1986 Jeep Comanche AX-5, 5 Speed Transmission

[richd56]

Hi, I have a 1986 Jeep Comanche 4X4, long bed, 2.5 L, AX-5 5 Speed Tranny. I purchased this jeep in 1992 in Tn. and currently reside in Indiana. A couple of weeks ago I was driving and had to slow down then I started to here this metal grinding noise. I pulled into a Big O Tires and one of the mechanics said that he has done dealership warranty work for nothing but transmissions. He said it was the throw out bearing. I had the throw out bearing, pressure plate and clutch replaced and added new fluids as described by the hanes magazine. I am still having the grinding problems in 1st, 2nd and 3rd like before. When I shift into 4th and 5th I do not have any problem. For what it is worth, I can shift into all gears when motor is off with the clutch in or out. Does anybody have any ideas before I go looking to replace the tranny.

Thanking You In Advance

Rich

[jpnjim]

Welcome to CC. :D

 

Those tranny's are failure prone, but from the sound of it, I'd still lean towards the throwout bearing.

 

Could be the syncro's tho.

Does it do it with the engine running & T-case in neutral (assuming 4wd)?

 

What if (when driving normally) you match engine RPM's to speed (raise RPM's for a downshift, lower RPM's, but not to idle for an upshift)?

 

If a throwout isn't completely disengaging, it can do this kind of thing, but syncro's could too.

 

What does the 'tranny expert' you talked to earlier say?

[jpnjim]

Also, how does the clutch 'feel'?

 

Does it engage/disengage very close to the floor, or higher up, where it should?

 

Are you holding the pedal hard to the floor before shifting?

 

What's on your floor (no rug, OEM rug, thick pad, thick floormats, etc)?

 

Floor covering shouldn't matter much, but if you're engaging very low, it could make a difference.

 

Also, assuming hydrolic clutch fluid level is correct & bled.

[JeepcoMJ]

Hi, I have a 1986 Jeep Comanche 4X4, long bed, 2.5 L, AX-5 5 Speed Tranny. I purchased this jeep in 1992 in Tn. and currently reside in Indiana. A couple of weeks ago I was driving and had to slow down then I started to here this metal grinding noise. I pulled into a Big O Tires and one of the mechanics said that he has done dealership warranty work for nothing but transmissions. He said it was the throw out bearing. I had the throw out bearing, pressure plate and clutch replaced and added new fluids as described by the hanes magazine. I am still having the grinding problems in 1st, 2nd and 3rd like before. When I shift into 4th and 5th I do not have any problem. For what it is worth, I can shift into all gears when motor is off with the clutch in or out. Does anybody have any ideas before I go looking to replace the tranny.

Thanking You In Advance

Rich

 

 

it's not likely to be the synchros.

 

it's a bearing...either on the lay shaft or possibly on the main cluster shaft at the mid-plate.

 

 

4th works because it doesn't operate off of the lay shaft (cross shaft)...4th gear is a 1:1 ratio and it simply locks the input to the cluster gear.

 

5th gear is actually not in the main body of the transmission...it is directly behind the midplate, and does still run off of the lay shaft. but, the fact that 5th works makes me think it cannot be the lay (cross) shaft bearing at the midplate...the lay shaft is at least staying straight enough that 5th gear works. 5th gear has one of it's gears on the tail end of the cross shaft (after it goes through the midplate), and one on the output shaft.

 

 

I had a similar issue with my 86 the first time the tranny went...kind of an oscillating noise that sounded kinda like grinding. it was the front lay (cross) shaft bearing.

 

after a bearing goes bad, the entire transmission should be disassembled (removing cases is necessary just to replace the bearing BTW) and at least cleaned, so that there won't be any debris in it.

 

 

The company that replaced your clutch determined the problem INCORRECTLY and I can guarantee you that. take it back, tell them what I've told you, and tell them that they can either pay you back what you payed them for the labor on the clutch job (since the idiots didn't fix what they said they were gonna fix), or tell them you'll get your lawyer.

 

OR, if they can do transmissions, tell them to do your transmission, and then incorporate all labor from the previous (bungled) repair into this one. meaning that they would save face, and they would not have to pay out, but you'd get it fixed and not lose out on money.

[jpnjim]

 

it's not likely to be the synchros.

 

it's a bearing...either on the lay shaft or possibly on the main cluster shaft at the mid-plate.

 

 

4th works because it doesn't operate off of the lay shaft (cross shaft)...4th gear is a 1:1 ratio and it simply locks the input to the cluster gear.

 

5th gear is actually not in the main body of the transmission...it is directly behind the midplate, and does still run off of the lay shaft. but, the fact that 5th works makes me think it cannot be the lay (cross) shaft bearing at the midplate...the lay shaft is at least staying straight enough that 5th gear works. 5th gear has one of it's gears on the tail end of the cross shaft (after it goes through the midplate), and one on the output shaft.

 

 

I had a similar issue with my 86 the first time the tranny went...kind of an oscillating noise that sounded kinda like grinding. it was the front lay (cross) shaft bearing.

 

after a bearing goes bad, the entire transmission should be disassembled (removing cases is necessary just to replace the bearing BTW) and at least cleaned, so that there won't be any debris in it.

 

 

The company that replaced your clutch determined the problem INCORRECTLY and I can guarantee you that. take it back, tell them what I've told you, and tell them that they can either pay you back what you payed them for the labor on the clutch job (since the idiots didn't fix what they said they were gonna fix), or tell them you'll get your lawyer.

 

OR, if they can do transmissions, tell them to do your transmission, and then incorporate all labor from the previous (bungled) repair into this one. meaning that they would save face, and they would not have to pay out, but you'd get it fixed and not lose out on money.

 

I think I am reading this differently than you,

to me, it sounded like the issue was only during shifting.

 

I re-read it after your post, and if it's a constant noise, it would not be syncro's, or clutch (as you said).

 

Your also right, that if it is a constant noise, they should not have diagnosed TO & clutch. :nuts:

[JeepcoMJ]

I think I am reading this differently than you,

to me, it sounded like the issue was only during shifting.

 

I re-read it after your post, and if it's a constant noise, it would not be syncro's, or clutch (as you said).

 

Your also right, that if it is a constant noise, they should not have diagnosed TO & clutch. :nuts:

 

 

it wouldn't be a constant noise. only while in those gears and accelerating. perhaps at coast too, but not likely.

 

he will know soone enough...if it's that problem left unfixed, he's only got another few hundred miles on the trans, if that.

 

that's okay tho....for some reason I can't seem to get more than 700-1000 miles on an ax5 behind the 3800 :yes: :rotf: :rotfl2:

[Geonovast]

How's reverse work? If either of the layshaft bearings are going out, I would bet it either won't go into reverse, or it would make A LOT of noise.

 

You said you replaced the fluid... was there any metal shavings on the magnet on the plug?

 

Welcome to CC. :D

 

Those tranny's are failure prone, but from the sound of it, I'd still lean towards the throwout bearing.

 

 

Not really, the AX-4/5 is a very sturdy transmission for it's size, and for being considered a "light duty" trans. If the trans was failure prone, they wouldn't have used it for more than 15 years. After all, Jeep did away with the pukey after 2 1/2, and threw in the AX-5's big brother.

 

that's okay tho....for some reason I can't seem to get more than 700-1000 miles on an ax5 behind the 3800 :yes: :rotf: :rotfl2:

Gee, I can't imagine why.

[richd56]

Thank you for all of the responses. I will try and answer all the questions asked. It only makes the noise when driving vehicle in 1,2,3rd and reverse.. The clutch does not feel right, not much clutch there. The clutch disengages and engages close to the floor. I have to hold the pedal close to the floor to shift now, I didnt have to do that before. The fluid was changed and there was metal in it. When the throw out bearing, clutch etc was change it did run better for a day but the clutch felt bad, after that it started making the metal on metal noise again. I just tried the transmission with the transfer in neutral and no noise. When the transmission is in nuetral you can hear noises and when the clutch is pushed in it stops. I'm lost on what to do. If I take it in to a shop it will cost me hundreds, if I let a backyard mechanic do it most likely it will not be right. What to do?

Thanks Again for all of the replys, I will let everyone know what the problem was. Any info or suggestions will be appreciated.

Thanks

Rich

[Geonovast]

Bleed the clutch. You're lucky and have an external setup.

 

When you do though, take the slave off the bellhousing and make sure it stays completely compressed while you bleed it.

[JeepcoMJ]

Thank you for all of the responses. I will try and answer all the questions asked. It only makes the noise when driving vehicle in 1,2,3rd and reverse.. The clutch does not feel right, not much clutch there. The clutch disengages and engages close to the floor. I have to hold the pedal close to the floor to shift now, I didnt have to do that before. The fluid was changed and there was metal in it. When the throw out bearing, clutch etc was change it did run better for a day but the clutch felt bad, after that it started making the metal on metal noise again. I just tried the transmission with the transfer in neutral and no noise. When the transmission is in nuetral you can hear noises and when the clutch is pushed in it stops. I'm lost on what to do. If I take it in to a shop it will cost me hundreds, if I let a backyard mechanic do it most likely it will not be right. What to do?

Thanks Again for all of the replys, I will let everyone know what the problem was. Any info or suggestions will be appreciated.

Thanks

Rich

 

it's the front cross shaft bearing which has failed. probably has more damage than that now.

 

where are you located? I do have a 5 speed 4wd ax5 here that's in good shape.

 

 

and let me reiterate...if you took it to a shop you had do the job screwed it up. not only did they misdiagnose the problem, and fix what they misdiagnosed, but they apparently did not even do the job correctly. if your clutch got weaker, then THEY did not do it right and there is air in the system, or leaks, or failures. so...I would take it back to them and tell them you either want your money back, or you want them to fix the problem correctly at 60% below what they would normally charge. if they don't bite, you can call them out by getting the police and city (or town) involved...they can lose their mechanic's license for not doing it right.

 

did they do the fluid change? did they tell you about the shavings? if they did it, but did not tell you, then they are liable and I cannot believe they put that tranny back in after the clutch job. it should never have gone back in the truck.l

 

your best bet right now is a tranny swap.

[JeepcoMJ]

my take on this is that it's grinding constantly while in gear.

 

 

I need to ask, to be sure...is it grinding when going in to gears and/or between gears, or is it grinding constantly while driving?

[jpnjim]

After all, Jeep did away with the pukey after 2 1/2, and threw in the AX-5's big brother.

 

The Peugeot tranny was expensive, and only used to fulfill 'French Content' requirements put in place by the French government over Renault.

 

Once Chrysler took over, they no longer had to meet those requirements, and worked to phase out the French parts.

[Geonovast]

After all, Jeep did away with the pukey after 2 1/2, and threw in the AX-5's big brother.

 

The Peugeot tranny was expensive, and only used to fulfill 'French Content' requirements put in place by the French government over Renault.

 

Once Chrysler took over, they no longer had to meet those requirements, and worked to phase out the French parts.

 

Yes, but if it was a good transmission, don't you think they would have kept it? :rotf:

 

I guess my point is that the AX-5 isn't a bad trans.

[jpnjim]

Thank you for all of the responses. I will try and answer all the questions asked. It only makes the noise when driving vehicle in 1,2,3rd and reverse.. The clutch does not feel right, not much clutch there. The clutch disengages and engages close to the floor. I have to hold the pedal close to the floor to shift now, I didnt have to do that before. The fluid was changed and there was metal in it. When the throw out bearing, clutch etc was change it did run better for a day but the clutch felt bad, after that it started making the metal on metal noise again. I just tried the transmission with the transfer in neutral and no noise. When the transmission is in nuetral you can hear noises and when the clutch is pushed in it stops. I'm lost on what to do. If I take it in to a shop it will cost me hundreds, if I let a backyard mechanic do it most likely it will not be right. What to do?

Thanks Again for all of the replys, I will let everyone know what the problem was. Any info or suggestions will be appreciated.

Thanks

Rich

 

Easiest guess would be the tranny is bad, but I'm confused that the noises went away for a day after the swap.

Might have been the new fluid, and getting rid of the metal filled old oil. If the shop did the oil change, they should've known you have serious damage, and driving it like that will only make it worse.

 

Safest bet would be to drain the oil again, and look at it.

If there was shavings in it before, and you didn't fix anything internal, they're probably back again.

 

Are the noises worse now than they were before you did the work?

 

Is it possible they used the wrong lube?

As far as the clutch, it sounds like something isn't tight, and letting air into the system.

Is the res still full?

 

Look at the oil, if there's metal in there again, already, start thinking about a replacement.

[jpnjim]

After all, Jeep did away with the pukey after 2 1/2, and threw in the AX-5's big brother.

 

The Peugeot tranny was expensive, and only used to fulfill 'French Content' requirements put in place by the French government over Renault.

 

Once Chrysler took over, they no longer had to meet those requirements, and worked to phase out the French parts.

 

Yes, but if it was a good transmission, don't you think they would have kept it? :rotf:

 

I guess my point is that the AX-5 isn't a bad trans.

 

I think the Peugeot gets a bad rap.

I replaced one bad one @250k miles, and had 3 others that held up fine.

I really doubt an AX-5 would hold up as well behind a 4.0L.

Using it only behind the 2.5L gives the false sence of it being stronger than it is.

Even still, plenty of people break them with 2.5L's, and that's saying alot.

They went to the extra effort & cost of using AX-15's in 2.5L Dakota's for a reason.

[Pete M]

The Peugeot gets its bad rap because it was put behind an engine it was barely rated for. Maybe it'd last forever behind a 2.5L. :dunno:

[JeepcoMJ]

 

I think the Peugeot gets a bad rap.

I replaced one bad one @250k miles, and had 3 others that held up fine.

I really doubt an AX-5 would hold up as well behind a 4.0L.

Using it only behind the 2.5L gives the false sence of it being stronger than it is.

Even still, plenty of people break them with 2.5L's, and that's saying alot.

They went to the extra effort & cost of using AX-15's in 2.5L Dakota's for a reason.

 

hey man, if I can get a bad rap for being a piece of sh*t, then so can the pukegoat.

 

I've not once seen one that didn't have issues after it was even mildly abused.

 

as for an ax5 behind a 4.0....it's NOT possible. there's no bellhousing for it.

 

that all said, I transplanted a buick 3800 from a 1996 camaro into my 1986 longbed comanche. it's a 60 degree gm bellhousing with a 90 degree block, and more or less bolted to the transmission (custom clutch @$$'y and modified bellhousing for starter).

 

I abused that motor ALOT. beat a 2 cylinder rotary RX7 with it hands down lol. the 3800 outputs more hp and more torque than a 4.0 liter while being more efficient, in stock form. mine is bored over .030 with competition cams, outputting 263hp and around 230ftlb torque, and it EATS ax5's like nothing. as I've said, I can't get more than 1K miles on an ax5 with it.

 

hence I have an ax15 and dakota bellhousing. unfortunately something got in the number 3 bearing on the motor, so I have it out and am rebuilding it now.

[jpnjim]

The Peugeot gets its bad rap because it was put behind an engine it was barely rated for. Maybe it'd last forever behind a 2.5L. :dunno:

I agree.

I've also had more good luck, than bad with them.

 

At one point, when worn, nearly junk BA10-5's were selling for $1000+ each, I'd bring a spare when wheeling out of state,

but I never needed it.

 

When the 250k one failed in my 87', it made a ton of noise first, and gave me plenty of notice it was crapping out.

That was before I knew you could convert 2wd BA's to 4wd, so I nursed it along for months, till I could buy a whole YJ, just for the tranny. (still less than $1k tho).

[JeepcoMJ]

The Peugeot gets its bad rap because it was put behind an engine it was barely rated for. Maybe it'd last forever behind a 2.5L. :dunno:

I agree.

I've also had more good luck, than bad with them.

 

At one point, when worn, nearly junk BA10-5's were selling for $1000+ each, I'd bring a spare when wheeling out of state,

but I never needed it.

 

When the 250k one failed in my 87', it made a ton of noise first, and gave me plenty of notice it was crapping out.

That was before I knew you could convert 2wd BA's to 4wd, so I nursed it along for months, till I could buy a whole YJ, just for the tranny. (still less than $1k tho).

 

we're off-topic. but don't you have to swap the output shaft, and output housing in order to convert it from 2wd to 4wd?

 

that's how I've done several of my ax5's, since the outputs/tail housings are not the same.

[jpnjim]

 

I think the Peugeot gets a bad rap.

I replaced one bad one @250k miles, and had 3 others that held up fine.

I really doubt an AX-5 would hold up as well behind a 4.0L.

Using it only behind the 2.5L gives the false sence of it being stronger than it is.

Even still, plenty of people break them with 2.5L's, and that's saying alot.

They went to the extra effort & cost of using AX-15's in 2.5L Dakota's for a reason.

 

hey man, if I can get a bad rap for being a piece of sh*t, then so can the pukegoat.

 

I've not once seen one that didn't have issues after it was even mildly abused.

 

as for an ax5 behind a 4.0....it's NOT possible. there's no bellhousing for it.

 

that all said, I transplanted a buick 3800 from a 1996 camaro into my 1986 longbed comanche. it's a 60 degree gm bellhousing with a 90 degree block, and more or less bolted to the transmission (custom clutch @$$'y and modified bellhousing for starter).

 

I abused that motor ALOT. beat a 2 cylinder rotary RX7 with it hands down lol. the 3800 outputs more hp and more torque than a 4.0 liter while being more efficient, in stock form. mine is bored over .030 with competition cams, outputting 263hp and around 230ftlb torque, and it EATS ax5's like nothing. as I've said, I can't get more than 1K miles on an ax5 with it.

 

hence I have an ax15 and dakota bellhousing. unfortunately something got in the number 3 bearing on the motor, so I have it out and am rebuilding it now.

 

Wow, I didn't want to polute this guys thread with this stuff, but here goes:

 

I know an AX-5 won't bolt to a 4.0L.

I also know they could've easily built a bellhousing to fit, if they thought it would hold up.

The fact that they didn't, and designed an AMC to AX15 bell instead should say something about what they thought an AX5 could handle.

 

If the cheaper AX5 could hold up, why go to the 15?

 

As far as Peugeot abuse,

I ran converted 88/89 2wd Peugeots, that had the taller 3.76 1st gear.

It's not much difference, but the 2 blown up ones I dissected both had deeper 4.00:1 first gears. (all things being the same, deeper gears = weaker).

 

I also ran 85w90 gear oil, instead of 10w40.

 

Like I said above, I would sometimes bring a spare with me, so I wasn't holding back on them, and I never had one fail off road.

 

I've broken plenty of other stuff, but the Peugeot's held up.

[jpnjim]

 

we're off-topic. but don't you have to swap the output shaft, and output housing in order to convert it from 2wd to 4wd?

 

that's how I've done several of my ax5's, since the outputs/tail housings are not the same.

 

The output shaft of BA's is splined all the way through the tailhousing, till it gets to the output bearing.

The speedogear is then internally splined to slide all the way down the output shaft.

 

Clean the shavings out of a blown up 4x4 Peugeot's rear housing, bolt it in place of the 2wd's tailhousing, and trim the output shaft to fit.

Get a 21spline 231, and you're good to go.

 

I did my first 2x4 to 4x4 MJ swap without even pulling the tranny.

 

No one told me you could do it, I had the 4x4 rear output, and some time to check it out.

[richd56]

JeepCoMJ, it is grinding when I start to take off and continues until I get into 4th gear. I have not drove far with this tranny since the new throw out bearing and clutch was installed, maybe 100 miles max. The last time I drove it the noise was really loud when I started to take off, so I was taking off in 4th and keep it in 4th all the way home.

I live in southern Indiana, could you send me a private message on the cost of the tranny and what your thoughts our at this point.

Thanks

Rich

[JeepcoMJ]

JeepCoMJ, it is grinding when I start to take off and continues until I get into 4th gear. I have not drove far with this tranny since the new throw out bearing and clutch was installed, maybe 100 miles max. The last time I drove it the noise was really loud when I started to take off, so I was taking off in 4th and keep it in 4th all the way home.

I live in southern Indiana, could you send me a private message on the cost of the tranny and what your thoughts our at this point.

Thanks

Rich

 

 

okay. just to clarify...it's grinding after you put it in gear, in all gears up to 4th gear?

 

 

or it's grinding when you are in the process of putting it in gear?

[Eagle]

I'm entering this discussion a bit late, but I think JeepcoMJ has it pretty well doagnosed. Just to add a point nobody seems to have yet clarified -- when the throwout (release) bearing is bad, it makes noise ONLY when your foot is on the clutch pedal and the clutch is disengaged. That's because this is the only time the throwout bearing is doing anything -- the rest of the time it's just sitting there.

 

If the tranny is making noises when the vehicle is moving and your foot isn't on the clutch -- it ain't the throwout bearing.