I am finally getting back to my trans rebuild. My problem is the main shaft and counter shaft bearings that mount in the mid plate (the ones with snap rings) are not as tight of a fit as I would have expected. It's not that they are loose but I can turn the outer race by hand without a ton of effort. The bore in the plate has a small amount of discoloring but does not appear to have spun the bearings. I wanted to see what you all thought of this and I suppose I will have to get my old ones out of the scrap bin and see how their fit was as well.
AX15 Main Shaft Bearing Rotates in Bore
Posted 26 March 2014 - 09:45 PM
Not a comforting discovery, it's worth comparing the original bearing fit in that bore. If the bearing bore is round and not scarfed from bearing creep or spinning, there is a solution. Loctite makes 640 Sleeve Retaining Compound. This product really works when applied correctly. Here are the PDF details about Loctite 640, its uses and proper application:
Transmission bores that support bearings, like the AX15 intermediate plate, can lose a slight amount of tolerance over time. This intermediate plate is alloy, even more vulnerable than iron...Actual bearing creep or full-on "spinning" is not common on the AX15 transmissions and would quickly ruin the alloy plate. (The most likely causes of bearing creep or spin are excess loading or lack of lubrication.) The main shaft and countershaft bearings, though snug in their plate bores, are not an actual "press fit" into the intermediate plate. See my assembly of the AX15, steps 134-139 at:
Take into account that caged input shaft bearings are typically a finger press fit into the case bore of iron and alloy transmissions. Once in service, the bearing's outer race doesn't "spin" in the bore. Radial loads from the shaft encourage the caged balls to roll within the bearing...When I think of "spinning a bearing", the main bearings on an alloy air-cooled VW engine (with a split crankcase) come to mind. Loctite Red (271), originally called "Stud and Bearing Mount", targeted this engine's design flaw.
Sounds like you do need some insurance here. Loctite 640 could be just what you want...If you find that the original bearing outer races also rotate with light hand force in the plate bores, Loctite 640 would be a sensible safeguard.
This product is used commonly in industry on expensive machinery applications. Loctite recommends the use of its activator with the 640, and you need a clean bore and bearing outer surface for proper application. Apply 640 evenly, just a film. Install the bearings promptly, before the activated compound starts to cure. Loctite 640 is anaerobic and will cure with the parts in place.
Loctite 640 will readily take up minute "clearance" between the outer surfaces of the bearings and the plate bores. Wipe off excess compound that squeezes out during fit up. Do not allow liquid compound to drip inside the bearings or other parts!
From what you describe, Loctite 640 is the cost-effective fix for peace of mind...
Posted 31 March 2014 - 05:52 PM
Moses, your detailed knowledge of this trans is unbelievable! The Loctite 640 solution was just that, a solution. I was able to get the trans back together this evening. Next day off I am going to break down the transfer case and throw some new bearings in it, marry the two and reinstall in the jeep. Sounds easy enough, but because this TJ was abused by its previous owner (no maintenance) I'm sure to find some additional wear in there too. Thanks for your advice.
Posted 07 April 2014 - 06:11 PM
Well, I just finished installing my tranny and transfer case, after rebuilding both......and both perform better than ever! I obviously had a few stalls along the way but should be good for a long time to come. Thank you for the support on this project. Now I can move forward on getting my fuel injected 350 with full manual reverse pattern valve body TH350 into my 80' J10 rock rig.
Posted 08 April 2014 - 06:44 PM
Congratulations, TTippetts! Great job there...The J10 sounds intriguing, likely you passed on an AMC 401 or 360 V-8 buildup for cost reasons. The AMC engines have become very spendy to rebuild! The small-block 350 Chevy V-8 has been a logical mainstay, and a TH350 should work well, too. Did you consider a later LS engine? Cost should be coming down on recycled GM truck engines.
Keep us posted. Pleased that your AX15 is back together and performing as new!
Posted 11 April 2014 - 05:04 AM
Moses, the J10 project has been on the back burner for some time now (years). I have already rebuilt a TBI 350 from an old Caprice cop car, so it has the factory roller lifters. The engine/tranny have been done for a long time so once a month or so I start it up with a electric fuel pump and boat gas tank. At the time when I acquired the Caprice I had my blinders on and didn't explore the LS market, I wish I would have because I could have gotten a low mileage pull out 5.3L for what I spent on my TBI motor. I used to have a healthy 258 in the J10 but people liked the way it ran so much that I had an offer I could not refuse and sold the engine and TF727 it was mated to.
On topic the AX15/231J combo is performing great. I drove it to and from work this week. I put about 300 miles on it and all is well.
Posted 11 April 2014 - 09:58 AM
Yeah on the AX15 rebuild, great job, TTippetts!
Understand the Jeep J10 dynamic and why the TBI 350 V-8. Though less horsepower than an LS, these engines produce excellent torque, which you probably want anyway...Many GM Suburban 4x4s with the 350 TBI lugged larger travel trailers with the right axle gearing.
We had an '87 K2500 (cargo doors and 4WD, Federal emissions) and really valued that rig and its THM400 behind the TBI 350 V-8. Last heard, the truck has clocked over 300K miles on the Mr. Goodwrench crate engine installed before we bought the Suburban at 140K miles. Original owner had used Mobil 1. I kept the engine on Mobil 1, and it's still running on Mobil 1 for the friend that bought the truck at 180K miles!
Please keep us posted on the J10 project and developments, that section at the forums could use your input and findings!
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