View Full Version : 86 Turbo 4x4 auto trans issue

10-04-2011, 05:30 AM
I'm going to preface this by telling you that I don't know much about automatic transmissions. I've mostly owned manuals.

About 2 weeks ago, my torque converter on my transmission stopped locking into overdrive. Normally at 60, the engine would run about 2,000 rpm and now all of a sudden it runs 2,200-2,500 to maintain speed. I got the truck home and changed the fluid. I put in some fresh Valvoline Dex/Merc and a bottle of Lucas oil transmission no slip. Truck seems to be working fine. Locks into overdrive.

Again tonight, the converter will not lock up in OD. The first time this happened was on the same route I drove tonight, which is all highway and slightly uphill.

Possibly related, but not sure, is that when the transmission shifts from 2nd to 3rd, it's not smooth and the tach dips suddenly and then goes back up to "normal" RPM.

The transmission has 268k miles on it and as far as I know has never been rebuilt. I've owned the truck for a year and put only 8k miles on it in that time.

Any thoughts would be appreciated.

It seems difficult to find parts for this transmission (such as solenoids). I'm thinking a rebuild is what is going to be needed but know that is going to run into some serious money. I would love (LOVE) to do a manual swap, but do not think I am ready to take on such a task.

10-05-2011, 01:05 AM
check the coolant temp sensor on the engine - if the ECU doesn't see normal operating temp it may prevent it from going into overdrive, could also affect shift feel if it thinks the trans fluid is still cold (not sure if it had a separate trans temp sensor)

FWIW, try to find out what the transmission model is. I can't remember which years or what trans model, but at one point Jeep used a Toy a/t which would make parts and upgrades much more available if there's a good interchange

10-05-2011, 01:40 AM
It's an A340E and thank you for your advice.

10-05-2011, 03:39 AM
check this link out: http://www.pirate4x4.com/forum/showthread.php?t=587521

10-05-2011, 05:00 AM
Thanks for those links.

After doing some more reading, I'm finding that I can replace all 3 solenoids for about $200. I'm also reading that my transmission is prone to overheating because of the hydraulic transfer case mated to it which can cause the converter to not lock up. It looks like I can add an external cooler for about $50. Add a transmission filter change and for about $300 I could potentially have a nicely working transmission.


10-06-2011, 01:51 AM
Hmmm, I can't really add much more - the technician in me would want to diag before advising on replacing any parts. Maybe just one other thing to check would be your TPS, which the computer is going to use to help determine shift points. In the past there might have been a "kick down cable" or "vacuum kick down solenoid" but with electronic control the ECU uses TPS, VAFM, etc. to determine engine load which obviously affects trans operation. Just make sure the engine is in good operating condition and state of tune before you condemn the transmission.

10-06-2011, 04:50 AM
I really think you should just bite the bullet and go manual swap

10-12-2011, 12:05 AM
I think I am going to "bite the bullet" and do the trans swap. A local shop, Yota Masters for those in So Cal, quoted me $1500 for a complete W56 trans/t-case swap. That includes all parts and labor. Sounded like a good price to me.

10-16-2011, 06:54 AM
Nice! I'm betting you will be much happier in the long run

10-18-2011, 05:53 AM
Okay, I call BS. I have yet yo find a turbo automatic transmission for under $700. At that, they only made these things for 2 years which means they all will have a lot of miles on them. Why buy another used, high mileage automatic that will fail (as they all will) with an unknown service history? Show me someone who will rebuild one with QUALITY parts for under $1500.

Besides, the automatic sucks the life out of this truck. Swapping a manual in will be the best thing I could do for the truck. W56 with 4.30 gears and 31's will make a nice exploring truck.

10-19-2011, 02:13 AM
Bite the bullet and transfer the '86 to a stick shift. I had the same truck 6 years ago and was facing the same problem. I had the transmission rebuilt by a local guru, new clutch packs, solenoids, everything blueprinted. Cost me $1,600 in parts and labor for me to drop it off and re-install it myself. A week later the truck ate the transmission because of a clogged cooling line and I threw in a "good" used transmission and sold the the truck three months later.

They are cool, rare little trucks if you are going to keep it swap the transmission. The rack crawling guys love those manual transmissions so parts will be available for a while.

Good Luck!

11-08-2011, 02:17 AM
Placed my deposit and the parts will be ordered. Should hopefully have the truck in the shop and the swap finished in the next couple of weeks. Looking forward to having a "new" truck!:wings:

01-27-2012, 02:18 AM
Did you get this done yet?

01-27-2012, 02:11 PM
No. Long story short, the shop took my deposit and did nothing for 4 weeks. Didn't get a single part for it. Never called, I always had to call to see what was up. I got my money back and have decided to just run the auto until it dies. Now if I could find another shop that would do it for the same price I was quoted before ($1500 including parts) I would most likely still do it.

I also think that since changing the fluid, it is shifting better and doesn't seem to be slipping. The next time I change it, I'm going to get it flushed and put a new filter in and hopefully it will be good to go for awhile.

02-18-2012, 06:09 AM
hey i bought an 86 4x4 DLX auto with the ECT i was having serious issues with the trans staying in gear it seemed confused half the time well i sent it to a trans shop they put a new valve body in it a couple of solenoids filter and fluid i had the tps replaced and adjusted and it runs like a top. i love it i would never go to a manual it's just to comfortable to drive around plus th ect with the normal and power switch really makes it nice. well good luck i hope i helped you

02-19-2012, 12:47 AM
it could be as simple as a sticking t stat. even tho the temp gauge may look like its at operating temp it may not. happen to me. i would get overdrive sometimes. ended up being a sticking t stat causing over cooling just enough for the overdrive not to work at times. overdrive wont work unless its at true operating temp.