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Harmbl 01-10-2012 08:21 AM

Engine swap
I have an 88 YJ 4.2L, 220,000 miles body anf frame good, Engine was knocking so pulled and got one from a junk yard from a 79 4.2L with 88,000 miles. I have been trying to put it in and I get as far as the input shaft into the pilot bushing and it will not merry up to the beel housing. It gets anout an inch away and thats it. I used the clutch and pressure plate and fly wheel from the 88 so it should slide in. Any ideas??? Thanks

1SAS 01-10-2012 11:32 AM

Before you put in the transmission, have you measured the ID (inside diameter) of the old pilot bushing? If it is an AX15 transmission, they had two different sizes for two different input shafts on the jeep transmissions. Measure the ID with a caliper and then measure the input shaft OD (outside diameter). See is those two pieces match up. If they don't, you can buy the correct one you need from NOVAK Jeep Conversions on the internet. Removing the bushing is pretty simple BUT BEFORE YOU INSTALL THE NEW ONE (ASSUMING THIS IS YOUR PROBLEM), "trial fit" the new bushing on the input shaft to see if it fits first. Sometimes we can't sent the wrong bushing. If you have any problems with the removal of the bushing, so a search of this website and you will find out how.

Take care,

kheihn 01-10-2012 12:30 PM

The tranny on that was on the 79 was ether a Borg-Warner or a Tremec, the 88 YJ had a Peugeot tranny. So you are most likely looking at different size.

Xpress 01-10-2012 12:44 PM

Not sure if In has smog laws or vehicle inspections as a requirement, but make sure you can do the swap beforehand.. i know in some states they won't allow you to put an engine that is older than the vehicle year (I.E. you can't put a 79 engine in an 88 frame).

Harmbl 01-10-2012 02:35 PM

OK, I put in a new pilot bushing and pre fit it to the shaft before i installed it, and even miked it after i tried to put the engine in. Still no luck. As far as the difference the BMV said it is not a problem if it is a unleaded fuel burning engine. I called the Yard just verify the swap would work ( They are the one that told me it would to begin with.) I have it in the shop now and they called me about an hour ago with the same problem.. I am really getting P.O`D and think i just might sell it and Let someone put a V8. Any other Ideas before I make my decision would be great. Thanks

Redrider94 01-10-2012 05:18 PM

Did you use a pilot alignment tool when you installed the clutch and pressure plate? If not that may be where your trouble is. Sounds like the end of the input shaft is not going into the pilot bearing.

Harmbl 01-11-2012 08:07 AM

Yes,In fact i tried two just incase the first was off a little. It feels like it goes in about an inch or so then just stops.

Redrider94 01-11-2012 09:06 AM

Did you try turning the output shaft a little to make sure the splines on the input shaft were lining up with the splines on the clutch disc?

Harmbl 01-11-2012 10:51 AM

Put a breaker bar and socket on the crank bolt and turned the engine still no luck

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