Trans slams on to first before stop

[pax]

After running awhile, trans slams into first gear, just before the truck slow down to a stop. It only does it sometimes, may be once a day.
The ABS kicks in sometimes when it does it. I pulled the ABS fuse out just in case it was the ABS locking up. But the transmission still slam into first, it was not the ABS.
Fluid level is good, oil looks good. Oil and filter changed last year.
Is it the transmission started going out? This is the original transmission with 280,000 km on it.(160,000 miles).
I am not complaining, just wanted to know if I am expecting an overhaul soon. Other then that, it up shift and down shift to any gear is ok. I can live with it for now.

 

[BuffaloXplorer]

I had an eerily similar situation. When slowing down, you'll hear the tranny clunk and then a ABS activation, causing the vehicle to extend the stopping time (?). Every morning i drive on an expressway that ends at a stoplight. It occured most frequently at that point. Also, when hitting a small bump while slowing down it would do it.

Shortly after this problem appeared, i replaced my rear shackles (not thinking they were related to my problem - one side had rusted through completely) and the problem has not happened again since.

The shackles were $33 for two @ Ford and it cost me $150 to have them installed (i couldn't break the OEM bolts free).

I'm guessing that the weakened shackle allowed the leafspring on that side to shift, allowing the axle to move, causing the tranny to screw up. Sounds like a reasonable explanation to my problem (?). The repair was made approx. 1 month ago and it hasn't happened since.

Check yours out

 

[BuffaloXplorer]

Coincidentally - i have approx 160,000mi on mine as well - but i've already rebuilt the tranny & tc.

 

[pax]

I am in the salt belt area like you are at. Hey, we are neighbours. But my X is way better shape then yours, at least at the rear. I don't think my (truck) rear end is as bad as yours. I better take a good look at my rear end after work to-day. Just to make sure it is not the leaf or the shackle caused my problem.
Thanks

 

[compdoc777]

Mine is doing the same thing after a tranny rebuild. I am thinking also it may be your universal joints, also the rear tranny mount could be bad as well.

Mine also make a krunching sound and feeling when I take off while turning.

My friend who works on Fords professionally told me it was the UV joints.

 

[pax]

I had a good look at the shackles and the leafs at lunch to-day. The shackles are rusting out too, but not as bad as BuffaloXplorer's. I hit it with my keys, they seems to be in one solid piece.
Looks like may be I am on the wrong track blaming the Transmission. I hope you guys are right. I am going to drop the rear axle drive shaft to check the U joints.
When I lubed the rear slip joints a few weeks ago, hoping that was the cause of the clunk. I just pulled back the boot to squeeze the grease in. That wasn't the cause, it still clunks after.
I checked the U joints at the time, they seems to be ok. No plays when I was twisting the drive shaft by hand. I guess I have to drop the shaft to check it properly, when I find the time to do it.

 

[msmith65]

You probably know the transmission has to be in neutral with the wheels chocked to check for play in the driveshaft.

 

[BuffaloXplorer]

Uh Oh!

While i thought that my "fix" to the slammin' tranny/pulsating abs issue was a little odd, i stand corrected. The replacement shackles did NOT fix the issue.

After quite a bit of stop-n-go city driving, and none of it driving lightly, it happened again this weekend. After i stopped driving for about an hour, it went away, but nonetheless, it's not fixed. I'm going to look into the tranny mount issue as soon as i can get under it.

I hope to get her into the tranny shop later this week to look into a couple trans issues i have. Once i do this, i'll let you know if it's somehow related.

 

[pax]

Yes, I checked it correctly in neutral before.
This time I took out the four 12mm u-joint bolts at the rear axle flange, lowered the drive shaft and pulled out the u-joint from the slip yoke. I checked the u-joint and there was no play at all, I was twisting and bending it on my hands, it move really easy, no binding, no metal filings around it, looked good to me.
I did had a slight problem, the slip yoke was tight, the drive shaft didn't want to come down after I removed the four 12mm bolt, I had to use a BFH to got it to separate from the flange. I don't know whether it was the rust on the flange holding it on or what. But I did clean the old grease off the slip yoke and filled the two half with fresh silicon grease, it is really slips and slides easy now.
I put it all back together, it was an easy painless 1 hour job. At least I lubed the slip yoke properly this time. I'll see if it fixed the problem.

 

[Rhett]

Mine will do the hard downshift ONLY if I have been running hard for a long time. I noticed it after coming out of the Rockies. It may be a function of my chip program, which does affect torque converter. (?)

 

[pax]

Well, on my way to lunch and the ABS pulse/clunk happened again. So it is not the slip yoke, not the u-joint. I don't know what caused it.
I just have to live with it until something break to know for sure. I am not going to replace stuff just to test it.
Thanks you for all your advise.

 

[pax]

Rhett, I didn't see your comment when I was doing mine.
Did your ABS pulse too while it clunks? Because my problem is exactly same as BuffaloXplorer, except mine can happen at anytime, regardless hard driving or not.

 

[BuffaloXplorer]

My problem has only occurred after hard, stop-n-go driving.

 

[Rhett]

Rhett, I didn't see your comment when I was doing mine.
Did your ABS pulse too while it clunks?

No, the ABS has never pulsed. With my chip turned off, I have never noticed any hard shifting.

Because my problem is exactly same as BuffaloXplorer, except mine can happen at anytime, regardless hard driving or not.

Like BuffaloXplorer, I only noticed this hard shift when the trans was really heated up after some hard driving. I may now install additional cooling, because I demand reliability above all else from my truck. Of course, in my case it may be all a function of the chip modifying the TQ conv lockup.