Hello, I'm in a bit of an interesting yet frustrating situation.

Jeep TJ, 5.3L v8, 4l60e trans, to np241c transfer case.

I started the jeep after getting the exhaust completed. I noticed if I put it in drive, it didn't move and only revved. HOWEVER, if I put it in reverse, no problem, will move. Then, if I put the gas pedal down enough, it would move! Jeep had been sitting a while, so I figured the brakes were a little rusty and needed some extra umph to get going.

I got going on the road and it wouldn't shift out of first gear. So there I was on a highway going 20 mph at 3000 rpm.

I heard some rattling noise (not sure if coincidence or not) and shortly after the engine continued to rev, but the jeep was slowing down as if it was in neutral instead but I had A LITTLE bit of power if I revved it up enough and I was able to get off the road. I end up rowing through prndl and get it back in drive and start again. Same thing happens, this time no rattle. I pull over again and that's essentially where I'm at. If I put the jeep in drive, it will NOT go forward anymore. No matter what transmission gear it's in and no matter if it's in 2wd, or 4wd high or low.

However, if I put it in reverse and I get it up to say 3000 rpm, it will start going backwards.

I cannot for the life of me figure it out. If I jack up the front wheels, the passenger front spins easy and free and the driveshaft springs as it should. If I do the same to the drivers tire, it is exceptionally hard to spin. As if the brake is dragging, but I can still turn it by hand, so I don't see how a 300 hp engine can't turn it.

I jack up the rear driver's side and it spun just fine in neutral. And locked up in 4wd as it should. Didn't do the rear passenger.

Key note, as I was driving, the vss was reading 0 mph. I figured the vss was bad on the 241c so I replaced it. That was why I think it wasn't shifting into 2nd. The pcm didn't know the jeep was moving... However, still no movement. There was some metal shavings on the 241c vss sensor. Weird for a transfer case that I just rebuilt.

So. What should I look at?

Please note, transmission was built from Novak adapters. Also, please note, the drive shaft does not spin when reving the engine. Meaning I would like to think the axle is good as if it wasn't, the drive shaft would spin while the jeep doesnt go.

Front axle is the stock Dana 35, rear is a Ford 8.8 from a junkyard. Internals looked good when I replaced the fluid, although the limited slip does not work anymore as I can spin a tire if it's off the ground while the other is on the ground.

So I know that was a lot, but I wanted to be as detailed as possible for the best help.

 

I don't know if this is your cause, but do you have a switch on the brake pedal to supply TCC/Brake Switch Signal to the PCM so it will lock up the torque converter when the brake is off?

 

Well I’m going to say check the fluid level.

 

I believe so. Novak conversions also reworked my harness
The directions were to splice into a brake light power wire and so I tied into my third brake light as it would only power up when hitting the brakes.

I know the Chevy pcm looks for power when the brake is not depressed, but I think Novak has it wired through a relay to give the computer the proper signal.

 

That's going to be my next step. It came full shipped, and I added a little more because I added an auxiliary cooler, so I would assume it's full, but I'll definitely check.

 

Torque converter was installed correctly? Common to make a mistake here, and can cause similar symptoms (unfortunately this usually destroys the pump in the trans).

Correct installation of the converter is going to be something like prefilling it with a quart of fluid or so, then carefully installing on the input shaft and spinning until fully seated. Some count clunks as it seats (3 clunks), but I like to measure with a straight edge across the bellhousing surface to the mounting lugs. Typically about 1-1/32 or so.. I've seen it listed as 1-1/64 to 1-1/8.

Also, did you check the clearance between the lugs and the flexplate before bolting it up? Here its usually 1/8 to 3/16" clearance required, not more or less.

And you've checked the fluid level is correct? Best way is to drop the trans pan and verify the full mark on the dipstick is level with the machine surface that the pan mates to.

 

So, torque converter came installed. Clunked in.

I'm not sure if it was this trans, or the junkyard trans I was going to install, but I began installing it and the torque converter didn't fit right as I was tightening the bell housing bolts. Didn't tighten them all the way, just noticed it wasn't quite right.

Spun the torque converter and it slipped in further, then bolted it up.

On this one, the gap between the converter and the flex plate was actually out of tolerance and too big, so I put a washer between each mounting bolt between the flex plate and the converter.. not sure if I ruined the pump that way, if I did, oh well.

 

New idea, so when in reverse, if I rev it up, it sounds similar to a manual transmission in reverse.. you know, a whine.

Probably the pump sucking air and cavitating. I'll check the fluid level next.

 

New idea, so when in reverse, if I rev it up, it sounds similar to a manual transmission in reverse.. you know, a whine.

Probably the pump sucking air and cavitating. I'll check the fluid level next.

What fluid is recommended dexron 6?

 

Whoever said trans fluid, you're right! About 1.75 gallons short.

 

Drove the jeep home. Today I learned how to properly fill a transmission.

When I originally filled it, I just poured it in, checked the dipstick, and saw it was full. Didn't know you had to let it cycle through and continue to add.

Thanks everyone!

 

download a manual for a vehicle that came equipped with that vehicle (silverado, camaro, whatever). It'll tell you to let it warm up, shift thru all the gears, then check it. Something along those lines.

 

Good deal,! I may have over filled it a little, but I've got a cooler line leak. I had origionally cut the lines at the rubber connection, then used barb fittings to connect to the aux cooler.

But I outsmarted myself and cut the hard line then put a flare on it and secured it to the cooler lines using a flare and AN fittings. Guess I didn't learn enough in my 5 months in airplane mechanic schools, because it's leaking at the an fittings. Lol

 

What happened was, you filled the pan (not much) but didn't allow the converter to fill (a LOT more!). I think some guys fill the converter as much as possible before putting it into the tranny.

 

Please check the oil level as well.

 

And the coolant and brake and transfer case as well as the differentials. You can let the windshield wiper fluid get low if you like.

 

Lol. All is good my friend. Changed the diff fluid while building this beast, added the transfer case fluid after rebuilding it, coolant is brand new and will be topped off after replacing the radiator, and oil is good as well.

 

See, the converter came preassembled in the trans, and since the trans only took a little bit of fluid, I assumed all was full, including the converter.

Lesson learned and I hope someone else can learn from this prior to sucking their pump dry out of their newly built trans!

 

I always fill the TC before I bolt up the trans. Depending on your cooler setup a completely empty 4L60E will take at least 12 quarts.
I just started my 80 Camaro LS3/4L60E for the first time last week. Before I started it I added 6 quarts of trans fluid. Then when I started it I ran for about 30 seconds and shut it down. Then I added 6 more quarts. Started it up again and the wheels moved in drive and reverse. It's a bit low on the dip stick but I want move it back and forth out of the shop and do the final top off. Too cold out the last few days to be outside.
Glad you got figured out.

 

Sounds like it may have been a good thing you didn’t have gas in it earlier.may have saved the transmission. ,