Been struggling with a rough running '97 HD 4WD 150k miles. Thought it was something in the injector/controls side but everything checked out OK then looked at the DMF. Have more than 7/8" movement. If you can look at the video in slo-mo it looks real ugly.

Read a lot on the pros and cons of a SMF vs DMF and am opting for the SMF. I'll be expecting noise and gear rollover particularly at low RPM/speed and maybe issues with the ZF5 which already has a bad 2nd gear syncro but maybe my trailer pulling is too much for the DMF ... at least when my son is driving it.

What do you think? Guess we will see.

 

I think you will be happy with the SMF. I have done this to 5 or 6 trucks, and gear roll over is minimal. The worst one is my 90 IDI, and that is only at real slow speeds, as idling around the pasture in low gear.

 

Rollover is hard to tell on a good trans.

That Luk kit from Rockauto is a great deal at about $300 shipped. Replaced the hydraulics too!

 

your video link does not work

 

Sorry about the video link, trying again. Maybe there is a trick I am not catching. I tested the link on the "preview post". It makes me save the file but then it is able to play OK. Personally I hate saving things like videos from sites so I don't do it. It's just a short clip and unless you can play it in slo-mo it's not so amazing.

Thanks for the comments.

 

I saw a video once of a guy moving the thing around by hand. Can you do that with yours?

FWIW, if I knew I had a DMF still in mine, it would be swapped pronto.

Make sure to service the unit while it is out of the truck. Mercon V seems to be the cheap 'off-the-shelf' fluid that is correct. Four quarts seems to be the ticket on a service.

 

 

Thanks Men ... for sure I'll do what I can with the ZF while it's out and all tips/suggestions are welcomed except I don't think I'll chase down the bad 2nd gear synco, I'm afraid that's above my pay grade. If I had the huavos maybe, but I hear the ZF is a lot more to tangle with than my old '51 F1 Deluxe 3sp w/granny tranny.

Hit Man ... yep, maybe I saw the same video which helped tip me off. I can move the plate almost 7/8" pretty easy and in slo-mo you can see in my video that my DMF is no longer running concentric. I'ts really bad.

In hind-site I can't believe I was chasing down the injection system. It always started right up, never stalled the harnesses ohmed out in spec and the freaken think shook so bad I could hardly see out my side mirror.

New SMF should be here in a couple of days. Next weekend I'll drop the tranny.
Thx for the input.

 

I recently rebuilt mine, not that big of a deal. It is pretty damned simple, just time consuming. Just expect to require more than syncros and bearings when you tear it down.

1st and 2nd are in the middle of the main shaft, so you need to correct tools to pull those gears off to install new syncros. 3rd and 4th can be tossed in really easy. I have a thread to make about my rebuild. Make sure your pedal box bushings are not wasted. Same goes for that lever that actuates the clutch master.

 

Thx again Hit Man. Actually I think I saw your tranny breakdown thread and your "simple" is over my top. Someone was thinking when they came up with that heim joint idea. I put one of those in 20k miles ago. Saw it first in this forum.

 

Update:
While on vacation my son installed the new SMF ... thx John ... the truck has never shifted so nice. Installed a Valair 13" x 1.25" SMF kit. Even my 2nd gear syncro is easier to deal with. Serviced the ZF while it was out. The fluid looked good and there was no metallic flakes or color in the oil. Also ran a magnet through the oil and did not pick up any debris.
Only issue which was expected is the added noise and boy is it noticeable particularly in neutral. With the engine running and the clutch disengaged (trans not spinning) everything is quiet. With the clutch engaged and trans spinning in neutral the noise from the ZF is very noisy. The ZF is not as noisy in any gear and driving with some load. I put some extra oil in the ZF but it did not make much difference.
Right now I will live with the noise and hoping the ZF will hang in there and I am not sorry for installing a SMF vs the DMF
Thanks everyone for your comments during this trouble=shooting process.

 

The noise will go away when the springs break in on the clutch hub assembly.