Difficulty of swaping a transmission.

[EagleJoe93]

Hi everyone.  I was curious as to how difficult it is to swap an automatic transmission with a manual transmission in an AMC Eagle.  Looking around on Eaglenest, I found a post with a variety of manual transmissions that would work.  But I don't know how difficult it is to configure all of the linkages (particularly the clutch linkage) and what parts may be needed.  Would this be a bolt-on process, or would drilling, welding, etc. be needed?  It is something my Dad is curious about as well.  If it isn't to complicated, I may consider buying a good Eagle with an automatic (since they seem to be the most common) and converting it when I have the time and money.

Thanks for the help everyone

[eaglefreek]

I've never done it, but have owned both a manual and an auto Eagle. Everything should be a "bolt on". The Eagles' clutches are hydraulic so no linkage like you would see on an older car. You would need everything from a donor vehicle though. Clutch pedal assembly, master cylinder, slave cylinder, flywheel, clutch, bellhousing, transmission and shifter.

[EagleJoe93]

Thank you for the reply.  The cars I've been looking at all had the 258 c.i. engine.  Do you know if all of the needed part are interchangeable between all of the years Eagles were made?

Thanks again.

[eaglefreek]

All 6cyl. cars. The 4cyl. use different bellhousings and transmissions.

[DaemonForce]

Most of the trouble you encounter will be uninstalling your current transmission. I recently finished a straight automatic swap and it took me 21 days because I didn't know what I was doing. The process is too lengthy on the automatic uninstallation end to compare but it's still fun. I like how I need a dozen tools to do this and only 2 in my Snap-On set can actually do anything.

Time: 3hrs 20min

Shifter cover: + screwdriver - 2 screws, 8mm screwdriver - 2 screws
Shifter linkage: 15mm wrench
Shifter guard plate: 3/8 screwdriver - 4 screws
Transfer case & transmission guardplates: 9/16 wrench & 16mm socket - 9 bolts
Transmission pan(drain): 13mm wrench - 14 bolts
Transfer case speedometer cable(drain): phillips screwdriver
Drivelines: 8mm wrench - 16 bolts
4x4 shift linkage: 9/16 wrench
Transfer case: 9/16 wrench - 6 nuts
Vaccuum flange: 12pt 10mm wrench - 1 bolt
Flexplate cover: 9/16 wrench - 4 bolts
Torque converter: 14mm wrench - 4 bolts
Starter: 9/16 wrench - 2 bolts
Starter cable: 3/8 wrench
Carb linkage: vicegrip
Transmission cooler lines: 13mm wrench & 16mm crowfoot, - screwdriver
Bell housing: 9/16 socket - 3 bolts, 9/16 wrench - 3 nuts, 5/8 socket - 2 bolts

All of this is incredibly easy assuming you don't have to deal with anything insane like I did:
LOTS of mud/grease that took me a few days to scrape and clean
Stuck transfer case nut in an awkward place that had to be chiseled off
Several degraded nuts and bolts
Huge ATF mess
A "professional" mechanic that constantly stripped bolts(and sudden trips to machine shops to fix this)
Unclean work area(pine needles and grease everywhere)
Kids running around moving random bolts/nuts

Reinstallation took me 20x as long because of this mess. Installing a clutch and bolting in a manual transmission would be so much easier than what I just went through and it would be far more rewarding. If I ever get my hands on a 4WD Borg Warner T-5, I'll make a photo/video documentation of it all for everyone. I don't know what it is about these Eagles but even with modern stop and go traffic, I can't even bat an eye when I say a manual transmission belongs in these cars. Period.

All 6cyl. cars. The 4cyl. use different bellhousings and transmissions.

Tell that to my car. What I just described above is me eviscerating a Chrysler A-904 transmission that is remarried to a 258 engine. The real pain is reading in every manual that it's what goes to a 4cyl, not a 6.

[captspillane]

I'm converting most of my automatic Eagles to manual. The 998 is actually a great automatic transmission, but they fail over time and get terrible gas mileage. They rely on fluid pressure to work and gaskets to maintain that fluid pressure. Mileage aside they will fail after those critical gaskets age for 20 years. A gently used T5 will last forever. I get 26 to 29 mpg out of my 258 T5 and only get 18 to 22 out of my automatic Eagles. Its a very worthwhile switch.

A T5 from a CJ is very easy to come by. Professionally rebuilt units are being sold for about 600 dollars. A good used one is often being sold for about 150 dollars. The rebuild kit costs about 115 dollars. A factory service manual telling you how to rebuild one is readily available for about 30 dollars. Any SR4, T18, T4, or T5 bellhousing will work.

You will need different flywheel bolts to go with your new 258 flywheel. The 6 bolts holding the automatic flexplate on are shorter. The bolts from a manual 4.0 flywheel will work with a 258 flywheel, but do not use a 4.0 flywheel. Its too thin and isn't compatible with your 258 starter.

The best axle ratio to use is 3.54. This is very hard to find. Only 4 cylinder Eagles had them from the factory. There is three different front axle casings so swapping carriers doesn't always work. Alot of station wagons had 3.07 gears that are decent too. Any other ratio is a miserable driving experience.

You will need to drill three holes in the firewall for the clutch master cylinder. It has to fit under the brake booster and its very tight there. The best way to do this is to copy the pattern from someone who has one. For my conversions I made a template that shows the location of these three holes in relation to the steering shaft bolts and the fusebox. Since the output shaft is able to spin, only the center hole is actually important. Even that isn't critical since I do think you could be up to a half inch off and still have a working clutch. I bet you could just look at a picture of the firewall and be okay.

The pedal assembly is largely the same. The clutch pedal is essentially just bolted to the side of the same steering housing as an automatic. If you trimmed your brake pedal so that it wasn't so wide it would work. Its possible to then take another automatic brake pedal and make that into a clutch pedal. Of course the best bet is still to find someone who has an Eagle or Spirit manual pedal assembly. Four cylinder Spirits have the same clutch master and slave cylinders as Eagles and will work as is. The Iron Duke and 258 have different bellhousing bolt patterns but everything else is exactly the same.

6 cylinder Spirits have a mechanical clutch linkage. Those pedal assemblys will need to be modified to work. That would be as easy as drilling a hole and using a long bolt and three nuts as a horizontal stud.

Do not try to install a Spirit mechanical linkage in an Eagle. It simply won't work. It won't clear the front axle. Its also unable to adjust enough to accept a ten inch clutch plate. Only Spirits used the 9 inch clutch plate and I couldn't find anyone who still sells them. I burned out a new ten inch clutch before cursing and switching my Spirit to the hydraulic system.

The next hardest part is finding a remote clutch resevoir. Just about every clutch master cylinder has its resevoir integrated into itself, but those won't fit in our cars. Don't bother trying to use a cherokee or YJ clutch master cylinder, it definately won't end well. Once you get your Eagle cylinder it will have two holes at the rear. You'll have to bend your own 3/16 double flare hydraulic tube from those holes to a remote resevoir and to the slave cylinder.

Its true that you need to match the slave cylinder and flywheel to the transmission if you use something other than a T5, like an AX15. The rest of the hydraulic system must stay the same, however. Only the original Eagle clutch master cylinder with remote resevoir will fit on our firewall. Period.

Its very hard to find a replacement remote resevoir except for an original factory unit. The only aftermarket one I know if is made by Wilwood. It has a hose clamp connection on it and you'll have to connect your 3/16 double flare tube to hose for it to work. Try to get this from an Eagle too. If anyone finds a better unit I want to know about it.

My 1981 6 cylinder and all my four cylinder manual cars have the nice remote resevoir. My 1983 6 cylinder, however, had a crappy plastic tube from the factory. The tube cracked and left me stranded within a week of getting that car. Avoid or replace the tubes if you get one with your donor Eagle.

There needs to be a flexible hydraulic hose between the car body and the slave cylinder. For that I use the rear brake hose meant to bridge the gap between the car body and the rear axle. That flexible line has one input and two outputs, but a plug easily takes care of the second output.

[captspillane]

All 6cyl. cars. The 4cyl. use different bellhousings and transmissions.

Tell that to my car. What I just described above is me eviscerating a Chrysler A-904 transmission that is remarried to a 258 engine. The real pain is reading in every manual that it's what goes to a 4cyl, not a 6.

The 904 was used for decades before Chrylser decided to modify it with an enlarged planetary assembly. They made very few upgrades to it and the necessary changes to the case casting and then called it a 998. All of our 6 cyllinder Eagles have a 998 behind them with the AMC bolt pattern. All the four cylinders have a 904 with Chevy bolt pattern. Both use the same rebuild kit and same gaskets throughout. Most companies don't bother labeling their rebuild kits as 998 kits because the 998 was a relatively rare variation on the same 904 transmission. Most transmission guys can't tell the difference and don't care.

You just removed a TF998 from your Eagle and called it a TF904.

[carnuck]

All 6cyl. cars. The 4cyl. use different bellhousings and transmissions.

Tell that to my car. What I just described above is me eviscerating a Chrysler A-904 transmission that is remarried to a 258 engine. The real pain is reading in every manual that it's what goes to a 4cyl, not a 6.

The 904 was used for decades before Chrylser decided to modify it with an enlarged planetary assembly. They made very few upgrades to it and the necessary changes to the case casting and then called it a 998. All of our 6 cyllinder Eagles have a 998 behind them with the AMC bolt pattern. All the four cylinders have a 904 with Chevy bolt pattern. Both use the same rebuild kit and same gaskets throughout. Most companies don't bother labeling their rebuild kits as 998 kits because the 998 was a relatively rare variation on the same 904 transmission. Most transmission guys can't tell the difference and don't care.

You just removed a TF998 from your Eagle and called it a TF904.

Planetary and rear band were upgraded and 1st/2nd ratios changed to lower to improve takeoff power. My beef with the 998s is snapping the converter neck off. So far 7 that I know of. Replace them with a billet welded converter and the problem goes away.
   Calling it a 999 (same as YJ and TJ) will get the correct rear band. In fact, unless I tossed it already, I have the case from a TJ with the crank sensor hole I was going to build up to run EFI before I noticed the AW4 was narrower.

[captspillane]

Calling it a 999 (same as YJ and TJ) will get the correct rear band. In fact, unless I tossed it already, I have the case from a TJ with the crank sensor hole I was going to build up to run EFI before I noticed the AW4 was narrower.

I dislike the AW4 and would like to stick with the torqueflite series so that I become specialized in rebuilding them. Do you know what year TJs and YJs had the 999 with crank position sensor in the casting? Thats something I will have to start shopping for. I'll buy your case if you live close enough.

[amcinstaller]

aw4 is actually an awesome auto, the main beef jeep guys have is their amazing ability to soak power and mileage from the wheels. in terms of crawling, and even racing, it is definately worth using. aw4 is found in toyota supras, and the supra guys have figured how to put shift kits in them, while jeepers are praising the longterm longevity of them.

[carnuck]

I'm near Seattle (pretty close to Mojobean ) If you want O/D you could do a 42RE, but I dislike them due to weakness and power consumption. Output shaft is longer so a 1" spacer is needed to put an Eagle tcase on them.
   AFAIK, all fuel injected ('91 up) YJs and all TJs are on the bell. Mine is from a '00 Wrangler.