CAT 3116 AT545 to MT643/653 - Page 2

DtotheAmbrose · 03-26-2020, 05:26 PM

I got the passenger fuel tank re-installed and filled back up and got a chance to drive the truck.

1st is a little long and it holds until 15mph until it shifts.
2nd felt pretty good and under light load and it shifts into 3rd at ~ 22mph.
3rd is one hell of a drop in RPM when you hit a lockup gear, wow. The RPM drop right at the happy torque place for the engine. The frequency from the rpm/load is actually causing the roof on the toter to vibrate like a cymbal. The truck moves though, 40 mph comes up pretty quick.
4th feels great. The truck seems pretty happy at 55-60mph. I get into the turbo a little bit holding 65mph but it is pretty light.

I have not hooked up the 40ft trailer yet and gone for a drive. Based on the way the truck drives I need some more low end oomph for 3rd and 4th. The upgraded turbo and fun screw adjustment will happen first before I try that. I am hoping to get to that this weekend.

Booyah45828 · 03-27-2020, 08:39 AM

Do your upgrades first.

Then we can adjust it so it works better. How you do that is by noting the shift rpm for each gear at full throttle and then you can adjust the individual points with the adjusters on the valve body. Usually, they're adjusted correctly from the factory or shop rebuilder, and they never have to be touched.

But before you do any of that, you make sure the modulator is working correctly and the governor is correct for the application/usage.

cadillackid · 03-27-2020, 09:22 AM

the lockup engage in 3rd is definitely a big drop in RPM...going 3-4 is also a steep gear

cadillackid · 03-27-2020, 09:26 AM

to test your theoretical shift points.. ie if running gears out longer will help you, then drive the T-handle.. you cant really control lockup (I think its a spring and piston in the valve body).. but you can run 3rd out higher then manually go to 4.. 3-4 like I mention is steep.. on my DTA360, peak HP is at 2300 RPM.. the auto shift point ofthe 643 for 3-4 with full-out modulator is at 2500 RPM which throws me into a point where I lose turbo spool.. if I run 3rd out to redline 2800 RPM, the shift puts me high enough where the turbo stays up and I continue good acceleration. I dont know the peak RPMs for TQ and HP on the CAT but I think they are similar

DtotheAmbrose · 03-27-2020, 05:13 PM

This trans looks to have never been touched and didn't look cleaned which I was happy about. The MT643 had an electronic modulator which I swapped out for the mechanical version from the truck and it seems to be working fine.

I have seen a few different numbers for peak HP but the consensus is 2400 rpm based on the HP mine has. I haven't gone out a ran it out in the gears at WOT yet. I am out in the country a bit so I will give that a shot. If I am at WOT the shift point for 3rd moves out to ~26mph which helps on the drop.

The new turbo I have is a Borg Warner SX200 177257 which is a non-wastegate turbos to start with which is perfect for the truck. It is a T4 flange and uses the same size exhaust v-band out let to make it a bolt on. The compressor cover also is the same size for inlet and outlet at the stock cat turbo. The only hang up on installation will be the oil feed. The stock cat is a 2 bolt flange and the SX200s are a thread in fitting. I am going to have the local hydraulic place make me a flex line for the install.

Stock 3116 Cat Turbo is a 55.98 inducer, 7+7 blade on the compressor and a 69.6 inducer and 60.6 exducer 10 blade turbine with what looks to be a .83 AR exhaust housing.

The BW 177257 is a 51mm extended tip inducer, 7+7 blade on the compressor and a 70 inducer 61 exducer 10 blade turbine with a .83 AR exhaust housing. Link for the specific BW pdf on the turbo

My logic on this is to give up a little bit of the maximum flow in exchange for a better response on spool up to drop the peak torque a few hundred RPM. We shall see how well I did on this soon enough.

Booyah45828 · 03-27-2020, 08:07 PM

Quote:

Originally Posted by DtotheAmbrose

The BW 177257 is a 51mm extended tip inducer, 7+7 blade on the compressor and a 70 inducer 61 exducer 10 blade turbine with a .83 AR exhaust housing. Link for the specific BW pdf on the turbo

My logic on this is to give up a little bit of the maximum flow in exchange for a better response on spool up to drop the peak torque a few hundred RPM. We shall see how well I did on this soon enough.

That turbo looks like a good choice for a stock replacement. The airwerks line is a pretty modern design. It's still journal bearing and oil cooled.

I think you'll be disappointed though if you're looking to drop the peak torque. That's more of a fuel change then a turbo change. I'd definitely look up adjusting the fuel screw on that engine. Doing that with your new turbo and I'd say you'll be pleased.

DtotheAmbrose · 05-09-2020, 07:53 PM

Alright I sort of fell off planet a bit with the covid crap, work exploded and I have been non stop for the past 6 weeks.

I will get an more detailed update posted shortly but the short version.

#1 the data I had from my stock turbo was wrong so I picked up a different turbo, a S200SXE 3.5 inch inlet variant (bigger) and got it installed. With all the parts on it it looks completely stock. The new turbo is also is less audible than the original, you can hear it but you have to be listening for it to notice it aka it doesn't appear to be working very hard.

#2 With the new turbo and the fuel screw out 2 turns the truck isn't too bad driving around town. I will try it with the trailer hooked up empty next week, I need to swap out the fuel filters as the 50 gallon tanks I installed last year were used and had some sediment floating around in them after I filled them up.

dimoimo · 07-22-2020, 08:26 AM

Can you give a run down of the additional hardware you needed aside from the transmission itself for the swap?

I see:

Transmission
Flex Plate
Flywheel
Bell housing hardware
Parking Brake
Electrical connectors (When you say directly swapped from the at545, do you mean plug and play, or did you have to rewire the plugs?)
Shift Selector (Were you able to swap it over directly?)
Dipstick tube (Did you find a solution for this?)

I appreciate all the work you've put into documenting this. Hoping to do the same swap on my 3126 based GMC for more towing capacity.

DtotheAmbrose · 07-22-2020, 09:36 AM

Quote:

Originally Posted by dimoimo

Can you give a run down of the additional hardware you needed aside from the transmission itself for the swap?

I see:

Transmission
Flex Plate
Flywheel
Bell housing hardware
Parking Brake
Electrical connectors (When you say directly swapped from the at545, do you mean plug and play, or did you have to rewire the plugs?)
Shift Selector (Were you able to swap it over directly?)
Dipstick tube (Did you find a solution for this?)

I appreciate all the work you've put into documenting this. Hoping to do the same swap on my 3126 based GMC for more towing capacity.

I picked up the transmission (including torque convertor), flex plate, spacer, and hardware from Holst out of Idaho. I told them what I was doing and they sent everything, $1300 shipped if I remember correctly.

The bellhouse hardware was re-used from the AT545.

Parking brake took some digging but I finally found one at a wrecker outside of phoenix AZ. They are out there just not common.

Sensors: Plug and play. no re-wiring. I did re-route one to get a little slack in the wiring.

Shift selector I had trim up the MT543 unit as the one that came with the trans was from a cummins so the routing was different. Basically it moved the attachment point from the back of the lever to the front of the lever.

I was able to work out a path for the dipstick/tube which came with the transmission. It sits a little further under the cab but when you pull the wheel liner it is easy to access and fill.

*** One thing I forgot to mention during this swap, on the GMC trucks like mine the exhaust has a bracket which bolts to the bellhouse. With the bellhouse being larger and bolt spacing a little larger I had to re-work the bracket to hold the exhaust. Make sure you do this, the exhaust pipe leverage is ~4 feet back to the next hangar (at least on my truck) and I didn't want to crack an exhaust manifold from the load)

It is wildly different towing with this trans over the AT545. Max load I have pulled so far was ~45k making the total weight of everything ~67k. Pulls like a champ.

I left the large external transcooler in place I had when I was trying to keep the AT545 from killing itself from heat. It has a thermoswitched fan (set to 185f). I have never had the fan switch on after the transmission swap. I was a bit worried it wasn't working so I did a test with a heat gun and it worked.

Topkickindiana · 07-29-2020, 08:57 PM

Hello again, so I bought a good mt643 from lkq , it's doing the same thing again IDK if I am installing it wrong or something... I have no pressure in it again , there is no oil in cooling lines and the yolk spins super slow I'm not sure what the deal is maybe it needs to be bleeded from the top to the pump? I cant find any forms online with the same issue as mine

Booyah45828 · 07-29-2020, 09:02 PM

Quote:

Originally Posted by Topkickindiana

Hello again, so I bought a good mt643 from lkq , it's doing the same thing again IDK if I am installing it wrong or something... I have no pressure in it again , there is no oil in cooling lines and the yolk spins super slow I'm not sure what the deal is maybe it needs to be bleeded from the top to the pump? I cant find any forms online with the same issue as mine

It doesn't need bled.

Did you verify the converter was fully engaged into the transmission before you installed it? If you have a pan full of fluid, a properly installed pickup screen, a good oil pump, and a properly installed torque converter, then you'll have fluid flowing.

If you don't, look into which of the above you're missing and fix it.

Topkickindiana · 07-29-2020, 09:48 PM

I had the converter installed to the flywheel first then I mated the transmission , what is the proper way to install it?

Booyah45828 · 07-29-2020, 10:08 PM

Not that way. You have to install it into the trans first to line up the splines and pump drive. Doing the way you did it, it's about a guarantee that it's not right and you likely damaged it in the process.

Your next step is to remove and disassemble the trans. Inspect all the pieces for damage and then reassemble and install it the correct way.

Topkickindiana · 07-29-2020, 10:47 PM

Thank u very much lesson learned the hard way but I'm sure it's still fine I will try to install it properly tomorrow and will keep u updated on how it turns out ��

Booyah45828 · 07-30-2020, 07:17 AM

Quote:

Originally Posted by Topkickindiana

I'm sure it's still fine

I've never seen one that was fully installed wrong, started up, and then turned out fine.

I'm not a big fan on removing and installing transmissions. So if it were me, I'd make sure everything was good before I pushed it back in for the 3rd time. But, you can try it if you want, at this point you're likely only out the time and labor.

cadillackid · 07-30-2020, 07:18 AM

this sounds exactly like booyah mentioned.. if you look at your old transmission and torque converter you can see on the shaft of the converter 2 little notches... those notches when inserted into the transmission engage 2 'ears' which are the main fluid pump.. when installing the converter to the transmission you rotate the converter are you put it on the trans input shaft and you will feel it engage the input shaft splines and then finally those pump ears.. if you install the converter on the flywheel first the converter cant be rotated to properly catch those ears so you end up smashing them and destroying the front pump in the transmission. if the pump operates at all when you first start it you send metal shrapnel instantly through the transmission.. if you are lucky the pump never operated and you can simply replace the pump.. the transmission can be removed from the bus and the pump removed from the transmission and disassembled.. if the pump never operated it will not be full of fluid.. if its full of fluid you will need to rebuild the transmission otherwise you can take the front pump to a shop and have it rebuilt..

you need to inspect the torque converter itself to make sure the notches arent damaged .. if they are you'll need a new converter..

the good thing is unless things went really bad you likely will not have damaged the engine flywheel(flexplate)..

-Christopher

cadillackid · 07-30-2020, 07:29 AM

ive been doing transmissions and engines for a long time.. ive rarely seen this scenerio turn out with nbothing damaged.. if it were then the pump wouldve slipped itself into the converter notches and took off

these kinds of things are recoverable..

I remove and install them all the time.. the allisons are just big and heavy otherwise they are easier than doing car transmisisons since the engines support themselves

-Christopher

Topkickindiana · 08-06-2020, 08:35 PM

I guess I'm lucky! Mt643 working great and shifts good sure makes a big difference between at545!!

EastCoastCB · 08-06-2020, 08:40 PM

Quote:

Originally Posted by Topkickindiana

I guess I'm lucky! Mt643 working great and shifts good sure makes a big difference between at545!!

I sure wish I had a 643. Or a 2000 with that od.

RolesvilleMarina · 09-02-2020, 09:57 AM

Quote:

Originally Posted by cadillackid

this sounds exactly like booyah mentioned.. if you look at your old transmission and torque converter you can see on the shaft of the converter 2 little notches... those notches when inserted into the transmission engage 2 'ears' which are the main fluid pump.. when installing the converter to the transmission you rotate the converter are you put it on the trans input shaft and you will feel it engage the input shaft splines and then finally those pump ears.. if you install the converter on the flywheel first the converter cant be rotated to properly catch those ears so you end up smashing them and destroying the front pump in the transmission. if the pump operates at all when you first start it you send metal shrapnel instantly through the transmission.. if you are lucky the pump never operated and you can simply replace the pump.. the transmission can be removed from the bus and the pump removed from the transmission and disassembled.. if the pump never operated it will not be full of fluid.. if its full of fluid you will need to rebuild the transmission otherwise you can take the front pump to a shop and have it rebuilt..

you need to inspect the torque converter itself to make sure the notches arent damaged .. if they are you'll need a new converter..

the good thing is unless things went really bad you likely will not have damaged the engine flywheel(flexplate)..

-Christopher

reading this makes me cringe when I realize how close I came to doing some of these things... like panicking when the torque converter was just shy of snugging up, and you told me relax and just scootch it and it was supposed to be this way.

especially during my swap when I thought the flywheels needed replacing too and I basically would've grenaded both motors

You may also like: