89 GW OBD1 4.0 swap ?s

[GWag89]

Ive been looking into swapping a 91-95 OBD1 4.0 into my 89 Grand Wagoneer. I understand this has been done before and I have some questions. I know i can bolt the 4.0 to the TF727 but I dont know what combination of flex plate and torque converter to use. From what i understand it is possible to bolt the 4.0 42re flex plate to the TF727 TC.

Question 1, will a 4.0 42re flex plate work with the starter that bolts to my 727?
Question 2, will the stall speed of the TC designed to work with the 360 work well with a 4.0?

If anyone has a proven combination of parts or a link to build thread I would appreciate that very much. Im looking to keep this a junk yard swap.

[Stuka]

One issue is the intake manifold will hit the brake booster. So either a body lift is required, or convert over to hydro boost brakes. Or find a smaller diameter booster. Some swap in the intake manifold from a 2000's 4.0, which is rounded and just barely clears the stock booster.

Also know you will need entirely new engine mounts. The i6 mounts are very different from the v8 mounts.

You will also need an ECU from a manual trans equipped 4.0 since the 727 is not electronically controlled.

But just about every swap I have seen people use the stock AW4 that came behind the 4.0. Its an overdrive trans, and IMHO is a better trans for use with an i6 than a 727. The 727 has more parasitic power loss than the AW4, and no overdrive.

[tgreese]

One issue is the intake manifold will hit the brake booster. So either a body lift is required, or convert over to hydro boost brakes. Or find a smaller diameter booster. Some swap in the intake manifold from a 2000's 4.0, which is rounded and just barely clears the stock booster.

Also know you will need entirely new engine mounts. The i6 mounts are very different from the v8 mounts.

You will also need an ECU from a manual trans equipped 4.0 since the 727 is not electronically controlled.

But just about every swap I have seen people use the stock AW4 that came behind the 4.0. Its an overdrive trans, and IMHO is a better trans for use with an i6 than a 727. The 727 has more parasitic power loss than the AW4, and no overdrive.

The AW-4 will also give you the provision for the crank position sensor (CPS), already in the bell housing.

What's the spline count of the AW-4 compared to whatever is behind the 727?

[Stuka]

One issue is the intake manifold will hit the brake booster. So either a body lift is required, or convert over to hydro boost brakes. Or find a smaller diameter booster. Some swap in the intake manifold from a 2000's 4.0, which is rounded and just barely clears the stock booster.

Also know you will need entirely new engine mounts. The i6 mounts are very different from the v8 mounts.

You will also need an ECU from a manual trans equipped 4.0 since the 727 is not electronically controlled.

But just about every swap I have seen people use the stock AW4 that came behind the 4.0. Its an overdrive trans, and IMHO is a better trans for use with an i6 than a 727. The 727 has more parasitic power loss than the AW4, and no overdrive.

The AW-4 will also give you the provision for the crank position center (CPS), already in the bell housing.

What's the spline count of the AW-4 compared to whatever is behind the 727?

Depends on the year. Pre-90 is 21, post-90 is 23. TF727 from an FSJ is also 23.

[GWag89]

thanks for the replies.


My wag has a blown 360 in it right now. I originally wanted to replace it with another 360 but after searching for some time i find that they are becoming scarce in Un-rebuilt form. there are a few other reasons I am steering clear of another 360 but thats not what this thread is about

I have a 999 trans cross member and T case skid that are not compatible with the AW4. I would like to keep the skid and the 727. My transmission works beautifully and so does the NP229 T case. both have been well maintained and lightly used by the previous owner. I would like to keep what I can since it already works and adapt the 4.0 to work with what i have. My wagoneer is making the transition to "antique plates" which means that it wont be seeing the pavement unless its heading to a local trail. Speed and MPG are a secondary priority

Any ideas on what Flex plate and Torque converter to use?

[Stuka]

As far as I know, the torque converter is the same for the 360 and 258. As for flex plate, it has to be a flexplate for the 4.0HO because of the CPS. A 258 flywheel will not have a CPS slot on it.

BTW: There was only one cross member used for 80+ FSJ's. Doesn't matter if it was a manual, 727, 904, or 999. They just used different holes on the frame to adjust depth. And they never came with a t-case skid, unless you have an aftermarket one.

[GWag89]

The 999 cross member Im referring to is an aftermarket skid plate offered in the vendor section by 999 offroad. I have a decent amount of money invested in this part and i plan on keeping it.

Thanks for the advise on the TC. That is a major relief because TC are not cheap.

You mentioned the engine mounts being different. Would i be able to use the 258 mounts to bolt the 4.0 in

[Stuka]

Yes 258 mounts and 4.0 mounts are essentially the same as far as the frame mount goes. The mount that goes between the engine and frame mount is a bit different. But those are just a part you buy.

And I thought you meant the 999 transmission I get what you mean now.


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[carnuck]

One issue is the intake manifold will hit the brake booster. So either a body lift is required, or convert over to hydro boost brakes. Or find a smaller diameter booster. Some swap in the intake manifold from a 2000's 4.0, which is rounded and just barely clears the stock booster.

Also know you will need entirely new engine mounts. The i6 mounts are very different from the v8 mounts.

You will also need an ECU from a manual trans equipped 4.0 since the 727 is not electronically controlled.

But just about every swap I have seen people use the stock AW4 that came behind the 4.0. Its an overdrive trans, and IMHO is a better trans for use with an i6 than a 727. The 727 has more parasitic power loss than the AW4, and no overdrive.

The AW-4 will also give you the provision for the crank position center (CPS), already in the bell housing.

What's the spline count of the AW-4 compared to whatever is behind the 727?

Depends on the year. Pre-90 is 21, post-90 is 23. TF727 from an FSJ is also 23.

To run the FSJ tcase on an XJ 23 spline AW4 you need the 1 inch clocking ring/spacer (actually 15/16" to 7/8") I got mine from Partsmike.com and I plan to find out if the ZJ AW4 (93 only) is the rumored 1" shorter once I get the parts rig to the shop. The AW4 is good if you have 3.31 or lower gears. 3.55 is better.
I currently have 3.73 in my Comanche with AW4 (which is 21 spline and a .70 O/D whereas the 23 spline are .75) and 3.73 gears with 33" tires and it sucks up the power on takeoff (top speed of 70+ mph isn't too bad but 12-14 instead of 17 mpg highway sucks) If you have the XJ style starter then it will bolt to your 727 converter with the 42RE or 32RE flexplate (it's the same) I even have a 999 case with the CPS in it in my parts for sale pile.
The bolt pattern on the 727 and 999 converter changed to an even offset with the XJ starter and the flexplate teeth are 3/8" closer to the motor so the Motorcraft starter won't work (too deep).

[carnuck]

Yes 258 mounts and 4.0 mounts are essentially the same as far as the frame mount goes. The mount that goes between the engine and frame mount is a bit different. But those are just a part you buy.

And I thought you meant the 999 transmission I get what you mean now.


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999 = 32RH for hydraulic or 32RE for electronic (computer) controlled shifting.

The bracket on the frame for the 6 cyl is different. I have swapped several each way and they won't work for one another in FSJs. CJs are a different story where only 1 side is the same V8 or 6. I suggest using the Energy Suspension CJ 6 cyl poly mounts because I kept tearing up the stock ones just towing my trailer.


I'll probably use the Grand Cherokee frame mounts to put the 4.0L in the '68 Travelall when I get time.

[carnuck]

thanks for the replies.


My wag has a blown 360 in it right now. I originally wanted to replace it with another 360 but after searching for some time i find that they are becoming scarce in Un-rebuilt form. there are a few other reasons I am steering clear of another 360 but thats not what this thread is about

I have a 999 trans cross member and T case skid that are not compatible with the AW4. I would like to keep the skid and the 727. My transmission works beautifully and so does the NP229 T case. both have been well maintained and lightly used by the previous owner. I would like to keep what I can since it already works and adapt the 4.0 to work with what i have. My wagoneer is making the transition to "antique plates" which means that it wont be seeing the pavement unless its heading to a local trail. Speed and MPG are a secondary priority

Any ideas on what Flex plate and Torque converter to use?

Another V8 option is 304 with pretty much the same fuel economy as the 6. Use a 42/32RE flexplate with the XJ style starter. 32RH/9xx is offset converter pattern like the early 727.

Note that the 6 cyl trans crossbar is 5" back on the frame from the V8 one as well.

[GWag89]

Since the brackets off the frame are different for an i6 Im going to need to find a set that will work. Is there a vehicle i can snag these off of (other than a i6 fsj)? if nothing is redaly available i have no problem fabricating my own brackets but id rather use as many factory bolt in parts as possible just to keep things simple.

This is my first round of questions concerning this swap. Once i get the peices together Im sure questions will arise

[Stuka]

I cannot think of anything else that has mounts that will work.

Carnuck brought up a good point, the cross member does have to be move back to the rear holes. Be sure your skid plate will work there.


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[GWag89]

Thanks for the heads up on the cross member. I will check that out when i get home. Looks like i will need to fab some brackets unless i can find some used ones off an i6 fsj in the parts for sale section on here. I have seen them on ifsja a time or two but it dosnt seem to be a very common part to salvage and sell

[carnuck]

In case it wasn't obvious, the driveshafts need swapping too.

[GWag89]

Seems like the 42re flex plate bolted to my 727 tourqe converter is going to be my best bet. My 727 uses the late style xj starter so that should work with this combo if my info is correct

[carnuck]

Just check the holes in your V8 flexplate are evenly spread. The earlier ones weren't

[GWag89]

In research I've found that some of the 42RE flex plates have offset tourqe converter holes. Only slightly offset from the 90* bolt holes on the 727. Im going to look at some parts stores online and see if i can make a destinction between the 90* plate and the offset one

[GWag89]

Found this thread in regards to the flex plate/ tourq converter bolt pattern. Its not the most informative thread but he info seems legit.

96 42re has the 90* bolt pattern.
93-95 42re has offset bolt pattern.

http://www.jeepin.com/forum/showthread.php?t=42218

[GWag89]

I got a 32re flex plate from the local parts store and it's a NO GO.

It bolts to the 4.0 perfectly. The offset for the starter is good and the plate is neutrally balanced as it should be. The torque converter holes are 90* offset

Only problem. .. It doesn't bolt to the tf727 torque converter. The bolt pattern is a different size. Only by about 1/4" or less. But either way it doesn't fit

Now I'm stumped as to what I should do. Maybe try a 42re plate or grind the imbalance weight off a 258 flex plate (if that is even possible to do safely and without damaging the engine)

Another option is throw a 4.2 crank and Rods in my 4.0 and use an i6 wag flex plate

Any ideas??