Tsword

I recently purchased a 1997 Tacoma with a 3.4L, 5 Spd and 4x4. When I bought it, the truck had issues staying in 1st gear. Every time I start in 1st it pops out when i move. I can push on the shifter and sometimes it stays in gear. When it pops out under load it makes a loud thud. Every other gear shifts like butter no problems what so ever.

I checked everything I could before pulling the transmission. I checked the shifter bushings and the Retainer balls/spring. Everything looked fine... so I figured the issue was inside the trans.



I pulled the transmission out and opened the case hoping to find an obvious problem. Unfortunately this wasn't the case, everything looks great inside the transmission. The shift forks look fine no noticable wear, the syncros are in good shape, no warn gears, shift rod and retainers look fine. I had my friend who works on transmission at a GM dealer and he said it looked fine to him.






Has anyone ran into a similar issue? Any Suggestions?

One thing i did notice, the 1st/2nd synchro hub seams to slide further on to 2nd gear compared to 1st gear. It covers 1st gear about half way. When I shift into 2nd its covers the gear about 3/4 of the way. on the 3rd and 4th synchro hub it seams to completely cover both gears.



1st Gear




2nd Gear


Shift fork

zukijames

its really hard to tell from pics. I know its dumb but was the shifter hitting on anything.. How are your motor mounts and t case mounts?

Tsword

[QUOTE=zukijames;52301174]its really hard to tell from pics. I know its dumb but was the shifter hitting on anything.. How are your motor mounts and t case mounts?[/QUOTE

Yeah I checked to make sure it wasn't hitting anything. I pulled the shifter boot off and drove it around but It didn't help. The mounts still good nothing's torn or anything. I'll snap some more pictures and get them posted up. Thanks for the reply!!

Malcolm99

Not the same transmission but I had AWD Mitsu transmission that would pop out of 5th gear, replaced the 5th/rev hub $yncro and I never had a problem again. From the research I did it was either the Syncro was worn out (perhaps the locking retainers and the springs) or the bearings on that gear set where worn causing play, or on my specific Mitsu transmission the retaining nut was known to come loose causing play in the gear set causing it to pop out of gear (tightening the nut did work in my case).

wyoming9

iTrader: (1)

Are all the bearings tight no roughness ??

Once there is enough play in the bearings it allows things to move .

It sounds like enough bearing wear 1st gear is not engaging completely like it should allowing it to jump out.

Since the transmission is out and apart I would hope your putting all new bearings in.

After all all the hard work is pulling and installing things

DOT3

My guess would still be shifter bushing fragments piling up. I've seen this come up occasionally on several forums.

wyoming9

iTrader: (1)

I would hope if one is good enough to rebuild a transmission that would have been one of the first things checked.

When the shifter bushings were replaced .

Tsword

I know the shifter/bushings are good.. To double check I mocked it up with the shifter installed and the gears exposed. The shifter wasn't limiting the travel of the fork, it moved it to the same position.

The bearings seam good, they don't make any noise and have very little play in them. I would need to tear it down further to confirm this.

Earlier I said it looked like 1st/2nd gear synchro hub wasn't completely engaging the gear. Looking closer it looks like the hub engages the same distance on 1st and 2nd gear. Now the 3rd/4th hear hub sides completely over the gear.

With 1st gear engaged....


2nd gear engaged.....


Now this how 4th gear looks when its engaged


Im not sure if this is normal, this is my first transmission I've taken apart but I'm starting to understand how everything works.

Im trying to decide if I should rebuild it or buy one off craigslist. It would be nice to find the problem and know exactly what needs to be replaced.

83

Sorry to defer you elsewhere...but have you tried the Marlin Crawler forum? People who know the inner workings of a transmission are rare, and finding people who know how a transmission gear should look and line up are very rare.

You're a bit more likely to find knowledgable help on that forum, since Marlin specializes in transmissions.

Malcolm99

You will want to replace 1-2nd hub synchro as that is what holds it in gear, you will have to remove and press the gear set apart and remove all the bearings to get to the hub synchro, you will notice that the bearings surfaces have lost most of the hard surfacing and will need replacing so your best bet is to buy a complete assembled 1-2nd gear set if available assembled, if not it's cheaper to replace the entire tranny with a low km's. Yes if the bearings have enough play it can shift the gearset and pull on the shift fork pulling it out of gear as the shift rails are fixed, but either way with the amount of work involved your best to replace everything on that gear set or the tranny IMO