1995 fzj80 5.3/4l60e/np203/splitcase swap

[Mr.Bryan]

Hey Guys,

I've been posting around here with different comments on my swap, but I figured I'd make it official and put down the info that I'm finding while going through this swap. I'm about halfway done at this point but here's what I got so far...



I decided to do the swap not for the 5.3 but for the gearing option of going to dual t-cases with the np203 and the split case. It gives me a 2:1 and 4:1 options which should be nice. The added benefit of the swap was more power, stronger trans and losing 400lbs up front.

No issues with pulling the motor.

I picked up my engine and trans from an LKQ junk yard near me in blue island. $1600+tax for an '03 Yukon XL 5.3 and 4l60e with about 94k mi. on it. Nice thing is it has a 6.mo warranty.

I ordered the np203 to split case adapter from Jerry at from Colorado off road and had it shipped to off road design. I ordered the np203 from off road design and they sent me a rebuilt 203 with the adapter installed which was nice and easy. The 203 was drilled and tapped to bolt right on to the 4l60e with no adapters.

I picked up a split case from Gumby (Thanks again!) and put those two together. They make a nice little pair behind the trans.

I cut off the old engine mounts ground everything flush and welded on a set of dirty dingo street rod adjustable mounts.

From warpdriv's thread I picked up a bunch of info. I ordered the block hugger hooker headers from summit racing and those worked out great. They tuck very nicely between the frame rails. I also picked up a 1999 camaro oil pan for clearance with the front axle. I also went with a wiring harness and other bits that needed to go along with that (TAC module, gas pedal for fly by wire system and 2 position brake switch) from Jon at PSI. Great guy by the way. He sent me all the bits I needed and programed the PCM so everything should be peachy keen.

Spent the earlier part of this weekend finishing up the cross member to support the trans. Thanks to 4rnr on that one. We used the existing cross member to start with and then used 2.5" 1/4 wall square tube to build a mount that bolted to bottom rear of the 4l60e. Should be strong as an ox. I'll throw up a few pictures soon.

At this point, I'm going to have to have the rear drive shaft lengthen and front shortened by a few inches. Who knew going to dual t-cases would be an overall shorter drive train...
It's close as far as clearance goes between the flange on the front axle and the oil pan, but it should be ok.

Projects for this week are to take care of the drive shafts, start getting some custom power steering lines made, and start working on the fuel system and get shifters ordered. I'm going to go with an art carr shifter and set up some custom linkages for the t-cases.

I've ordered a tt supra pump to drop in the tank and I'm thinking of running a corvette fuel filter near the engine instead of setting up a fuel pressure regulator as the filters are internally regulated. Not sure how that will adapt to the engine at this point as the 5.3 has a return and the return with the corvette filter is on the filter. Anyone know how I can make that work?

That's basically where I'm at. I'll post up some pictures in a bit. Gotta head out to dinner with the in-laws.

 

[warpdriv]

This is going to be badass!!! I did a 700R4/NP203/3sp case in my 40. You are going to LOVE stupid low! Just be light on the skinny pedal when you are in 1st/lo/lo or things go boom!

 

[Mr.Bryan]

Pictures

 

[rockrod]

looks good!
Swapping the big parts in is the easy part. It's all the little stuff that takes the most time.

for power steering pressure hose, order the following from Summit:

FLA-FRM16X6AN this screws into the pump
Russell 640380 this screws into the PS box

The hose ends will need to be -06 female AN 90 degree.

I suggest a pair of 620421 from Russell and a 3ft piece of 632600 -06 teflon hose.

You can shorten the hose as needed and make up your own high pressure hose.

 

[Mr.Bryan]

Awesome. I was driving around yesterday to hydraulic shops to try and figure that out. I ordered an art Carr shifter for the trans and will just make some linkages for the t cases.

You guys know of the best way to tie the GM pcm to the ignition so everything switches on and off together?

 

[warpdriv]

You need to find the magic connector behind the glove box. I think it is the H1 connector, white, 14 pins in it. It is basically the plug into the engine harness. I talk about it in my build thread https://forum.ih8mud.com/80-series-tech/403256-another-texas-ls1-swap.html

 

[Kernal]

What might the engine rpms be say at 70mph with this set up with stock gearing??

 

[Mr.Bryan]

Thanks warpdriv. I've been using your thread quite a bit.

Out of curiosity, I didn't see exactly how you were able to set up the fuel line. You ended up running a whole new line right?

My goal is to try and use the existing lines and go with the corvette fuel filter to regulate pressure.

Any of you guys off hand know of any connectors to order for that?

The other thing I'm trying to figure out is how the fuel plumbing works as far as the filter having the return on it, what do I do with the return on the engine? Put them together?

 

[rockrod]

you will have to either update the fuel rail to a later style with the single fitting and run the vette filter, or will have to get a regulator like Kirk did with his LS2 swap.

My motor is a 2006 truck motor so it has the single fitting for the fuel so I used the vette filter - it plugs right onto the fuel rail with nothing special needed. Dorman sells the fittings that will go on the other side of the vette filter to allow hose connections. now that i think about it, i bought an adapter that plugs into the filter supply and provides for a -06 AN fitting. I then used my handy AN flaring tool to flare the stock metal line from the tank (it's -05) and then adapted it with the teflon braided hose. I simply reused the stock return hose and attached it to the fuel return fitting on the vette filter.

Let me know if you want help with figuring out the electrical interface. I have the '96 and newer EWD and and the '93-'94 EWD. I can make an excel spread sheet with diagrams of the IH1 and IH2 connectors behind the glove box and tell you what wire on the vortec harness goes to these connectors. It's about 8 wires IIRC to make it run and get the stock gauges working.

 

[rockrod]

What might the engine rpms be say at 70mph with this set up with stock gearing??

With my 315s, rpms at 70 with stock gearing are ~2000

The OD ratio in the gm trans is pretty steep.

 

[Mr.Bryan]

Ok sounds good. I found a fuel rail on eBay for 45$ so I think I'm going that route.

I would greatly appreceate any help with that wiring. I'm going to poke around warpdrivs thread for the wiring as well.

Also, I saw it somewhere but I can't remember who posted about npt fittings that plugged right into the trans for the cooler lines.

 

[rockrod]

the transmission fittings are 1/4 NPSM.

They are NOT tapered thread fittings. Using NTP fittings may cause the case to crack.

This is what I used:

ATI Performance Products 925137

These will provide you with a -06 AN connection. Get some -06 female to 3/8s hose barb fittings and some oil compatible cooler line and you can plumb the trans into the stock radiator cooler and aux cooler. This will provide more than enough cooling capacity for the 4L60e trans.

 

[Mr.Bryan]

Do any of you guys know the size of the toyota fitting on the fuel line where the hard line connects to the soft line? I'm thinking that this end would plug into what the stock toyota fuel line has then allow me to just put a line from there to the corvette fuel filter.

http://www.summitracing.com/parts/RUS-640830/

 

[rockrod]

I am pretty sure it's a 5/8 inverted flare, same as the power steering box pressure side. I cut it off and flared it to JIC 37 degree and used a tube nut and sleeve to connect to male to make -05 to -06 union. I then made up a piece of -06 teflon hose with AN hose ends to go the vette filter.
here's a pic:

you can see the blue adapter on the filter that converts it to -06 AN.

I am a big fan of AN fittings.

This tool is super handy for putting AN flares on tube:

http://www.aircraftspruce.com/catalog/topages/flaringtools3.php

 

[Mr.Bryan]

I like the idea of the AN fittings as well. Seems nice and simple.

I'm trying out a fitting to go from the existing toyota fitting. The thread is a 14mm x 1.5 and summit had something that looks like it should work and put a -6AN end on that so I can just run a short hose to the fuel filter. Should all arrive Monday. I'll be plenty busy next week. My goal is to drive this thing to the bad lands off road park on the 27th or 28th.

 

[Mr.Bryan]

Thanks again for all the help guys.

I've been doing some searching and can't find anything that describes how to bypass the fuel pump relay. I don't really want to run an additional wire to the pump if I don't have to. Is it as easy as pulling the relay in the engine bay and just jumping two pins?

Rockrod, if you have a diagram for the wiring I would greatly appreciate that. I'm not good at reading schematics and I'm not sure what warpdriv's picture is saying to connect to what.

I think at this point I have almost everything figured out. Just waiting on a bunch of parts to arrive.

I'm going to try and modify the trans pan to give some clearance to the drive shaft this weekend, get the gas pedal mounted and do what ever I can to solve the fuel pump issues.

BTW, any of you guys run into issues with the dip stick hitting the headers?

 

[rockrod]

i downloaded the EWD birfmark uploaded to this site. I can email that to you. I will also send you my excel reference sheet for the IH1 and IH2 connectors. Just remember that my reference sheet is for the earlier non-obd trucks so the wire positioning in the IH1 and IH2 connectors are different.

The EWD is in PDF format. what helped me make my reference chart for the '93-'94 trucks was to search the PDF for IH1 and IH2. This would highlight each connection that runs through these plugs. From there, you can trace the wire and determine what it does in the cruiser, and whether or not it serves a purpose with the vortec motor.

the bigger challenge is taking the 1FZ harness and stripping it of everything you don't need. You will lose about 3/4s of the wires in that harness. I essentially stripped all the tape and tubing from it, removed the unneeded wires, and then retaped it up. There are wires that go to your transfer case and speedo sender that you need to keep (but are buried in with the 1FZ wires). Those wires are needed to keep the CDL control and speedo operational.

 

[Mr.Bryan]

Awesome. Thanks again. My email is xxx

What parts of the 1fz harness would I need to remove if I don't have anything from it? I'm not planning on keeping the speedo and if I can't keep tach, I don't really care either. cdl doesn't matter as I don't have an 80 case.

Basically the only thing i'd like to have working on the dash would be my elocker lights, voltage and temp. The rest I was planning on autometers cut into the dash. Does it cause issues if I don't strip out the wires?

 

[Mr.Bryan]

Also, any of you guys know what direction the trans fluid flow is through the coolers? Trans to radiator to cooler to trans is my guess?

 

[warpdriv]

Awesome. Thanks again. My email is bryank321@hotmail.com

What parts of the 1fz harness would I need to remove if I don't have anything from it? I'm not planning on keeping the speedo and if I can't keep tach, I don't really care either. cdl doesn't matter as I don't have an 80 case.

Basically the only thing i'd like to have working on the dash would be my elocker lights, voltage and temp. The rest I was planning on autometers cut into the dash. Does it cause issues if I don't strip out the wires?

I gutted my dash but kept the lower lights. Since you going with other gauges, you really only need the starter wire. Note get the oil pressure gauge fitting on your engine before you put the engine in.