Hi.1998 F-150 4.6L 4x4 with the 4R70W 4-speed auto. Recently drained and filled the ATF, replaced the filter, and also did the transfer case fluid. Notably, the ATF was sludgy and had a bunch of metal shavings (no big pieces).

Was planning on going "softroading" this weekend and thought I should at least try engaging 4x4 with the new fluid in the transfer case. Did the following:

• Stopped (been running for a good 20 minutes), put in neutral
• Pulled transfer case shift lever into 4H (dash light indicates so)
• Immediately pulled transfer case shift lever into 4L (dash light indicates so)
• Hear a big "clunk"....crap (well, now I know that it's supposed to do that)
• Put back into 2H

Now at 2H, it will go forward but when shifted into reverse, it won't move at all and there's "grinding".
When put back into 4H and into reverse, it will move and there's no grinding noise. However, when moving forward any faster than approximately 10kmh, there's a "grind" even at 4H.

Did I do something wrong with how I shifted the transfer case? Any ideas as to what the problem could be? Thinking that since it backs up in 4H, the problem is (hopefully) not with the transmission.

Thanks.

 

I think your issue is with the transfer case. Make sure the stick is all the way forward. Each year before winter I lube the shift mechanism on my t-case because it gets bound up a little from non-use the rest of the year.

Take it from 4H to 2H a couple of times after you lube it... I bet it resolves your issue.

 

Hey, good catch. Forgot to mention that the shifter was pretty hard to move and get into place. Couple of questions:

- What type of lube do you use? Looking around Google and people are saying to not use WD40. Do you think PB blaster/penetrating lube is fine?

-When you shift back and forth between 2H and 4H, do you move the truck at all to let the TC engage or do you just stay in place?

Thanks.

 

I use Kroil for lube, my personal favorite penetrant. I agree, WD-40 will work, but it won't last as long.

I also stay stopped for all t-case shifts. For 4 Low, I always put it in neutral as well. I think I read that in the manual, or maybe on the sticker on the back of the visor? Can't remember.

 

You were right. I sprayed the linkage with PB blaster, let it soak for 2 hours and tried again. It turns out that the shifter wasn't fully in 2H when I tried to reverse - there was just a lot of resistance due to the rust in the linkage.

Have you replaced one of these linkages yourself? Doesn't seem to be a lot of space to work under there but I see some people cut out a hole in the floor of the cab. I plan on doing a little bit of offroading so I'm thinking about doing it soon.

 

I've never swapped one, no. I have removed one once though, and sold it on Ebay. The truck had the floor partially cut though.... and I think someone on here (I'd say a year ago) replaced one and had to do something with the trans hump to get it out.

 

Btw, thanks for the input. Saved me a trip to a trans shop.

 

No problem. I'd hate to see what they'd say, and charge!