Simp's Cat 7155 Swap into a M923A1

simp5782

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Ok well today I yanked the starter back off. We have 1.75" from the flywheel face to the face of the bellhousing. Not including the stock spacer that is there. You can see the teeth marks on the starter. Little close to 2 inches with the spacer from face to the end of the bendix to yeah it was still locked in the teeth while running.

Clint is sending me a 1/2" spacer. Should have it on tomorrow. The stock spacer is barely 1/16" thick. so this should alleviate the problem.
 

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simp5782

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Alright sports fans I did a test drive today on the way home from the exhaust shop. I will be honest and just like everyone else when they first dealt with the transmission. I hate it. It is going to take some getting used to. I think mine is a throttle pedal problem it is not releasing all the way off so I will deal with that tomorrow. Raising the cab can cause a return issue. Tried dual springs and it is still doing it so I am going to have to remove the whole bracket and drill the hole for the throttle rod a little higher up on that plate. Should hopefully help.

Went with 5inch exhaust and a magnaflow muffler. so in case I ever decide to go big cam the exhaust is already in place. I am going to have to move the AC condenser towards the drivers side some to get it away from the exhaust. I may put the cage back on it to the inside Not sure yet. Was a nice little bend and down around the bellhousing to deal with.

As far as driving. Yeah your first time sucks. Especially with no bed it was pretty bumpy with the wrecker springs. I started in 8th. Has that slight bog on take off but spins up quick. shifting to 10 doesn't drop the rpms much. I have a whine in 11th thru 13th but once I get to 14th its gone. and yes when I hit 14th she takes off quick on picking up speed. I mean very quick I was quite impressed on the top end. I never got to 15 or 16 just city driving at traffic time. I will try to get a video tomorrow.


But she is mostly done. I will say this as a wise word of wisdom. It sucks to be the first person to do something. It really does. It took me about 5 weeks of some all day and some days of only a few hours. No help at all other than a roommate running the forklift to put the transmission in. Everything else other than the exhaust was done by me. The little crap is what irritates you the most. It is absolutely retarded how much little stuff takes up a lot of time. My advice. Don't be the first to do something different unless you just like pulling your hair out, cussing at yourself, and getting stir crazy. And yes I will say that I am the dumb retarded son of a gun that decided to do all the work in August.
 

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simp5782

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Looking real good! Now you need a Jake brake to slow that girl down!
Will worry about that if I go to a big cam. I actually dont have much room other than the stack to put it! The wedge brakes on these trucks are pretty strong when they are in good working order. Thanks for the pics on the shifter mod. I think itll be helpful. Empty anyway. I have a 600mile round trip drive on Thursday to get my trailer and stuff. Be a nice little test drive. She puts right along at 70 though with me barely on the throttle.
 

simp5782

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How come speedometer is not working.
Cat uses a different speedo cable than the 939 trucks. I moved the transfer case back 8 1/2" so the stock cable doesn't reach. Plus I know my speed off the sound of the engine and road feel. I run a gps on road trips.
 

Swamp Donkey

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I moved the transfer case back 8 1/2" so the stock cable doesn't reach.
Really? Mine has about 2' of slack in it. I had to replace it because the slack came loose where it was secured. The driveshaft had rubbed a hole in the sheath.
 

Castle Bravo

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That is really cool! I wish I had thought of something cool like this when the 7155 rebuilds were cheap and plentiful.

My 916 doesn't have a 7155 and I've never driven a truck with one, so its cool to be able to narrow down that particular whine that I hear in other 916/920 videos as being the transmission.
 

Csm Davis

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Will worry about that if I go to a big cam. I actually dont have much room other than the stack to put it! The wedge brakes on these trucks are pretty strong when they are in good working order. Thanks for the pics on the shifter mod. I think itll be helpful. Empty anyway. I have a 600mile round trip drive on Thursday to get my trailer and stuff. Be a nice little test drive. She puts right along at 70 though with me barely on the throttle.
Real Jake goes on the top of the heads not an exhaust brake like your wimpy ford has.

Sent from my SM-G930V using Tapatalk
 

MAdams

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I can't tell from the video, but it looks like the rpm drop between gears is 4-500 rpm. I would have though the gears would be a lot closer in ratio.
 

74M35A2

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Honk if you have Jakes (beep beep, but mine are still in the toolbox!).

13 speed manual I am doing will drop 500rpm each gear for 2-5 (1st is low), then 250rpm per each 6-13. Will sound like an Indy car!

IMG_4186.jpg

I love talking about me on Simp's threads...
 
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simp5782

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I can't tell from the video, but it looks like the rpm drop between gears is 4-500 rpm. I would have though the gears would be a lot closer in ratio.
It is about 550 when I jump 2 gears which is what I am doing on the interstate takeoff. 7,9,11,13,14,15,16.

If I go to 2200 and shift one it is right back to 1850/1900 give or take
 

simp5782

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Went on a 600 mile round trip test drive to get my trailer. Ended up with a starter issue and swapped it out. Also ended up with a Shifter failure. backed up to hook up to my trailer. got out to look at my positioning got back in and shifted to R and the poppets would just continuously reset. So I had to come back to Memphis via car and get my spare shifter. along the way I stopped and bought 5 ones in the crates from a guy for $500. So I guess ill have spares. Got back home a little bit ago. I was 17 minutes faster from Nashville to Memphis unloaded than normal. I drove from Cookeville with my trailer and probably 4000lbs of cargo and crap and I never dropped below 14th gear on pulling a few long hills. I did surprisingly well.
 

simp5782

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What cruising speed did you settle into and what rpm is that at?
67/68 at around 1950 it likes to sit there and is smooth with the trailer

Empty it was liking 70 right on at 2k or a lil over.

Sent from my SM-G935P using Tapatalk
 
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