Comanche Quickly Downspiraled One Day.

[phathank]

Aw4 trans, 2wd started acting funny, wouldn't go above 35. Then all the sudden it lost everything and wouldn't hit any gears but in and out of park. It it did was make a spinning sound around the front if the trans maybe, like the sound a tire makes if it rubs against a wheel well. Check the TCU, it seems fine. Plus this really feels like more of a mechanical issue. This isn't something to do with the torque converter behind my driveplate, could it? Anyone know the issue?

[Strokermjcomanche]

Could be the trans pump or torque converter . I would also check to see that the flexplate to converter bolts are tight and not missing . Maybe check the bell housing bolts as well

[phathank]

Got a good torque converter today. All the bolts are tight and the fluid seemed to be circulating well. Nothing was overheating I believe.

[dasbulliwagen]

You need to pull it apart to check everything, sounds like it could be a broken flexplate. Will the engine fire back up or does the starter just spin? If it won't crank over, but the starter spins, it could be a bad flexplate, that would be good for you as its an easy fix. Good luck, let us know what you find.

[phathank]

Flexplate checks out fine. It is amazingly clean too. No cracks or any discrepancies whatsoever. I really hope it is the torque converter. Honestley the radiator failed a while back, but I cleaned the hell out of the trans and engine from that. I hope that instance didn't condemn the whole thing. Gonna pull it apart and replace the torque converter, change the filter. Will let you know if it helps.

[gogmorgo]

As long as you didn't completely cook the engine, (sounds like it still runs) the rad failing shouldn't have done too much... unless it failed in a way that got coolant in the tranny lines.

 

When you take the tranny off and have good access, check your flexplate really close for cracks, just in case. No sense doing the work only to have to redo it. I recently replaced mine. Through the inspection plate, initially all I saw to tell me that it was bad was a hairline crack really close to the crankshaft flange that I honestly wasn't sure was actually a crack. Six months later, when I finally replaced it, the truck still started great, ran (like $#!& due to the cps timing windows being +/- 10 degrees) and drove, but it was cracked all the way around into two separate pieces.

After everything's back together, I'm thinking the cracked flexplate (and the engine-tranny separation that cracked it) may have also trashed my torque converter, as I have a slight grinding noise when I'm holding it in gear on the brakes, but only then. That'll have to be a spring project for me, though.

[phathank]

I know what you mean. I just replaced a flexplate in a Cherokee I bought for a donor to my Comanche with the same aw4. The flexplate looked fine till I took it out and wire brushed it. I then saw a crack all the way around the center. The funny thing is, the only thing holding the tranny to the engine was the rear mount on the crossmember. All four bolts from the tranny to the engine were missing. The sag caused the flexplate to groove into the starter. Luckily that was the only damaged caused. When I drop the tranny on the Comanche, I will have to take the flexplate out to replace the torque converter anyway. Then I will get a better look at it. Can't wait till spring, having withdrawals already.

[phathank]

By the way, coolant did get into the tranny lines, but I noticed a smell and turn the Comanche off right away. Had it towed home and spent a whole winter cleaning it out. I hope this isn't the result of any damage I didn't notice.

[gogmorgo]

I honestly don't really know what coolant in the lines could do to the tranny, but having caught it sooner rather than later I'd imagine you'd be okay. But I'm far from an expert. I'd also be concerned about air getting in.

 

I'm confused as to why you'd need to take the flexplate off to replace your torque converter. Having just recently replaced my own flexplate, I'm not sure how you'd even be able to remove the flexplate without first unbolting the torque converter from it. The first thing you do when pulling the transmission (as you should know from your Cherokee) is unbolting the flexplate and torque converter. Then you can unbolt the tranny &c and move it back out of the way. The torque converter stays with the tranny, and the flexplate is still bolted to the crankshaft. I'm not sure how you'd even be able to get at the bolts that hold the flexplate onto the crank seeing as they'd be under the torque converter if it was still there... It would be a bit like trying to get your brake rotors off without first taking off the wheel...   :???:

 

My tranny was still hanging on by about three threads on one of the upper bolts, and the tranny mount. Also, one of my motor mounts was destroyed (completely) and the other was on it's way out.... and yet the truck still drove me 70 miles at 80mph several hours before I discovered I had a fairly major issue... 80 mph with the engine and tranny just kinda, well, sitting there... I'd just driven into a city because I'd diagnosed the issues the truck had running as an intermittent fuel pump and was about to pick up a new one.

[phathank]

You are right. That's what I mean. When I slide the trans back, I will get a better look at the flexplate.

[phathank]

The comanche lives, better than ever. Makes my Cherokee lame. So far I suspect it was the torque converter. The different one is responding well and after I leveled out the tranny fluid and drove around, it's like nothing ever happened. Tears in my eyes over here.