Slow switch into reverse. Need help.

[BlazerLT]

MY 1995 Blazer is ticking me off a little lately.

The transmission seems to be really slow transferring into reverse lately when going from drive directly into reverse.

Seems to take a couple seconds before it actually will switch over.

If you rev the engine a bit it will switch over faster but a little harsh which is something I really don't want to happen seeing the hard clunk into reverse can't be doing anything good for the unit.

The driveline is tight and the fluid was changed 6 months ago but the only thing I didn't change was the filter. The filter was changed 3 years ago and there is only 20,000-30,000kms on it.

Would a clogged filter cause this or could it be the pressure control solenoid in the transmission that is not holding up enough line pressure.

I figure this seeing as soon as a blip the throttle gentley it will switch over faster. But again, I know I shouldn't do that.

Any thoughts guys?

 

[Gary Allan]

All the time ..or just when cold?? Never mind ..it's always cold in Canada

j/k

 

[BlazerLT]

hehehe....true

This is usually when the engine is completely warmed up and the transmission has been running for over 10 minutes or so and up to temperature.

I am also getting a very intermittent soft shift to second.

Some people are saying it is the main pressure solenoid.

 

[Dark Jedi]

I will ask a stupid question. did you use the right fluid? or is it the same fluid type you always used. could try the filter and try and save as much of the fluid you can and reuse if you want. instead of starting to replace items that costs alot and nothing wrong with it.

 

[BlazerLT]

Yes, the right fluid was used for this transmission.

When cold it seems to switch fine, a little slow, but not as bad as when warm.

 

[CBR.worm]

I believe in a lot of transmissions reverse is the same gearset/clutchpack as second gear. Sounds like low line pressure - which would be better when cold. Could be the solenoid, or improper fluid. It is possible that it is the filter as well - but I would think that unlikely unless something else is going on.

Is the level correct low?

In the last A/T shop manual - one of the tests to perform during troubleshooting was to record the amount of time to fully engage Reverse from drive. I don't remember what that indicated though.

 

[BlazerLT]

I will check fluid level tonight just in case.

The filter might need to be changed, it is due.

It just seems the warmer the temperature, the more the problems come up.

Also, when accelerating briskly, there is never a shift problem, only when pulling away normally will this sometimes occur.

 

[Mud]

The valve body may have enough internal buildup that it takes a little bit of revving (increasing line pressure) to move one of the valve pistons. As the valve body warms, the expanding fluid and metals help to alleviate the condition.

IMO to always change the fluid and the filter. You would be surprised at the amount of debris a filter can accumulate in a relatively short period of time. Also my view that 3 years and 20-30K kilometers is enough reason to change the filter. I do this at 30K mile intervals on all of our vehicles.

Your least expensive alternative at this point is to change the filter and fluid. Then you can see if the problem is more mechanical than hydraulic.

 

[BlazerLT]

Yea, good point.

I will have it changed within a couple of days.

 

[TonyMazz]

Can't you use some ARx in the transmission too...may be clean out some real debris....

 

[BlazerLT]

That one I am hesitant to use right now seeing the fluid is practically new in it. I might drop some in before the next change.

 

[04SpecV]

How many total miles? Is that a 4l60E? What kind of fluid did you use?

It sounds like you need something that can clean.

 

[BlazerLT]

Yes, it is the 4l60E.

143,000miles

Fluid is still perfectly cherry red after the last change.

I was told the new Dexron fluid is practically mostly detergent and nothing else is really needed.

Your thoughts?

I just don't want to ruin a new fluid batch with an additive that isn't needed.

 

[Gary Allan]

As was said, the warm aspect of the symptom points to a viscosity/pressure issue/relationship. You've got enough pressure when cold ..not enough when warm. It also doesn't occur under high speed (rpm) situations ..where the trans pump is shunting excess fluid back to the sump (it too is much like an oil pump).

It would (or could) just be the sticking valves and whatnot that merely require more pressure to actuate. In my experience, however, this usually is evidenced by a "harsh" shift that's late for the throttle/load situation ..since instead of a 2000 rpm shift ...you're now at 2500-2800 and snapping it into a lower gear with far less of the normal throttle/load that is usually associated with that rpm.

If you're reluctant to use Auto-Rx, why not some solvent based agent that will evaporate after it has disolved any of the varnish like build up in the fluid pathways??

 

[mjo]

quote:

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If you're reluctant to use Auto-Rx, why not some solvent based agent that will evaporate after it has disolved any of the varnish like build up in the fluid pathways??

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I have a similar problem and cannot afford Auto-Rx. What solvent do you suggest, Gary? When it cleans it out should I keep the dipstick loose to allow the solvent to leave the transmission?

 

[BlazerLT]

I am just wondering if I should just have the main pressure control solenoid changed seeing it is a problem with this truck.

 

[04SpecV]

How much is that new Lubegard flush?

quote:

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THIS PRODUCT IS NOT A CHEAP ZINC-BASED PRODUCT THAT IS HARMFUL TO YOUR TRANSMISSION. THIS PRODUCT CONTAINS LUBEGARD'S PATENTED LXE® (LIQUID WAX ESTER) TECHNOLOGY THAT THE (OEM'S) AUTOMOBILE MANUFACTURES USE AND ENDORSE. NO OTHER COMPETING ADDITIVE CAN MAKE THIS CLAIM.

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I did a AutoRX treatment on my 93 4l60e it helped a ton for it slamming into 2nd gear. But I'm only at 118,000 now. Before that I changed the filter, and all the fluid(Original?) which did pretty much nothing.

 

[Gary Allan]

quote:

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I have a similar problem and cannot afford Auto-Rx. What solvent do you suggest, Gary? When it cleans it out should I keep the dipstick loose to allow the solvent to leave the transmission?

---

We have a spray cleaner here 2+2 ..but it looks like regular carb cleaner ..although this is the first such product that recommends spraying it into the trans fill tube for 30 second to restore smoother shifting.

I would think that most of these type products are volatile enough to evaporate out at normal trans temps.

 

[TonyMazz]

Pull the valve body and check the bores. probably getting sloppy, gunked up and needs to be throughly cleaned, and / or replaced. it's got 140K and its time ....

 

[BlazerLT]

The change to second is weird.

Your will be accelerating and it is almost like it isn't holding. Kinda like the switch coming in to soon.

Odd how it is so infrequent.

It will be fine for days and then it appears again. It might be fluid starvation.