Gary57 Posted October 6, 2014 Share Posted October 6, 2014 I have a 87 Comanche with 4 cyl. and 4 speed, 2wd and want to change to an automatic. What transmission would I need to make the change over as painless as possible? I also want to change to power steering as this has manual. What steering unit will I need? Thanks Gary Link to comment Share on other sites More sharing options...
thejim42 Posted October 6, 2014 Share Posted October 6, 2014 Changing to an auto without changing your gears will make your truck a dog without changing the gearing. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 6, 2014 Share Posted October 6, 2014 The A904 auto is a decent one from the earlier models and has no electronics to worry about hooking up. It is a lighter duty version of the Chrysler TF727 and was used behind slant 6's and small v8's in Chrysler products. If you do a little research there are a couple upgrades you can do to them that are bolt on that improve shifting and durability. I have a 4wd one sitting in one of my parts vehicles that I might use in a future build. Good luck and let us know what you figure out. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 6, 2014 Share Posted October 6, 2014 I forgot about the power steering question. I started with the same platform as you. 87 2.5 4speed 2wd no power steering. You should have a dummy pulley in the place where your p s pump should go. The 87 has a remote resevior so you'll need a new pump, resevior, high and low pressure lines and the gearbox. This is a good time for an upgrade so research that before getting the gearbox. It will bolt right in with the same hardware and steering shaft. This isn't a hard upgrade to do. My biggest issue was that the resevior is no longer available and I couldn't find one anywhere else so I had to improvise. I think they are available now. That should make for an easy install for you. And it is probably the best upgrade I ever did to my MJ. Link to comment Share on other sites More sharing options...
Minuit Posted October 6, 2014 Share Posted October 6, 2014 The AW4 (the auto trans behind the 4.0) was available with the 2.5 for a short period of time. If you can find a bellhousing (or a complete trans) for the AW4 that matches your GM bolt pattern, you might think of swapping it it. Its overdrive will help on the highway for sure. If you can't find one (they are quite rare) the TorqueFlite A904 was the only auto for XJs 84-86 and 86 MJs and will work just fine. It's also not electronically controlled like the AW4 is. As it was said, a 2.5/4spd truck should have a 3.55 final drive gear ratio. With the 2.5 and an automatic, 3.55s will be a horrible nightmare to drive. The typical final drive ratio for 4 cylinder automatics was 4.56. This will be a necessary change unless you want to drive your truck on lawnmower tires. (don't do that) Link to comment Share on other sites More sharing options...
Gary57 Posted October 6, 2014 Author Share Posted October 6, 2014 Thanks guys I now have a starting point. Another question would a engine and drive train from a newer Dodge work under mine? Gary Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 6, 2014 Share Posted October 6, 2014 Here is your trans.......and related. http://carbondale.craigslist.org/cto/4691210856.html Link to comment Share on other sites More sharing options...
mvusse Posted October 7, 2014 Share Posted October 7, 2014 Older YJ Wranglers also used the A904, but they will clock the transfer case up a little higher. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 7, 2014 Share Posted October 7, 2014 There is no Dodge drivetrain that will bolt up. I'm not sure where youre heading with that though. It would take a lot of time and custom fabrication to make any Dodge drivetrain work in your truck other than the 2.5 engine that was offered for a while in the Dakota. And as was said, the 3:55 gearing in your truck won't be very happy to drive. You could source an 8.8 out of an explorer with 4:10 gearing (and rear disc brakes!) You most likely won't find much of anything that will fit that has 4:56 gearing unless you buy new gears and have them installed. I think though that 4:10's would be OK in your application, and the 8.8 would be a fairly easy swap to someone with some welding skills ( though this can be cheaply outsourced ). To find some of the parts you could look on www.car-part.com Link to comment Share on other sites More sharing options...
Gary57 Posted October 10, 2014 Author Share Posted October 10, 2014 I have found an 85 & 84 Cherokee both 4wds and v6 engines that I think will solve my problem on both the steering and automatic. I will just have to change the truck to a 4wd using the drive line from the Cherokee. Is the power steering brackets the same on the v6 as the 4 banger? Link to comment Share on other sites More sharing options...
Jeep Driver Posted October 10, 2014 Share Posted October 10, 2014 I have found an 85 & 84 Cherokee both 4wds and v6 engines that I think will solve my problem on both the steering and automatic. I will just have to change the truck to a 4wd using the drive line from the Cherokee. Is the power steering brackets the same on the v6 as the 4 banger? No. And there is a change from TBI and MPI, either the mounts/brackets are different or the pulleys are different. Either way I'm about to find out myself as I'm converting a MPI intake to TBI on my engine build. And there is a third change after 96-97. Also, the serpentine or V-belts are different in the early years......depending on what you have or get. Just be aware......you may have to change pulleys. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted October 11, 2014 Share Posted October 11, 2014 84-85 the 2.5 was carbureted. They went to TBI in 86 and MPI in 91. Link to comment Share on other sites More sharing options...
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