2002 Manual Transmission Shifting Issues

[RPM23]

2002 Ford Ranger 4.0L V6 4x4 5 Speed Manual: Cannot shift into gear regularly/periodically when engine is on. Shifting when engine is off is easy, with rare binding or getting stuck but generally easy. While engine is on, shifting up to other gears and back to first sometimes allows it to get into gear, but sometimes all fears are locked up and engine needs to be turned of and then shifted into first before restarting the engine and driving. Clutch has engagement, the rear has been jacked up and shifted into first and there was no lag when clutch is released from the floor, no suspected air in the system, but the fluid may be old. When car has been driven for a while or is warm, little to no shifting issues. What could the possible issues be and what are the solutions? New ATF mercon 5 was drained and refilled ~6k miles ago

 

[franklin2]

The transmission locks up sometimes after shifting? If that is the case, that tells me someone has been into the transmission, and did not re-install the shifter interlock pins and springs.

What I am familiar with is the earlier 5 speeds around 1984-86. I bought my BII cheap because the 5 speed was bad and pulled out. I investigated what happened, several of the teeth were sheared off on the front two gears. After further investigation I found the shifter interlock springs and pins where not installed. This allows the transmission to be in 2 gears at once, and that locks it up. Must have happened at speed on this trans and sheared the teeth off.

What trans do you have?

 

[SenorNoob]

02 4.0 Manual has to be the M5OD-R1. Maybe the M5OD-R1HD. Unless somebody swapped something else.

Was Mercon V acceptable by then? I didn't think it was.

I read that as hard to shift till it warms up. Maybe not?

If it were mine, I'd consider a fluid swap to Dexron/Mercon. Then try to find a way to check pilot bearing...

 

[RPM23]

I have the M5OD-R1 (M5R1), the fluid was drained and filled with Mercon V around 4-5k miles ago. The truck has 204,500k miles on it. When its warm it shift ok, still somewhat a pain to get into first from stop and second is a little rough but the upper end gears are smooth

 

[Roert42]

Slave cylinder leaking causing the clutch to not disengage fully?

Worn synchros?

Both?

 

[RPM23]

Maybe internally? No signs if leaks around the slave cylinder or master

 

[Roert42]

Only takes a small leak to suck in some air bubbles over the miles.

Once you have air in the line, it doesn’t work its way out.

 

[RPM23]

I was planning on bleeding it, but my friend who was going to help didnt want to risk introducing air in that process. I think the first step should be bleed it, via gravity or vacuum it, then also switching out the trans fluid to something a little thinner maybe

 

[Roert42]

The issue with bleeding is in the design of the mater cylinder, There is a high spot that traps air.

I’ve heard people theorize different ways to bleed the master in the truck. 1. Just pump the clutch pedal like a crazy person and hope the air works it way out. 2. Push the clutch in super slow and then slip your foot off so it spring back.

I have not had luck with that. Only way I found to bleed the master was to take it out of the truck and hang it in a way that allows it to gravity bleed.

 

[gw33gp]

Those are also symptoms of a bad pilot bearing. The needles in the bearing can get worn enough to get crossed up and bind on the input shaft of the transmission.

Bleeding the master cylinder in the vehicle is not easy but it is better than taking it out to do it. You must remove it from the firewall then turn it upside down. You can then pump the piston by hand until it becomes firm. This allows the air to go back into the reservoir. Before doing this, there is a way to check if the master has air in it. Disconnect the quick connect fitting to the slave. Then push in on the clutch pedal. If it is a hard pedal, you have no air in it. If it gives before becoming firm, you have air in it.

I had a slave that kept getting air in it and had to bleed it every two to three weeks. I did not leak a drop of fluid but somehow kept getting air in it. I just gave in and bled it once it started to get hard to get into gear. I did that for about a year and finally it occurred to me that it might be the O-ring seal on the quick connect fitting. I replaced that O-ring and found the old one had a nick in it. Problem solved. It doesn't make sense that it would leak air in but not leak fluid out. It makes no difference. I am just glad it is working right again.