Our beloved 80 has developed a slight shift problem (1 Viewer)

[HercDriver]

Truck has 196,00 miles, serviced well thru 100M, and mostly kept current since. 6000 miles ago had transmission pan dropped, fluid drained, screen cleaned, fresh toyota fluid added(mechanic does not recall which toyota fluid).
Truck ran great, shifted smoothly, no problem.
Recently noticed reverse has become very abrupt when shifting from park to reverse. Not a really big deal at cold start since engine is on high idle. But the problem is now the same when engine warm. Recently, when backing the boat into the lake, and shifting to Low(not low range) for the pull out, nothing moved, acted as if in Neutral. Shifted to park, shut engine down restarted shifted to Low, and continued with no further problem. Now when backing (backing only, so far) the transmission will shift out of gear. Recycling shift lever seems to settle the problem immediately(so far).
I have noticed the gear position indicator lights on the panel do not illuminate except when in 2 position with stick.
Any Ideas?
1. Neutral Saftety Switch corrosion?
2. Wrong fluid at change...new WS Spec, too viscous?
3. New fluid cleaned some old wear debris and deposited it in a valve or screen?
4. Internal issues needing a real service expert?

 

[CruisinTiger]

I have a similar problem with my honda accord except it is in the driving forward part. My Transmission Computer Module has gone bad. I have to shift it to 2nd and once the RPM's are up I can shift into 3rd. It's in saftey mode and will not shift automatically. On the Honda's the D4 light will stay lit all the time. I went to a very good honda mechanic and found out the problem. I just have to replace the module which is on the passenger side floorboard and it will fix the problem. I don't have an 80 but I imagine there is some kind of electronic computer that controls the shifting...so your computer may be going bad. Knock on wood but I don't think it is something mechanical but an electrical issue. May have to fork out the 90 bucks to get a diagnostic test done on it. Good Luck

 

[Trollhole]

Ken when you had the fluid replaced did they do a flush?

 

[HercDriver]

I am 90%sure he didn't. I will ask this am

 

[Hard40]

Wish I could help but my tech is severely limited on 80 transmissions. However it does sound like a fluid problem rather than something more serious. Good Luck.

 

[GXO]

Sounds like it is low...you got on an incline and starved the pump and it slipped.

 

[concretejungle]

I"m no expert here, but i'm leaning towards your #3. Or, Dan's suggestion above.

 

[HercDriver]

Dan,
Elaborate. I have too little knowledge of the working of the trans to read the occult message you are sending. Thanks C.Jngle but have same ignorance.
K

 

[concretejungle]

I don't know that much about transmissions, other than what i've read on this board. . . but from what i can remember, a trans. flush may dislodge small debris and move it through the system until it get's lodged and possibly plug a van or valve, starving parts of the transmission of fluid.

Or, like dan says, it's just low on fluid.

armchair diagnosis here......

 

[GXO]

If your tranny was drained and refilled you may not have had the same amount taken out put back in. The fact you mentioned that they drained it, cleaned it, and assembled it makes me think they did not do a power flush.

Power flushes are bad. They dislodge, etc as people have mentioned. There are machines that use the truck's pump to move the fluid and those are okay to switch out fluid in situ.

Now, your symptoms of slipping and surging are usually symptomatic of insufficient flow of fluid or degraded/wrong fluid. Seeing as the mechanic probably used ATF that was clearly marked "ATF" I doubt it would be the problem. ATF of any kind would run the tranny in your truck to my knowledge.

So, if you had no problem pre-service, and you have the situation after...I am thinking you have either:

1. insufficient fluid in the transmission. Run it until hot, park flat, wait 5 minutes, and check the level.
2. a blockage of some sort in the valve body or screen in the transmission.

Either way, I would say you can check #1 yourself, and both should be fixed free of charge by the mechanic.

Is that less cryptic?

 

[HercDriver]

You elucidate with alacrity, my cryptic friend!

 

[Trollhole]

Still has this issue. I'm thinking it has something to do with the fact that non of the shifting lights on the dash work.

 

[BMThiker]

You mean you didn't get a power train warranty with that rig? Well I guess lights aint' part of the powertrain...he-he.

 

[concretejungle]

he hasn't said if he's checked fluid level yet has he? maybe i missed it....

also was thinking that maybe his shifter linkage needs adjusting?

 

[informationjunky]

Mine had the same problem until I put a lift on it.

 

[GXO]

Shift linkage could be out of spec, also, the shift cable could be out. I adjusted mine in 5 minutes and it made a big difference.

 

[HercDriver]

How about another good soaking in the Chattooga?

 

[HercDriver]

Mine had the same problem until I put a lift on it.

ROFLMAO!