Transmission, differential, drive-shaft issue...

[asullivangarner]

1996 Limited with an automatic transmission and 235k. Sometimes, but not always, when I start the truck and put in reverse to back down the driveway, the truck does not move. The first time was in cold, 30F, weather. The transmission does not appear to be slipping. Eventually, the there is an audible "ka-chuck" from the rear and then the truck takes off.

What I have done:

Checked transmission fluid; it was filled to the proper level and clean.

Put the truck in neutral and manually tried to rotate the drive-shaft. There is a degree or two of rotation; but the universal joints, on both ends of the drive-shaft seem fine.

What I have not done:

Paid someone to look at it!!!

Has anyone had this experience and/or does any one have an opinion about my next steps?

Thanks,

Andrew

 

[Four-CLT]

You may want to drain your rear differential and check if there is any metal in the fluid or on the magnetic drain plug. If metal is present, it could indicate some damage to the gears. I've been dealing with a similar issue for the last 6 months.

 

[Snowy21]

My first inclination would be to look at the drums and see if things are out of spec/gummed up. Have you fixed a leaking axle seal recently?

 

[Richard808]

If you put it in reverse and give it gas, does it rev up like its in neutral or like your brakes are pressed? Sounds to me like it isnt going into reverse right away possibly from the fluid being cold and not having enough psi to engage the clutch packs? Are you starting it and throwing it in reverse right away? Also not sure if it uses a reverse shift solenoid but most shift solenoids fail when its cold out from my experience.

 

[socaljohn]

On mine it's the parking brake releasing. Does it every time the truck sits for a while with the parking brake on.

It only does it in reverse and only when the truck has been sitting for a while with the parking brake on. If I don't set the brake then there is no hesitation or ka-chunk noise. It never does it driving forward regardless of whether the brake has been set or not.

 

[kball]

I agree with clund. This is a typical cold weather, leaking axle seals, gear lube getting on the rear brakes situation. Does the back side of your rear wheels have lube spraying out all over them? If so it's your axle seals leaking, if not I'd take your rear wheels and drums off and check the brakes. I bet they have diff lube on them, just not enough that its sprayed outside yet.

 

[Buckaroo]

I have had issues with delay dropping into gear - particularly in the morning when cold. For me, it was simply low ATM fluid (quart or less). The fluid level is hard to check accurately. The trans needs to be hot and you need to have it on a level surface....you need to move the gear shift down slowly through all the gears (clicking into each one and giving it 10 seconds or so) and back up (again, hesitating in each gear) to park. Then pull the stick with the engine running.

 

[Drcoffee]

Another possibility can be a weak battery. When my transmission was slow to engage, i read up on how the transmission solenoids rely heavily on pure battery power to activate before the alternator has a chance to provide power. After i switched batteries, my transmissions morning sickness went away.

 

[nobb]

Strange that it only happens in reverse. Definitely check your rear brakes before focusing your attention on the transmission.

Our 3rd gens have a silly design (compared to the older models) in which the parking brake line goes to some sort of pivot/lever assembly to activate the drums inside the brake. The problem with this lever is that the pivot point can seize up due to corrosion/salt/dirt/etc. So check to make sure the parking brake mechanism is working correctly.

Lastly, check your rear seals to make sure they arent leaking gear oil. Then check your drum brakes. Any bit of grease on them can cause grabbing issues, which is what I have experienced. You'd have to inspect them very closely. On my pads, it wasnt even that apparent that grease had soaked into them, but sure enough, they were grabbing. A hint that they are grease soaked is that the surface looks shiny.

 

[asullivangarner]

Sweet!!!

Four-CLT: I plan to change the rear diff fluid today, not sure what that will buy me, other than metal shavings and possibly a new rear diff, but at 235k it can' t hurt.

clund21: And pull the rear wheels and drum and take a look... Have you fixed a leaking axle seal recently? No.

Richard808: Revs up like brakes are engaged. Are you starting it and throwing it in reverse right away? No.

reverse shift solenoid No idea

socaljohn: I do not use the parking brake.

kbal: Does the back side of your rear wheels have lube spraying out all over them? I will know once she is up on jack stands.

Buckaroo: Fluid is GTG, but I have never check in the manner you suggested. I will add that to my quiver.

Drcoffee: Battery is new, new enough to crank without issue.

BTW: where is your coffee thread? My mother was Mrs. Coffee. I buy green beans and roast in the oven. Between Melitta and Chemex, I have no need for anyone else's coffee!!!

nobb: It now happens whenever I put the truck into gear, forward and reverse. Definitely check your rear brakes before focusing your attention on the transmission. Agreed!

Excellent responses!!! I greatly appreciate your time.

Thanks again,

asullivangarner

ps: I will follow-up after I jack her up and do some work.