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Another Ax-15 Question


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As most of you know I converted Bucky from 2 to 4X4. before the paint mess...

Driveline parts for the sake of the question are:

original 4.0 renix engine (pushing 300k miles, go team). New AX-15 trans, with external slave cylinder, New NP 231, 4-56 gears in (non disco)D30 front D44 rear, Advanced adapted cable shift set up for transfer case. Luk HD clutch.

 

Since Day one on the street following the conversion the transmission has been exceptionally stiff shifting(for the record it is presently filled with 10-30 synthetic). All along I have written this off to new internals syncros etc. etc.

I have possibly 4 to 5 thousand mostly street miles on the truck at this point since the conversion, and my thoughts that the trans would "loosen up a bit" have not happened. 1st to 2nd is real tight, 2nd to 3rd a bit better 3rd to 4th and 4th to 5th no problem. and as expected a slight double clutch to get into reverse, no biggie. The issue and question is downshifting...Any down shifts are significantly worse (harder) with 3rd to 2nd virtually impossible. I would hate to be on a tight inclined trail and need to down shift 3rd to 2nd...serious pucker factor I'm sure.

 

Some time back before the paint fiasco...After trying to get the console over the shifter in the interior, I came to the conclusion that I have a wrangler shifter presently in the truck, in other words the XJ console won't fit. I scored an XJ specific AX15 shifter a while back and the other night pulled it out of the shed. Right after I had originally acquired it I pulled the wrangler one out and was going to swap them.

After I got the wrangler one out I noticed that the diameter of the plastic (doughnut/ball/bushing call what you want) on the internal end of the shifter is different between the two. With the presently installed being bigger in diameter by about .080". At the time I just noticed the difference and felt I should double check before slapping the (sloppier) one in. What is anyone's opinion as to whether the reduced diameter (plastic piece) will loosen up the shifting or have any impact whatsoever? I had forgotten about the difference in diameter till I pulled it out the other night and though hell maybe it will help...Is there anything else that I should look at? I will when weather permits open it back up and try it regardless (and change the fluid to Redline MT90 at the same time)I am just curious if anyone else has suggestions/opinions.

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Does it physically feel stiff at the shifter or does it feel stiff inside the trans?

 

 

I have been through 4 clutch masters, I think I fixed it this time. From my experience if the master/slave is not working perfectly, not having enough throw to FULLY disengage the clutch, it does make it more difficult to shift.

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the problem definitely seems at the shifter rather than internal. But both of your suggestions seem more than plausible.

I would note that the clutch master /slave was a pre-bled complete Mopar assy. that was brand new. does that lesson this as a potential reason?

It is cold wet and snowing out where the truck is, or I would already be trying the XJ shifter....I really thing this is at least part of the problem.

I was unaware that there were two different shift towers also. And knowing that makes me think that the solution may be as simple as the swap of shifters.

If I get bored enough I may go out and piddle with it this afternoon despite the weather. Many thanks for the suggestions.

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So does anyone know if there is a difference in HIEGHT of the TJ/YJ shift tower vs the Cherokee shift tower for the AX-15?

and If the height is different does it effect how far into the trans the shifter goes? as I only have the one that is on the trans (and unsure which it is) I have nothing for comparison. Hopefully thw weather will warm up enough to do some tinkering in the next couple of days.

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I tried just changing the shifters yesterday and the one that was reputed to be from a cherokee. is clearly shorter (on the end inside the trans.) enough so as to not engage the shift guide(saddle whatever it is actually called). That it is not possible to get into 2nd gear at all. I am starting to think that the shifter I got with the transmission is actually for a Dakota. and taht is why there are so many differences in it. Here are some pictures. The shifter with the Momo wood knob is the one I got with the trans and have been using since the conversion. The top portion of it that threads onto the silver shift arm is the top of the shifter from the peugot original I cut off and used. the other shifter in the photo is the XJ (or so I was told) unit.

 

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I also checked the shift tower hieight that is on the trans in the truck as best I could without removing it. It would apear that the hieght from the mount surface to the top without the shfter or boot is 2.50". Soooo if the hieght of the shift tower on an AX-15 for an XJ or MJ is 2.00" (ish) I think I have found my answer. Can anyone confirm the shift tower hieght for a known XJ/MJ unit before I go to the junkyard?

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Nope. Off that '84 XJ I got for the diesel conversion. You should see some of the other Mickey Mouse crap this guy came up with. The exhaust hook up for the turbo looks like something a drunk plumbers apprentice might have come up with. In his worst nightmare.

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Screw It.... I just ordered the Hurst unit.

http://i.ebayimg.com/t/Core-Hurst-shifter-1989-1999-Jeep-Cherokee-Comanche-6-cyl-w-AX15-5-speed-/00/s/NjAwWDUxNg==/z/5YwAAOxy3zNSpLA4/$_3.JPG

Review will be posted following arrival and installation.

Need to move on to other stuff. The exhaust leak from the pacesetter header is driving me nuts

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  • 2 months later...

Screw It.... I just ordered the Hurst unit.http://i.ebayimg.com/t/Core-Hurst-shifter-1989-1999-Jeep-Cherokee-Comanche-6-cyl-w-AX15-5-speed-/00/s/NjAwWDUxNg==/z/5YwAAOxy3zNSpLA4/$_3.JPGReview will be posted following arrival and installation.Need to move on to other stuff. The exhaust leak from the pacesetter header is driving me nuts

Actual link to shifter? How did it work out?

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This is the company that builds the Hurst shifters.  You can buy from the site or through one of their e-bay sales.  http://www.core-shifters.com/servlet/the-822/Core--fdsh--Hurst-shifter/Detail
I am currently running one on my 88 Pioneer, and While I can't say for sure if it will help with how tight the shifting is (I never had a factory shifter on mine) I will say that the shorter throw is really nice - especially compared to my old BA-10- and the shift knob ended up in a very comfortable spot for me (6'5" of me) while driving.  The throws are still decent in distance, so mistakenly grabbing the wrong gear hasn't been a problem for me, although admittedly I am used to cars with very small gate patterns which might affect how I perceive it compared to you.

 

To the OP.  I am actually running the same thing and going through a similar problem.  I have about 3000 miles on my external AX-15 conversion, The trans is a fully rebuilt unit with new SACHS clutch and a SACHS pre-bled master and slave setup. (Yea, I like my German stuff lol). I am running regular ol' Mobil Synethetic 10w-30 in the transmission, and my shift gates were pretty tight at first too.  AFAIKT I am getting full clutch release, but I did notice that the first 500 miles I had the same problem that you did with getting into gears, even on upshifts.  Now, aside from an occasional hiccup from 1-2, it's been shifting fine, although the gates are still tight and the shifts are very notchy feeling.   At this point I am thinking to drain the mobil out and run Redline MT-90 instead, because the way this trans feels tells me that the oil just isn't "sticky" enough because it lacks the additive package of a gear oil, even if the working viscosity of 75-90 is the same as 10-40 it does seem to make a big difference.  I've had a couple of toyota transmissions in the past that felt the same way, and it got much better using Redline MT-90.

 

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