1990 Toyota Pickup 4x4 manual transmission difficulties - trouble shifting into 1st from a dead stop

toyota
tacoma

#1

So, I bought the truck used and everything about this truck is great minus the shifting difficulties in first. With the truck at a dead stop, the clutch depressed, and the shifter in neutral it can be near impossible to shift into 1st (it’s possible with a lot - emphasis on a lot - of force). No grinding, clashing, knocking in the shift knob - it just wont go into gear. I can shift into 2nd-5th and reverse without too much difficulty. If the truck is in motion, once the vehicle gets between 2-5mph I can easily downshift into 1st. However, if I shift out of 1st and let the truck sit for, say, 5 seconds it is often very challenging to get the truck back into 1st.

I have tried to look up this problem online with limited success. What I found was it could be caused by:

  • something wrong with the clutch installation
  • a need to bleed the clutch (it’s hydraulic and, although the reservoir is full, the fluid is a bit dirty)
  • perhaps a faulty clutch master cylinder
  • play in the clutch linkage
  • a broken spring in the pressure plate
  • a bearing that is starting to go out
  • worn synchros in 1st

I am a machinist, not a mechanic, so it’s hard for me to evaluate these ideas (beyond the cost associated with each). Given my limited knowledge of transmissions and my good mechanic friend’s opinion, I think it’s a broken spring in the pressure plate.

Any ideas from you all? This is the original transmission in the truck, it has not been rebuilt (but has been maintained with regular fluid changes), and has a tad over 158,000 miles on it.

Thanks


#2

Adjust the clutch linkage ASAP. Forcing the shifter is damaging the syncronizers. I believe your truck adjusts at the bell housing. Adjust the rod out until it is too tight to spin and then loosen it just enough that it becomes free to spin.


#3

If I can avoid forcing the shifter (i.e. only shifting with the truck in motion, leaving the truck in 1st while at a dead stop, etc.) can I live with the problem for a while? I won’t be able to perform maintenance on the truck for another couple weeks and I certainly don’t have enough money to do much in the way of part replacement.


#4

It sounds like the clutch is dragging, not releasing completely…It will also grind going into reverse if it’s dragging…You can work around it by turning the engine off before you engage first or reverse gear…But once you determine that the clutch linkage is operating properly, the next step is to pull the transmission to see what is wrong with the clutch…Forcing the transmission into first gear will quickly damage or break some expensive parts…When you replace the clutch, you will replace it all, the disc, the cover, the pilot and throw-out bearings…You can purchase these parts in a package…


#5

Yes, the transmission grinds some if I try to put the transmission into reverse quickly. However, I can shift smoothly into reverse if I am gentle. I thought the grinding was due to there being no synchro on the reverse gear + the reverse gear being straight cut instead of helical. Am I wrong?


#6

Also, with the engine off I still have difficulty engaging 1st gear


#7

There is no syncro on reverse, so if the clutch is dragging, it will be very difficult to engage that gear with out grinding badly…Is the truck idling very fast?? If you can slip it into reverse without grinding, then the clutch dragging becomes less likely…I just noticed you said you have trouble going into 1st with the engine off…That means something amiss inside the transmission…Broken synchronizer, bent shift fork…


#8

No, idle speed is great (although this model year didn’t come with a tach on the dash so I am going off sound and experience driving the truck)


#9

Read my last post…I have edited it…


#10

The Mitsubishi 5-speeds are not a stout as the 4-speeds…They were used in millions of vehicles, so transmission mechanics are very familiar with rebuilding them…The 4X4 drivetrain complicates things a little…If you let the clutch out in NEUTRAL, do you hear any bearing noise from the transmission?


#11

No noise whatsoever. Also, I am pretty sure it’s a Toyota 5-speed transmission (unless Mitsubishi 5-speeds came stock on 1990 Toyota’s - again, I am a machinist with a mechanical background, not a mechanic)


#12

Virtually ALL the Japanese car makers used the Mitsubishi 5-speeds… But that’s really not important…


#13

So you’re thinking I need, at a minimum, a partial rebuild of the transmission? It’s a silly question but, if I am gentle with 1st gear (i.e. I don’t force the gear) could I keep driving the truck this way without destroying the transmission? I simply don’t have the money in the cards right now to perform that kind of maintenance.


#14

With a cheap set of combination wrenches and channel lock pliers the clutch can be adjusted in less than 10 minutes.


#15

So you think all I need is to adjust the clutch - I will give that a shot first seeing as it is easily done. Supposing Caddyman is correct and a shift arm is bent or synchro is burnt out, is it safe for me to still drive the truck (albeit, gently)?

Thanks all for the suggestions


#16

If you continue to drive with the clutch dragging you will eventually trash the transmission if it is not already trashed. Just look at that on a wager; 10 minutes/$3000. If adjustment doesn’t solve the problem make your next stop a qualified shop and assume that a complete clutch is needed.


#17

On your vehicle, I don’t think you will find anything to adjust…Hydraulic clutches are usually 100% self adjusting… You have all the symptoms of a dragging clutch except you say it will shift into reverse normally without grinding…That would be impossible with a dragging clutch…You also say it will shift into first normally as long as the truck is rolling…That eliminates the bent shift fork or damaged syncro…

This does not add up…


#18

It seems that the clutch is adjusted at the pedal. If the jam nut is loosened the push rod can be lengthened to remove excess play and the jam re-tightened.


#19
Caddyman:Virtually ALL the Japanese car makers used the Mitsubishi 5-speeds.

Not true for Toyota. They have their own transmission designs that are FAR superior to Mitsubishi. For this truck, I think the correct Trans code for the 4WD 5-speed is the W56. These transmissions are prized for their reliability and durability.

The hydraulic clutch is self-adjusting, and there are no mid-life adjustments to be made. If the clutch is dragging, there must be either a leak in the hydraulic release system or a mechanical failure at the clutch. This being a 1990 truck, I’d look for leaks. Peel back the dust cover at the slave cylinder to look for evidence of leaking, and also check under the dash for a master cylinder leak. The fluid can leak out and wet the inside of cabin under the carpet. To see if the clutch master cylinder is leaking internally, check the clutch lever movement as someone else presses the clutch pedal. if the lever stops moving before the pedal does, the master cylinder is leaking internally and needs to be replaced. Replacing both the master ans slave together will prevent you from having to do this again in the near future.


#20

Sorry for reviving an old thread, but no one had suggested that the way you can know if your synchros are giving out is whenever you get that resistance going into first, shift it into second and then back to first. Do the same with reverse, shift it into 4th and the back into reverse, it should slip right in. I’ve nursed transmissions with bad synchros for years by doing this. They just need a little help getting into position, shifting into second will usually get them there.