1999 100 transmission issue

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Father of Crows
Oct 15, 2011
Portland, Oregon
181k on the ODO, no forwarning of any kind.
Driving along, suddenly a grind/whine and the engine revved.
This happened just as a big rig was passing me, and I thought it was noise from the semi at the time.
Kept driving on freeway, everything was fine.

Slowing down on the off-ramp, and it happens again. Whine, grind, no forward motion.
Grinds in all gears, no power forward or reverse. No ODB-II codes thrown for what that's worth.

Added some ATF while waiting for a tow, no change.

I'm pretty decent as shade-tree mechanics go, but I don't have any experience with autoboxes.
I have the FSM.
It's my daily driver, and I need it back in service ASAP to avoid ancillary costs of rental, etc.
Should I:
1. Buy a used lower milage tranny (about a grand delivered) and install myself. This doesn't look too hard based on the FSM.
2. Buy a tranny, have a shop install. I'm in Portland, Oregon, if anyone has recommendations. Normally I do all the work on my truck myself.
3. Drop the tranny, take it to a transmission shop for rebuild/diagnosis.
4. Run other diagnostics I don't know about but that you might tell me about....?

Looking to keep costs down, of course, but also would like the best answer from a future reliability perspective. It's an overland rig, and I'm thankful this happened in civilization...

Appreciate the help in advance,
How about keeping costs way down and it's probably not even the tranny?

Check your drive flanges, most likely a c-clip on the end of one of the CVs has slipped off and/or your flange splines are stripped. You can verify by locking the center diff and seeing if you can move the truck that way.
Sounds good to me (re. it's not even the tranny option). I have a known habit to assume the worst when it involves a component I'm not very familiar with....


I'll try this out ass soon as the tow drops off the truck and I'll let you know.

IF it does come down to being the transmission, the fastest most economical thing would be to find a low mileage used unit. Swap them out.

But as previously mentioned....check everything else first. It would be unusual for a transmission to make a 'grinding' sound, then quit, then start again.
Trunk monkey hit the nail on the head. Driver's side drive flange. Haven't taken it apart to see if the clip slipped off or what, but locking the dif and the truck drives around. Unlock, and grinding commences, def. coming from the driver's side.

Thank you both so much!

THE Best New Year treat for you from Trunk Monkey!

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