Slip Yoke Thunk (yes another thread/post)

So my 98 5MT never had axle wrap or any slip yoke thunk.

My 04 AT has something. Trying to figure it out.

Symptoms: not all the time, but sometimes, when coming to a stop I hear/feel a clunk/thump under the footwell. Sometimes I think I can see the auto shifter move significantly.

Similarly when I’m going to start and and take my foot off the brake and start to roll, another thump/clunk of the same nature.

Never noticeable at any other speeds.

One thing of note: the auto transmission whines. Could be a transmission pump according to my mechanic. Maybe a torque converter, I don’t know?

History: Don’t know much about the maintenance history of this truck. Original owner owned it for 14 years. Traded it in to a dealer (to buy a 3rd gen). The accountant at the dealership bought it and owned it for 4 months before selling it privately, so he could get into a 3rd gen.

So I don’t know if the drive shafts et al were routinely greased.

Regarding axle wrap: the rear springs are original and shot. However in my 98 they were much the same way for years before I swapped suspensions. And in my 98 I never had axle wrap symptoms.

Last question: I’ve watched @Timmah! ‘s two videos regarding the slip yoke (thank you Timmah!) Just wondering if I go that route of manually packing it with grease, if there’s signs to look for that the slip yoke is shot due to no maintenance for the first 15 years of its life (other than obvious teeth wear)?

Also, if it’s okay to pack that much grease into the slip yoke without causing back pressure issues on the transfer case.

Thank you TW

 

there is grease and then there is this ...

$17 Genuine Ford Fluid XG-8 PTFE Lubricant - 3 oz.

https://www.amazon.com/Genuine-Ford-Fluid-XG-8-Lubricant/dp/B000NU77DA

 

Yeah that’s the stuff I’d go with per Timmah!’s video.

Just trying to figure out if the slip yoke is actually my issue before tearing into it.

Granted, I’m always of the mindset, “we’ll it can’t hurt...go for it and see.”

 

Yea. I thought my eyes were playing tricks on me when I would see the shifter move occasionally on stops or starts.

Also there have been a few times when as soon as I was at a complete stop, that I swear a car tapped me from behind.

I attributed both of these phenomena with having a lunchbox locker in the rear, which in turn causes I bit more play in the driveline from what I've read.
Now, I wonder if it's just normal.

Are you also experiencing the "ping" when shifting into D or R when the driveline is under stress from being on an ever so slight decline/incline?

 

Not so much a “ping” but a “thunk.” That I attribute to the transmission being under stress/pressure from the decline/incline.

God, I wish this truck had the R150F in it. lol


And yes, same symptom I have when coming to a stop/start. Feels like something tapped me from behind (no homo).

I guess a question I have is if it is the slip yoke, would I feel it so prominently under foot all the way up front?

 

I have an 04 AT 4x4 and I have had the exact same issue/symptoms you described back when my truck had the OEM leafs. Greasing the slip joint helped alot, but didn't completely cure it. The frequency of having the thunk went way down but still happened. I switched to Deavers (roughly 10 years ago) and almost never have the issue. I still grease the slip joint once every 2-3 years or so.

 

Subbed because I feel the same thing and wondering what exactly it is to fix

 

Awesome. I figured that, like much in life, it’s not a black or white issue...that it’s probably a combo of things.

Sounds like I have both issues going on.

Slip yoke I’ll probably do this weekend. Suspension swap incoming...

 

Glad I could help in some way. Love what you did with your '98, can't wait to see how the '04 turns out.

 

Thanks man. It’s bittersweet. I’ll probably sell my 98 here soon.

Which is like selling my heart.

Haven’t really bonded with this 04 yet. But with 3 humans and a 55 lbs doofus dog, the xtra cab simply does not work for us.

 

I'll probably be in the same situation in about 5 years, not sure how I feel about it at this moment

 

This ^^^
I had the ping noise from D to R. After I torqued the carrier bearing retainer nut an additional 20ftlbs over the 51ft lbs the FSM says the noise went away.