achieved just by using several shorter ones.

 

[Zeb]

Nice write up.

You noted the top bell housing bolts are hard to get to, so you accessed from top, these can be challenging. I've found the easiest way to get at them is to use several extensions, two and a half feet or three feet worth, and get at bolts from further back reaching over transmission. I usually use 3/8 inch drive ones as they fit up there better, but 1/2 inch will work. A well placed wobbly extension two can help, but not too many. Often times enough bend and flex in extensions will be achieved just by using several shorter ones.

Thanks for mentioning that. I added it to the subnote on that step. I definitely need some extensions! Would probably make working on the truck a lot easier

 

[cucvrus]

I have a 48" 1/2" female and 3/8" male extension. I have removed and replaced several hundred transmissions. Most of my experience is removal and salvage. Just because I have a good friend with a salvage yard and help out whenever I can. Not so much this past year but every weekend in the by gone years. Man, we scrapped a lot of good stuff over the years unknowingly. I myself sent many CUCV's to the scrap pile. I never knew. They were just trucks to me, and they plowed snow. Merry Christmas.

 

[Squibbly]

Nice write up.

You noted the top bell housing bolts are hard to get to, so you accessed from top, these can be challenging. I've found the easiest way to get at them is to use several extensions, two and a half feet or three feet worth, and get at bolts from further back reaching over transmission. I usually use 3/8 inch drive ones as they fit up there better, but 1/2 inch will work. A well placed wobbly extension two can help, but not too many. Often times enough bend and flex in extensions will be achieved just by using several shorter ones.

I ended up taking off my Transmission tunnel cover, because someone torqued the top bolts too tight and the angle to get to them with that much torque was difficult.

After I took of that cover, not only were the bolts so much easier to get to and that top fill tube bracket, but the 4x4 indicator light switch was. I was also able to clean up the top of the transmission.

If I had to do the job again. I would absolutely take that cover off again.

Just make sure you cover the hole when you aren’t using it. Apparently finches like flying up into vehicles with openings at the bottom.

On 4 separate occasions I’d go inside for a few minutes and come out and they’d be flying around inside the truck.


Sent from my iPhone using Tapatalk

 

[AP Labs]

I recently replaced the flexplate on my '85 M1008, following the instructions posted by @acmunro in a 2009 SS thread. His instructions were enough, and probably more than enough for most SS users to follow, but to be honest as a novice I could have used a little more detail. So using his instructions as scaffolding, I typed up a more detailed Step-By-Step guide. For most of yall the extra details are probably painfully obvious points that don't warrant mentioning, but I'm hoping that if someone like me gives this a shot in the future they will find this helpful (and hopefully get it done quicker and with less missteps than I did... those unfortunate details can be found in my other thread).

Instructions for Replacing CUCV Flexplate (without removing transmission)

1. Disconnect the battery cables, engage parking brake, chock tires
2. Disconnect the transmission vacuum hardline from transmission modulator valve
   • not mentioned in @acmunro's instructions, but I found this necessary to create enough space to disconnect the transmission cooler lines, and also to prevent potentially stretching this line when sliding the transmission back
3. Disconnect the transmission cooler lines
   • also not mentioned in @acmunro's instructions, but I found this necessary to more easily remove the torque converter cover bolts and also to prevent stretching these lines when sliding the transmission back
4. Remove the four lower bolts that hold the bell housing to the engine block
5. Replace them with four 4" 3/8 - 16 SAE bolts
   • this allows you to slide the transmission back away from the motor, giving you enough space to remove the flexplate from the crankshaft, while keeping everything lined up so that you can easily slide it all back together
6. Remove the starter
7. Remove the torque converter cover
8. Remove the six bolts that secure the torque converter to the flexplate
   • the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
     • I used a wrench lodged in one of the large holes near the center of the plate
9. Remove the remaining bell housing bolts
   • there are 2 more bolts to remove, at the top of the bellhousing, and they are a b***h to get to
     • Without extensions, I found it easier to pop the hood and remove these bolts from above
     • Per @dependable, the easiest way to get to these bolts is by reaching over the transmission from 2.5’-3’ back using several extensions
10. Disconnect the transmission shift linkage
11. Disconnect the transfer case shift linkage
12. Disconnect transfer case wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into the top of the transfer case
13. Disconnect the kickdown switch wiring
    • to prevent overstretching when you slide the assembly back
    • this wiring can be found plugging into driver side of the transmission
14. Disconnect the speedometer cable
    • to prevent overstretching when sliding the assembly back
    • this can be found plugging into the rear passenger side of the transmission
15. Disconnect the front drive shaft at the transfer case
    • like the flexplate, this will try to spin as you wrench, so wedge something in the yoke to keep it from spinning
      • I once again used a wrench here, shoved into the yoke to prevent spinning
16. Disconnect the rear drive shaft
    • can be done at the transfer case if you don't mind fluid draining out, or as I did you can remove it at the rear axle by disconnecting the Ujoint from the pinion yoke
      • if you do it the second way be careful not to allow the Ujoint end caps to fall off (they are not secured by anything other than pinion yoke tabs, so once disconnected these can slide off easily and spill bearings if you aren't careful)
17. Put a wheeled floor jack under the cross member
18. Remove the four cross member bolts
    • all of the weight will be on the jack and 4 longer replacement bellhousing bolts at this point
19. Slide transmission assembly back
    • the weight of which is now on the floor jack via the cross member
    • the four longer bellhousing bolts that you installed in step 4 will allow you to slide the assembly far enough back to reach up and remove the flexplate to crankshaft bolts, while keeping everything lined up so that you can more easily slide it all back together
20. Remove the 6 bolts that secure the flexplate to the crankshaft
    • once again the flexplate will want to spin as you try to loosen these bolts, so find a way to wedge and prevent it from spinning
      • I again used a wrench lodged in one of the large holes near the center of the plate
21. Remove old flexplate
22. Mount new flexplate
    • fit is tight, and thus it can be difficult to slide the new plate on to the crankshaft... so be sure to tighten each bolt just a little bit at a time in an alternating pattern to prevent warping the plate as you cinch it down
23. Reassemble
    • Follow the preceding instructions in reverse order
    • Tips for sliding assembly back into place
      • make sure the torque converter is fully seated into the transmission front pump before mating bell housing to engine block... if you tighten everything down before doing so you will break the pump rotor
        • you shouldn't be able to fit your fingers behind the torque converter. If you can, it's not fully seated. Before reassembly push in on the converter while spinning it, and you should feel it bottom out
      • be sure that nothing has slipped in between the bellhousing and engine block that might prevent a snug fit
        • common culprits per @Squibbly:
          • fill tube bracket that mounts to the top right bolt
          • kickdown switch wire holder bracket that mounts to the middle left bolt
      • use the dowel fittings in between the bottom two bolts on each side of the bellhousing to help line everything up
        • they match to holes on the engine block, and you can use these to visually check that everything is aligned left to right

• Tips from SS Users
  • From @cucvrus

• Parts/Supply/Tool List:
  
  • New flexplate (I went with a Pioneer FRA-142 from Autozone)
  • New starter ( I used a Rebuilt direct drive starter from Hillbilly Wizard)
  • Flexplate Bolt kit
  • Blue Threadlocker
  • Four 4" 3/8 - 16 SAE bolts
  • Metric socket wrench set
  • Short handled wrench set
  • Short handled needle nose pliers
  • Wheeled floor jack
  • Wrench extensions (not required, but helpful)

Hopefully this will help somebody in the future. In case you're reading this and have doubts that you can tackle this job.... if an idiot like me can do this with only larger-than-ideal hand tools on a sloped-gravel driveway, ANYBODY can do it. Just go slow, ask questions, and try to have everything you need beforehand.

*If I am missing anything off the part/tool list, or if any parts in the instructions are misidentified or just wrong, PLEASE LET ME KNOW AND I WILL GLADLY EDIT

Wow! You must have a career as a technical writer! I have two trucks that I have to replace flexplates and your script gives me all the confidence I need! Thanks from a new Steel Soldiers member.