Eagle Posted January 14, 2006 Share Posted January 14, 2006 To revive an old discussion ... does anyone have a definitive answer as to the truth to the rumour that some 4-cyl MJs came from the factory with an AW4 automatic tranny? Got a 4-cyl 5-speed with a blown clutch and bad tranny. I was thinking it would be a candidate to convert to automatic, but with the 5-speed gearing I need a tranny with overdrive. I also have a parts XJ 4.0L that I could grab the tranny out of, if it'll mate up to the engine. I know the bell housing bolt pattern is different. Is there a different 4-cyl bell housing available for the 2.5L? Does anyone know if I could bolt the AW4 up to a manual tranny bell housing? I know this has been discussed. Has anyone actually tried to recreate this mythical beastie? Link to comment Share on other sites More sharing options...
pingpong Posted January 14, 2006 Share Posted January 14, 2006 Eagle I have heard that rumor too, never seen one though. I have a spare aw4 sitting behind the garage, that I will take a look to see if the bell housing is removable. For some reason I don't think it is. IF it is, it is going to make swapping a 4.3 into my rig a whole lot cheaper. Patrick Link to comment Share on other sites More sharing options...
87manche Posted January 14, 2006 Share Posted January 14, 2006 I saw pictures of one that came in an XJ on NAXJA. So apparently they do exist. That guy was going to get the PN off the bellhousing. Don't know if it ever hapened. Thread was about a month ago, might do well to search over there. Link to comment Share on other sites More sharing options...
pingpong Posted January 15, 2006 Share Posted January 15, 2006 Eagle, I got looking at my spare AW4 tranny, and the bell hopusing is seperate from the main body. So in theory, I don't see why it wouldnt be possible with the right bell housing. Patrick Link to comment Share on other sites More sharing options...
Eagle Posted January 17, 2006 Author Share Posted January 17, 2006 When I get home and can excavate the spare trannies from the snow drifts I'll have a look. I'm assuming that a bellhousing can be redrilled, if necessary, or an adapater made up. Aside from actually bolting the tranny to the bellhousing, there are some other issues and if anyone has thoughts on them, please chime in: * Bell housing depth/input shaft length. I haven't done much with XJ/MJ 4-cyl manual trannies, but back in AMC days the smaller 6-cyl manuals used a shorter bellhousing than the bigger V8 trannies -- by an inch and a half. Is that an issue here? * Pilot bearing diameter -- what pilot bearing would be used, and did the 4-cyl version of the AW4 have a different input shaft? * Torque converter/flex plate: The standard 4.0L flex plate is too large to bolt up to the 2.5L engine, and would not be balanced for it even if it did bolt up. Is there a 4-cyl AW4 torque converter that bolts up to the same flex plate as the 904 auto in the 4-cyl models, or did the 4-cyl AW4 get a special flex plate? How aboiut fitting the torque converter intoi that smaller bellhousing? With manuals, the 4-cyl clutch is smaller. Is there a smaller torque converter for use with the 4-cyl version of the AW4? * What about controlling the tranny? I assume a harness for the TCU can be adapted from a 6-cyl, but does the TBI throttle body have provision for the tranny control output found on the 4.0L throttle body? Link to comment Share on other sites More sharing options...
mjeff87 Posted January 17, 2006 Share Posted January 17, 2006 That guy was going to get the PN off the bellhousing. Don't know if it ever hapened. Thread was about a month ago, might do well to search over there. That was me who was gonna get the P/N, but I never found one visible on the 'bell :oops: I also saw one with my own eyes (it was in the rig that I pulled the 4.56 D30 from). I shoulda grabbed the TCU when I got the axle, too. I went back to get it a couple weeks later and they pulled the XJ and crushed it, AW4 and all...... Jeff Link to comment Share on other sites More sharing options...
Bounty Hunter Posted January 17, 2006 Share Posted January 17, 2006 What about controlling the tranny? I assume a harness for the TCU can be adapted from a 6-cyl, but does the TBI throttle body have provision for the tranny control output found on the 4.0L throttle body? Here you would likely have to get a TPS from a 2.5L auto in order for the TCU to get the input it needs. You can always rig a switch to shift it for the sake of simplicity. Link to comment Share on other sites More sharing options...
Eagle Posted January 17, 2006 Author Share Posted January 17, 2006 What about controlling the tranny? I assume a harness for the TCU can be adapted from a 6-cyl, but does the TBI throttle body have provision for the tranny control output found on the 4.0L throttle body? Here you would likely have to get a TPS from a 2.5L auto in order for the TCU to get the input it needs. You can always rig a switch to shift it for the sake of simplicity. But the 904 isn't electronically controlled, is it? Would there even BE a TPS for it? And if there is, would the output be compatible with the AW4 TCU? Yeah, it can be controlled by a switch or switches, but that only works if the driver remembers to do basic things like unlock the converter when stopping at traffic lights. I'd remember ... my wife wouldn't :( Link to comment Share on other sites More sharing options...
pingpong Posted January 17, 2006 Share Posted January 17, 2006 I was talking with the guy who is doing the fab work on my trail rig, and he said the easiest thing to do for the bell housing is tooo use a lakewood scatter shield, and that way you can drill the holes your self where needed. In my case it would be fro a 4.3 swap. Torque convertor, you might have to go with a custom one, if you can't find a part number. Flywheel might also have to be a custom unit unless you could find part numbers. Patrick Link to comment Share on other sites More sharing options...
Pete M Posted January 18, 2006 Share Posted January 18, 2006 You may not need overdrive as much as you may think. 2.5L/autos came with 4.56 gears. If your 2.5L manual has 4.10s, then, uh, well you can do the math, my head hurts. Jeep on! --Pete Link to comment Share on other sites More sharing options...
Bounty Hunter Posted January 18, 2006 Share Posted January 18, 2006 2.5L/autos came with 4.56 gears. I thought most all had 3.73, just like every other model of 2.5L auto jeep. Link to comment Share on other sites More sharing options...
mjeff87 Posted January 18, 2006 Share Posted January 18, 2006 Only the 2.5's that had an AW4 behind them, not the 904. I guess the OD in the AW4 made the tall gears functional. Jeff Link to comment Share on other sites More sharing options...
Pete M Posted January 18, 2006 Share Posted January 18, 2006 I have found no evidence of MJs ever coming from the factory with 3.73s. That seems to be an XJ thing. And yes, there was no 4.56 in 86. Nor is it a hard and fast rule that 2.5L + auto = 4.56, there are so few of them that we simply don't know. But as far as we can tell, 4.56 was only found behind the 2.5L/auto and no other drivetrain combo. Jeep on! --Pete Link to comment Share on other sites More sharing options...
pingpong Posted January 18, 2006 Share Posted January 18, 2006 I have heard the 4.56's were available with the 2.8 as well, but can't confirm this either. there is a thread on pirate about this in the Hardcore tech section. Seems these aw4 were available behind yota's and zuzu as well. Patrick Link to comment Share on other sites More sharing options...
Pete M Posted January 18, 2006 Share Posted January 18, 2006 car-part.com is usually pretty good with their info and the 4.56 isn't an option until 87. If anyone needs it, the part number for the 2.5L AW-4 torque converter housing is 8350-3706 from my 87-90 parts manual. Jeep on! --Pete Link to comment Share on other sites More sharing options...
Eagle Posted January 20, 2006 Author Share Posted January 20, 2006 Torque convertor, you might have to go with a custom one, if you can't find a part number. Flywheel might also have to be a custom unit unless you could find part numbers. Finding part numbers isn't the problem. The problem is finding the parts that go with the numbers. Link to comment Share on other sites More sharing options...
carnuck Posted February 1, 2006 Share Posted February 1, 2006 I don't know if any MJs did, but I have seen several XJs with AW4 and 4 cyl. One of the trans is sitting in a junkyard in Bellingham, WA, but they think it is solid gold plated or it would've gone into my '86 4 cyl Comanche! The flexplate is different than the 904 one. The 4 cyl got MPFI late in '90 and those are the only ones I saw with the AW4. It uses the same throttle body as the later TJs and CPS as the 4.0L. Wish I'd had my camera with me the last time I saw one of these rigs! Link to comment Share on other sites More sharing options...
Recommended Posts
Create an account or sign in to comment
You need to be a member in order to leave a comment
Create an account
Sign up for a new account in our community. It's easy!
Register a new accountSign in
Already have an account? Sign in here.
Sign In Now