I have a new issue that started last Friday. When I put the truck in gear and let it begin to pull itself, drive or reverse, it has a strange jerking or slipping deal. It doesn't happen every time but when it does you can feel it in the drivetrain. I took it to the shop that did the motor work and they ran a diagnosis(while I watched) on the motor and its turns up nothing. It runs perfect, shifts like it always has, but just has this jerking/slipping thing when I let off the brake and it starts to pull itself. If I go from brake to throttle its fine. I had the rearend diff worked on to fix the leaky ring and pinion seal and the differential cover sealed at the dealer last month. I searched and don't see anything like what I am experiencing. Could my tranny be giving it up now? It has never been overworked and never overheated. I had the full fluid service done at about 70k and now it has about 130k on it. Thanks in advance.

 

When was the last full trans service done?
Full fluid exchange and filter of a dump and fill?
Might be time to do it if it'd not been done in
resent history.

One other thought. Pull the drive line and clean and re-grease
the slip-joint with the correct Ford grease XG-8 PTFE Lubricant

You will need a set of clamps and some oetiker pliers. They look like hoof nippers with blunt
rounded edges so that they don't cut the clamp.

Sean

 

I think its overdue, 60k, for the full transmission service. They did the slip joint when they did the ring and pinion. It was clunking like they all do, but now its not. I am just a little hesitant on the transmission service when the truck has high mileage. I've heard people say it does more damage than good??

 

The 5R110W aka : Torqueshift does not like dirty oil.
Shift timing is dependent on things happening in
a very precise timing order and dirty oil can be a problem.

One think to keep in mind. DO NOT let anyone use any any type of
conditioner in the oil before or after. That will destroy the trans.
At the bare minimum dump the oil in the pan and replace the remote
filter up front. That is about 8~9 quarts. What you want sone is just
a heated exchange and not a "flush". You can do the 8~9 Quart exchange
at home. If I were in you place at this point I would pull the pan and
the internal filter (not because it dirty) You will get more oil out that
is trapped over the filter in the pump housing. You need a plastic hook
or body panel tool that is plastic to get the seal that will most likely
not come out with the filter. The pan gasket is reusable rubber seal
type. Clean the pan and magnet. When you pull the filter watch out if
will dump more fluid at that point. Then do the front filter and refill
with the same amount that you removed. I used a plastic painters
mixing bucket to get an exact amount that came out.

One upgrade some guys are using is the later 08+ pan and filter.
It is a full flow 100% filtering unlike what we have right now with the
bypass filtering. The filter in the pan is just to catch the big stuff and
I may get some grief over telling you to change it. It's just a tad finer
then window screen, But it does hold a but more fluid behind it in the pump.

Some ? of the guys have used compressed air to blow fluid out of the cooler
lines to get more out of the system.

Sean

 

Yeah, I've heard that, too. It isn't true.

What often happens is that the transmission is ignored and the fluid never changed. Then a problem develops. They decide to change the fluid, and then the transmission fails. Never mind 200,000 miles of neglect, it must be the new fluid that destroyed the trans.

That's a load of BS. What destroyed the trans was running on old fluid. New fluid didn't fix the damage the old fluid did.

While it's good for the trans to change the fluid, I don't think it will fix this problem. Your symptoms are exactly those of a binding slip yoke in the driveshaft. I know you said the dealer lubed it last month, but did they really? And what lube did they use? If they used the wrong lube it's all gone by now.

 

Another WAG would be to check if you might have a caliper sticking till you give it some go.

 

I thought about the caliper hanging also and honestly that is what it feels like. I am going to call the dealer and see if I can bring it in and have them look at the slip yoke while I wait. Since they did work on it I think that's the best place to start. If it is the slip yoke, is there a problem with driving it until they look at it? Can it do any further damage?

 

Have you checked the center support bearing on the rear drive shaft to make sure it isn't worn out. A bad bearing will allow the shaft to move up and down making the truck feel like it's slipping. It might be worth a look (if you haven't already), it's an inexpensive and easy job it that is the case.

 

I'll check that too. It just seems unusual that it began a few weeks after they serviced the rearend. Makes me think they did something wrong.

 

You already know the Transmission fluid should be changed.....

Since this is happening soon after the rear diff work....you didn't state if it only does the jerking while turning only, or it does it at any time. If it only did it while turning, I would suspect that no limited slip additive was added after the rear diff work. Is there any sound associated with the jerking?

 

I'll try to describe it in detail. It only does it after the truck is put into drive or reverse, or after stopping at a stop sign or light, going straight ahead, basically at idle when the truck is starting to pull itself along. It feels like the the motor has shut down for a fraction of a second, then catches and jerks the truck forward or back. But it's not the motor. The motor is running perfect across the board. It's not harsh, but even my son in the passenger front seat can feel it. It doesn't do it every time and I can't pinpoint anything that causes it like on an incline or going down hill. As soon as I apply a little throttle it goes completely away. The transmission is shifting perfectly and there are no other symptoms. I scheduled it for the shop that did the rearend to look at it Monday. I think that if it was a caliper grabbing it would do it more often and not be so random. I think it will turn out to be something simple.

 

No sound I can hear and I've been driving with the windows down.

 

Sounds (and "feels") exactly like the slip yoke to me. Been there a few times. Dissasemble and clean thoroughly and lube it with the Ford PTFE grease that Yahiko mentions in the above post. It is expensive (and a pretty blue color) but in my case it works well.

 

The funny thing about it is that it is very thin and you would not think
that it would do the job but it does. 2 trucks that would clunk if let sit for more
than a few weeks and when I switched from grease to the XG-8 I never got
a clunk again after that.


Sean

 

Its at the dealer. The shop foreman got in and it clattered before we left the garage staging area. He suspects limited slip clutch pack which means they didn't service it correctly. I started a new thread for it.