Fulid change

[Xxl2]

I have a 1991 c 1500 long bed regular cab. It looks like the transmissns tail rests on a cross bar. will the trans need to be supported if i remove the cross bar? If so where is the best point to put a jack stand I want to drain athe fulid and change my filter

 

[stutaeng]

I have a 1991 c 1500 long bed regular cab. It looks like the transmissns tail rests on a cross bar. will the trans need to be supported if i remove the cross bar? If so where is the best point to put a jack stand I want to drain athe fulid and change my filter

No need to remove the rear tranmission crossmember to remove oil pan.

Only if you are dropping the tranny and/or removing it does that crossmember come out. And support the tranny with a 2x12 on the oil pan so you don't dent it...but again, not necessary for oil pan drop.

Does your tranny have a drain pan?

 

[Schurkey]

No need to remove the rear tranmission crossmember to remove oil pan.

Yes. Exactly right.

Does your tranny have a drain PLUG?

FIFY.

The trick to dropping the fluid if there's no drain plug, is to disconnect the lower trans cooler tube (transmission-to-cooler tube) at the radiator, cram a rubber hose on the end, and direct it into a drain pan.

Start the engine, let the trans pump move the fluid from the trans pan to the drain pan. As soon as the fluid shooting out of the cooler tube starts to sputter, shut off the engine. 90% of the fluid that was in the pan is now gone--so the pan comes off with less mess.

Once the pan has been cleaned, and the new filter installed, put the pan back in place, fill with about 5 quarts of fluid. Open another ten-ish quarts so they're ready to pour.

Start the engine, dump fluid down the dipstick tube as fast as you can pour it.

When the fluid squirting into the drain pan is as virgin-red as the stuff you're dumping in, shut off the engine. Your drain pan now has 12+ quarts of old, dirty fluid in it. Reconnect the cooler tube. Start engine, top off fluid as needed.

Have a beer. You've just flushed almost all the old fluid from your trans.

If you want to do this even better, buy a short length of pre-flared tubing from the parts store, remove the UPPER cooler tube, (cooler-to-transmission tube) install the new, "temporary" tube so that it empties into your drain pan. This way, you flush the trans cooler, too.

Make sure the new "temporary" tube has the same flare system as the trans cooler tubes on the vehicle--some newer vehicles don't use the old-style double flare.

 

[Xxl2]

How am I going to get the back bolts off ? Also do you think I should change the trans mount ? Are they hard ? If so what are the good brands of mount

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[Schurkey]

I hate when they do that. Fookin' engineers that have never gotten their hands dirty doing anything useful. Consequently, they have no regard for the efforts of others. Dirtbags.

Unbolt the mount from the trans or the crossmember--whichever is easier. Lift the back of the trans an inch or two with a floor jack for access to the bolts. A (13mm?) socket with universal joint--or a swivel socket--especially in 1/4" drive for access, and whatever you need for extensions 'n' a ratchet.

Don't replace the mount unless there's something actually wrong with it. Aftermarket rubber mounts are cheap Chinese junk. If you HAVE to replace it, get Polyurethane or OEM rubber.

 

[Xxl2]

It clunks every time i put it in reverse. I know my motor mounts are a bit worn.

 

[Schurkey]

It clunks every time i put it in reverse. I know my motor mounts are a bit worn.

When my truck did that, it was from excess play in the worn-out, crappy, weak 8.5" rear axle.

I wouldn't expect the trans mount to cause a clunk noise when put in gear. U-joints or engine mounts, sure. Worn bushing or splines on the driveshaft yoke, maybe. Rear axle, certainly.

 

[Xxl2]

What is the sign of bad trans mount ?

 

[alpinecrick]

What is the sign of bad trans mount ?

The trans moves a lot when it's put in gear.

I'm lost. What are we doing here? Changing the trans fluid? Changing the trans? Or figuring out the clunk?

Don't discount the classic "driveline clunk" from the splined driveshaft yoke coming out of the trans side.

 

[Xxl2]

I wanted to change the fluid frist then I thought if the mount is bad I could do that when I had the trans under bolted from the mount it's the original mount 394000 on the mount