Break question.

[df2x4]

Thanks so much! I did have another question and i see you are a super moderator. Can I DM you?

Sure! But if it's a truck related question you may be better off just making a new thread in the appropriate section. There are a lot of smart people here and you'll get more eyes on it that way.

 

[man-a-fre]

Driveshaft yoke needs spline grease.

 

[Aqua]

Sure! But if it's a truck related question you may be better off just making a new thread in the appropriate section. There are a lot of smart people here and you'll get more eyes on it that way.

Thank you. I thought about it once you said that and that makes sense. The answer may be helpful to others. Appreciate it

 

[stutaeng]

Pretty sure that's what he meant. Read that thread I linked, even though you're dealing with a truck instead of an SUV I think it's still definitely worth checking out.

Is it perhaps on the 2 piece driveshaft vehicles? My ECSB has the 2 piece driveshaft. It's always had that clunk when you release the brakes. Greasing the center support slip yoke with the Zerk fitting made it go away for a little bit. But the last few years if I tried squeezing grease, it wouldn't go in. The grease would just come out of the little vent hole at the end of the yoke...so I just drove it like that.

Recently I replaced the center carrier bearing and noticed that splined part had like a plastic or vinyl coating on it, and it was starting to come off. I took off as much as I could, cleaned it and regreased it. I also welded that little hole. Not sure why it's there.

It's been okay so far, but haven't driven it much, so I don't know how it will do.

 

[GoToGuy]

I wonder why GM had two piece drivelines on alot trucks that work well with one piece. My 95 K2500 ECSB one piece, the 93 K1500 ECSB one piece, the 86 k3500 454 Reg Cab long bed, one piece. What determines other than a very long wheelbase (crew-longbed) a one or two piece drive shaft?

 

[Nad_Yvalhosert]

Have you checked for grooves worn into the drum backing plates? If the shoes get lodged in the grooves, then snap out and retract, it can feel like they were sticking.

 

[1998_K1500_Sub]

Sounds like the classic GM "stop-clunk" issue, caused by the driveshaft yoke shifting slightly on the transmission output shaft due to the rear axle shifting slightly when you let off the brake (break).

Three options:

(1) Ignore it or pretend it's a feature

(2) Disconnect the driveshaft at the diff, work the driveshaft (and yoke, which is the important part) back and forth on the trans tailshaft to redistribute whatever lube is already there; this should improve the situation. This solution works better if you've already done solution (3) below.

(3) Same as (2) except remove the yoke (yolk?) completely and apply some appropriate grease to the tailshaft, then reinstall. I'm not sure about the grease type; there's some concern about contamination of the transmission fluid in so doing. There's a GM TSB out on this issue (perhaps it's for other years; this problem has been around for a while) which might give you more detail (I remember in the TSB they specified a particular grease), or if you have a dealer friend or otherwise somebody you trust to get advise from.

 

[Supercharged111]

I wonder why GM had two piece drivelines on alot trucks that work well with one piece. My 95 K2500 ECSB one piece, the 93 K1500 ECSB one piece, the 86 k3500 454 Reg Cab long bed, one piece. What determines other than a very long wheelbase (crew-longbed) a one or two piece drive shaft?

If I had to guess, your 2 piece was steel and the 1 piece units were aluminum. Critical driveline speed is lower with steel than aluminum, aluminum shafts can be longer.

 

[Schurkey]

Yeah, it's driveshaft critical speed, which is enormously influenced by length (and also affected by diameter, and material the shaft is made from.)

This is why cars of different wheelbases sometimes had transmissions with different tailshaft lengths--larger cars got longer tailshafts, so that the driveshaft could be shorter and therefore more stable.

Novas, Camaros, Chevelles got the shortest tailshafts, B- and C-body cars got the intermediate tailshaft; and the D-body (Cadillac) got the longest tailshafts.

I was under a motorhome last week, they wanted me to change a starter and reconnect the driveshaft that had been disconnected for towing the stupid thing since the starter was dead and they couldn't drive it to it's new home. The driveshaft was in three or four sections with U-joints in between--all to keep the length of any one section within reason.

If the driveshaft is too long, or spun too high RPM, it gets floppy. As soon as it gets floppy, it instantly goes out of control. When the shaft breaks, it can flip the vehicle.

 

[454cid]

If I had to guess, your 2 piece was steel and the 1 piece units were aluminum. Critical driveline speed is lower with steel than aluminum, aluminum shafts can be longer.

I'd guess that has more to do with weight penalty associated with a larger diameter tube. The big aluminum shafts are much bigger in diameter..... they're like using a single pontoon for a drive shaft