AW4 Transmission Swap

[SC/397]

For those with AW4s, other than having an overdrive, how do you like it compared to the 3 speed auto it replaced? (in terms of gear ratios, gear spacing, shift patterns, lock-up in the lower gears...)
Thanks.

I can tell you that with my Javelin I had a 3 speed auto with a 2.87 rear end and a 304 and it was pretty boring and slow. I swapped in a AW4 and 3.54 rear end which made the final drive ratio 2.79 in overdrive. The car has the best of both worlds now. It really moves out nice and I can run it on the highway at 75 mph without killing the engine with rpm's. It is the best thing that I ever did to the car.

['89_Wagon]

Just got done pulling the A727, flexplate, and all the other stuff out. I have the transmissions side by side and started comparing linkages and what not.

Good news, the shifter lever on the AW4 is the same distance from the bellhousing as the A727. I think that will make things easier since I can use the same length shifter rod. The goal is to avoiding welding so I'll be searching for parts. Hopefully something fits the bill.

The kick-down cable looks like it can attach directly to my TBI throttle arm. I just need a way to mount the cable. It seems to use the same type of mount as the engine throttle cable.

As for the T-case.... the vacuum line on the 4WD switch just needs to be lengthened..fairly straightforward. But, I need to think about the HI-LO lever. I don't know what to do about that just yet.

Will follow up with pictures and a check list for transmission removal. There was some little stuff to look out for.

['89_Wagon]

Flexplate off to SC/397 for balancing. Huge thanks!

My NP229 housing needs to be resealed. I plant to use loctite 515 to seal this. Any other tips when taking this apart? I'm not replacing all the seals and rebuilding it... just resealing the main housing because it leaks.

Also, I was never able to switch it into LO. Is there a way to bench test this?

Someone had dropped the transmission before (Missing and different bolts on the x-member) and replaced the torque converter. It looks pretty new. My transmission never really grabbed in 1st and 2nd... just 3rd. It made for some scary moments trying to merge with traffic. I suspect the torque converter was replaced in an attempt to fix that, but I think the real issue is that the A727 needs a rebuild. It had enough trans fluid and I adjusted the throttle rod to see what effect it had. While it got a bit better, nothing fixed it. Too much slippage. Also adjusted the bands as well to spec (book neglected to mention the 1/2? turn out). Curious what you guys think.

['89_Wagon]

Check list for transmission removal. I removed the T-Case separately just to make it easier to get at the other stuff.

1. Disconnect battery
2. Disconnect transmission lines at transmission
3. Disconnect vac line to 4WD switch/motor
4. Detach E-Brake cable from transmission cross member. I had to slice open
the plastic sleeve to reveal the section where a wrench can grab and brace
the cable so the adjustment nuts can be removed. This is relevant to the driver's side mount. The passenger side is just a rod.
5. Disconnect driveshafts and remove.
6. Disconnect throttle rod at or near transmission
7. Disconnect shift linkage at transmission
8. Disconnect Hi/LO linkage
9. Disconnect speedometer cable on transfer case
10. Disconnect NSS switch
11. Remove exhaust from headers back
12. Remove starter
13. Unbolt dipstick tube and remove by pulling out. Bolt is at the top of transmission bell housing and is a bit of a pain.
I dropped the t-case to get better access. Place plan below to catch trans fluid. Alternatively, drain transmission before removal. I wish I did.
14. Unbolt attached hardlines and vacuum line brackets
15. Drain transfer case
16. Remove flexplate inspection cover and unbolt flexplate
17. Connect transmission jack
18. Unbolt transmission from engine
19. Unbolt cross-member from frame and transmission and remove
20. Move transmission rearward then lower.
21. Unbolt flexplate from engine.

['89_Wagon]

Here are some pics.

Flexplates side by side


AW4 Shifter. The post is about 5/16 in diameter or 8mm.


A727 linkage lower right. The top one is the throttle valve. Notice the orientation of the posts. Vertical vs horizontal on the AW4


A727 shift linkage distance from front of bell housing..11"


AW4 shift linkage distance from front of bell housing...also 11". Therefore, I'm planning to use the same length shifter rod at transmission... 8 3/8" from eye to eye.


AW4 Throttle cable connector

[SC/397]

We got the AW4 flex plate balanced to match the 360 flex plate this morning. It took 601 grams of weight located in the same position as the as the weight on the 360 flex plate relative of the crank mounting holes. We actually had to weld weights on both sides of the flex plate to make it work out.
It took a hour but the guy only charged $45.00.
('89_Wagon owes me a couple of beers for the 4 hours time that I have in to his project.. LOL!)
727 flex plate left, AW4 flex plate right

IMG_2561 by Rick Jones, on Flickr


This is a picture of the early 727 flex plate up to 1988 on the right and late 727 flex plate on the left after 1988.

IMG_2559 by Rick Jones, on Flickr


Here is a shot of the Late 727 flex plate and the AW4 flex plate. The fore and aft ring gear position is the same but the off-set of the torque converter mounting location is different so, just drilling new holes in the 727 flex plate for the AW4 torque converter would not have worked out without some work.

IMG_2560 by Rick Jones, on Flickr

['89_Wagon]

Many beers and many thanks!

It's nice to see that side by side comparison of the flywheels.

['89_Wagon]

Updates

Got the flexplate bolted up! I torqued it to 105 ft pounds and used blue loctite. I could not find the spec in the manual for the GW but I was able to find it for the Cherokee. Is that the right spec?



Word of warning, the nut on the end of the shifter arm needs a lot of penetrating oil and snaps easily. I found out the hard way. To my knowledge, no one sells a replacement shaft and it would require dropping the valve body to replace it anyways. I resorted to tack welding it on. Looking back, I would leave the shifter arm on the AW4 and just drill out the 1/2" hole from there.




Since the shifter arm is about the same distance from the front of the bellhousing as the A727, I'm reusing the GW shifter rod and modifying the AW4 shifter arm to suite.

1. This setup uses a 5/16 tie-rod end with a e-clip securing the shifter rod to it.
2. This tie-rod needing some grinding in order for the notch on the shifter arm to reveal itself so the e-clip could attach.
3. A 1/2" hole was drilled into the shifter arm and a nylon sleeve was inserted.
4. Nylon washers and nuts hold everything together.

It feels solid. I might try to find a replacement fro the tie-rod end though. After putting it together, the tie-rod eye is the only point with some play. But I'm thinking this setup will allow the shifter arm to pivot as needed.







Next up is bolting the AW4 to the engine and then modifying the cross member.

[wiley-moeracing]

Lets hope the shift shaft seal does not leak....

['89_Wagon]

Lets hope the shift shaft seal does not leak....

Yep.. Making the best of a bad situation. I was concerned about that too so I let things cool off between short passes. Hopefully that did the trick. Another option would be to jb weld.

[pickledtoast]

just drilling new holes in the 727 flex plate for the AW4 torque converter would not have worked out without some work.

.280" spacers by my earlier measurements.

keep up the excellent updates!

[pickledtoast]

3. Brake “sense” wiring: White/pink* wire from TCU. I had some confusion about whether this was switched to 12+ or ground. In 96, the circuit switched to ground. In 97, the circuit seems to switch to 12+. From there, they both operate the same, open circuit means brake on, closed circuit means brake off. This “sense” circuit locks/unlocks the toque converter.

I'm running a '97 TCU in a <96 trans (with newer 97+ NSS swapped in, but still running the old reed style single VSS). The '97 brake sense gets switched to ground, open when brake pedal pushed. if this is to be believed:

https://cardiagn.com/4-0l-transmissi...cherokee-1997/

I'm working with Nick at Niftyshifter, will be testing one of his Pro's eventually.

[pickledtoast]

At first, I was hoping to use the GM TPS reference wire and I might still do that. But, I did some initial comparisons between the GM and Jeep sensors at 0%, 50%, and 100% throttle and the differences were large enough that I though it best to run the Cherokee sensor first and test the GM sensor later... one less potential issue to have at the start. Although, I tested the Cherokee sensor on the bench with its full sweep. When installed, the sweep is much shorter. I'll run the test now with it installed just to see what the values come in at.

From your testing, what were your voltage/throttle percent values for TPS?

['89_Wagon]

Transmission is in! Forgot to install the transmission spacer/flexplate cover before bolting down the flexplate so I had to do that over again. Also, I had to shorten the top two mounting bolts since they bottom out. I took off about a 1/4". Here are some pics.



I drilled the holes out way too big on the cross-member, too embarrassing show.... so I covered it up You can see that the transmission mount studs are pretty far forward in the cross member. But this way, the rear mounting points can be used on the frame to bolt the cross-member to.




I cut the nub off the throttle rod bracket to make room so I could mount it like this. The nub is where the transmission throttle rod would pass through on the Wagoneer's bracket. Then I drilled the mounting holes out a bit bigger. Last, secured using the transmission bolt. I had to use about 3/4" spacer/washers on the bolt since the bracket does not sit flush with the transmission. It works. Thinking of other options that would keep it from walking/twisting. Also, the shifter is a bit too firm and needs a bit of force to shift gears. The shift positions are not aligned with markers on the column... the indicator makes it to about N or D when the transmission is in the L? position. I think I can kill two birds with one stone by somehow extending the arm on the transmission.... get more leverage and line up the indicators on the column.




Note the bolt holes. Look near the closest jack stand. The A727 uses the front 4 set. The AW4 uses the rear 4 bolt holes.



Next up is bolting up the tcase and measuring for driveshafts.

['89_Wagon]

From your testing, what were your voltage/throttle percent values for TPS?

These were measured on a bench. Values are pretty much the same in the higher range, it's just the lower %'s I'm worried about. Note the 0% values. I bought a cheap one just to test, so that could also be a factor. I'm really hoping I can just tap into the GM sensor on the TB since that would be cleaner.

Voltage should be increasing with throttle position on both sensors, and I think voltage increases with resistance (holding everything else constant) so this checks out at least the directional values. The Renix AW4 systems might be the opposite though, for those that may be interested in this swap.

AW4 TPS
0% - 360 Ohms
50% - 4,400 Ohms
100% - 8,300 Ohms

GM TBI TPS
0% - 1,400 Ohms
50% - 4,500 Ohms
100% - 8,300 Ohms

Anyone else measure this?