TH400 Problem with Reverse

[Armada]

On a 1009 I just picked up, the transmission forward gears work well but when I put it into reverse, the tranny slips and the truck will hardly move backwards. There is no abnormal noise. The fluid level was about a quart low so I topped it off and still the same prblem. The transmission is bone dry underneath, so no leaks, and the fluid is pink with no burnt smell. Any ideas on what I should check? Modulator, vaccuum, etc......? I want to make sure it's not something simple before it gets removed.
Thanks

 

[Towman2277]

Sometimes a filter change will make the difference needed. I had a turbo 350 have the same symptoms, and a fluid and filter change fixed the problem.

 

[MATT]

Post this on TheDieselPlace.com they have a tranny section

 

[gasser]

Well, I know with the TH350's, the reverse is a band - no clutch packs. So in the few times that I had major slippage and when finally TH350's went out, I always had reverse.

Now, with the TH400 - I am not sure if the above is true. Sounds like the pressure works a bit different between the two models ...

Oh hell, I am not even sure why I posted all this then ......


-graham

 

[ZiggyO]

Hello,

I had an issue with my truck with reverse thats almost identical to your problem....... I found it to be the following----- it seems that the last person to have serviced this thing before it went to drmo neglected to replace the little O ring that goes on the side of the pickup tube going into the trans body when replacing the trans filter...... this somehow allowed enough air to enter to cause reverse to go out in that truck but it wasnt enough to cause any significant change in forward gears...... All it took was a $0.59 O ring (and a new trans filter while i was at it) and the thing runs perfectly now (Incidently this was one of two trucks I got from the same auction event that each had some really small thing which resulted in them being deadlined-- bad for them but great for me )

Ziggy

 

[Armada]

Thanks for the tips. I'm hoping it's the $0.59 o ring that's missing, that would be in my budget..lol
Makes sense though. It would act like a restricted filter.The fluid in the tranny is very fresh, so maybe a fluid change was made recently and the seal got missed causing the rev to go out. Or maybe the reverse went out first and they changed the fluid and filter and it didn't help. Hope it's the former. I'll pull the pan and take a look.
Anything else I should check?