I just bought this 87 Cherokee 4.0L

I honestly don't know what tranny is in there but I assume it is stock. The problem is that it won't shift until it sounds like the engine is gonna blow up. I don't have a tach but I would geuss about 4000-4500 RPM's.?

I was told that it could be a bad filter but that doesn't make sense to me. I have also been told it could be the Throttle Control Sensor because it is sending the tranny a bad signal.

Do either of those make sense and what other options could it be.

The tranny is stock with about 200,000 mi so it could be going out but I want to check everything else before I go grab a new tranny. The fluid looks good and is the right level.

Thanks

 

try adjusting your tv cable!

 

http://www.naxja.org/forum/showthread.php?t=1015963

 

Before you rush out and do a flush, drop the pan change the filter and fill it back up accordingly. Don't take all the fluid out, it will shock the tranny and shorten it's life by 100%

 

Make sure that trans cable is adjusted proper, and wouldnt hurt to change the TPS. I wouldnt tear into the transmission just yet if you dont have to

 

Adjust the TV cable, see if it helps.
After that I would look at the TPS.
Then do a drain/fill (NOT a flush, just pull drain plug and refill.)

 

did you check the fluid while it was runnin

 

I agree with this strategy.

The throttle position sensor is DIRECTLY involved with transmission shifting characteristics. On an 87, they are also ADJUSTABLE, and proper adjustment is important.

If fluid level and condition checks out, test and adjust your TPS. If it fails either of these procedures, replace it.

 

im having the same problem with an 87 have changed the tps and it seems fixed then back to same if i pull the fuse to the trans computer the trans shifts manually im sure the tps was bad but after replacing it the problem is more intermint like a bad power supply or ground??? when it workes it workes fine then out of the nowhere its back have even thought of hooking a volt gadge to the tps so i can see if im loosing power.

 

Alright! Thanks for the info. I'll start looking at the TV cable and TPS after I get off of work tonight.

Someone told me it could be the torque converter. I honestly can't remember how that part affects everything else. Could that be something to test if it isn't the TPS or TV cable?

 

Does NOT sound like a torque converter issue.

Verify TV cable adjustment and complete and thorough operation and adjustment of your throttle position sensor.

I think you'll find the answer in one of the above.

 

TPS was bad. I tested it and the readings were all messed up so I replaced it. Works almost perfect now. I still need to adjust it but atleast is shifts! Thanks for all the advice.

I should know this but I can't remember what the TV cable is. It's been so long since I had a car that I worked on. I never touched it cause I didn't know what it was. Anyone care to explain?

 

Thanks all you jeep peeps now my 88 jeep cherokee is on the road and doing good the tps went out and had me stumped for a bit and then i came acrost you all and wow thanks again . Travis

 

No need to drop the pan. Just drain it and refill with 3.8 quarts of Dex/Merc fluid.

It very well could be the throttle position sensor or bad grounds. Do all the things below before wasting another minute on other stuff.

The Renix era XJs and MJs were built with an under-engineered grounding system for the engine/transmission electronics. One problem in particular involves the multiple ground connection at the engine dipstick tube stud. A poor ground here can cause a multitude of driveabililty issues, wasted time, failed emission tests, and wasted money replacing components unnecessarily.

All the components listed below ground at the dipstick tube stud:

Distributor Sync Sensor, TCU main ground, TCU “Shift Point Logic”, Ignition Control Module, Fuel Injectors, ECU main ground (which other engine sensors ground through, including the Oxygen sensor, Knock Sensor, Cruise Control and Transmission Sync signal. All extremely important stuff.

The factory was aware of the issues with this ground point and addressed it by suggesting the following:

• Remove the nut holding the wire terminals to the stud. Verify that the stud is indeed tightened securely into the block. If the whole stud turns, you can use a 7/32″ six point socket or wrench to hold it so the nut can be removed. Worst case, cut the wires and remove the stud and nut. Install new terminal eyelets on the wires when going back together. Scrape any and all paint from the stud’s mounting surface where the wires will attach. Surfaces must be clean, shiny and free of any oil, grease, or paint.
• Inspect the wire terminals. Check to see that none of the terminals are crimped over wire insulation instead of bare wire. Be sure the crimps are tight. It wouldn’t hurt to re-crimp them just as a matter of course. Sand and polish the wire terminals until clean and shiny on both sides. Apply a liberal coating of OxGard, which is available at Lowe’s and other stores. Reinstall all the wires to the stud and tighten the nut down securely.

While you’re in that general area, locate the battery negative cable which is fastened to the engine block just forward of the dipstick stud. Remove the bolt, scrape the block to bare metal, clean and polish the cable terminal, apply OxGard, and reattach securely.

Another area where the grounding system on Renix era Jeeps was lacking is the engine to chassis ground. There is a braided cable from the back of the cylinder head that also attaches to the driver’s side of the firewall. This cable is undersized for its intended use and subject to corrosion and poor connections at each end.

• Remove the cable end from the firewall using a 15mm wrench or socket. Scrape the paint off down to bare metal and clean the wire terminal. Apply OxGard. Reattach securely.
• Remove the other end of the cable from the rear of the head using a 3’4″ socket. Clean all the oil, paint and crud from the stud. Clean the wire terminal of the cable and reattach securely with a liberal coating of OxGard.

2 STRONG suggestions regarding the ground system:

I prefer to add a #4 gauge cable from the firewall to a bolt on the rear of the intake manifold, either to a heat shield bolt or fuel rail bolt. A cable about 18″ long with a 3/8″ lug on each end works great and you can get one at any parts store already made up. NAPA has them as part number 781116.

A further improvement to the grounding system can be made using a #4 cable, about 10″ long with 3/8″ terminals at each end. Attach one end of this cable to the negative battery bolt and the other end under the closest 10mm headed bolt on the radiator support just forward of the battery. NAPA part number 781115.

For those of us with Comanches, it’s very important to remove the driver’s side tail lamp assembly to access the ground for the fuel pump. Remove the screw holding the black ground wire. Scrape the paint from the body and corrosion from the wire terminal. Add a 10 gauge wire, with an eyelet on each end, from that grounding point to a bolt on the frame. Better yet, on both Cherokees and Comanches, complete Tip 29 for the best fuel pump grounding. Be sure to scrape all mounting points to bare metal and apply OxGard also.

If you want to upgrade your ground and battery cables with custom made parts, contact Neal at www.meanlemons.com



Revised 02/04/2017