Th350 reverse issue and thoughts

[1980Spartan]

I have a 1980 GMC 1500, with a 350 sbc with a th350 trans. The trans has some issues shifting into reverse when it's just getting going. Picks up drive and low gears fine. If I let it sit for about 10 minute or if I drive it around the block, reverse will show up. I've heard th350's have had this issue and eventually will start to lose drive gears... im sure there are some who are far more experienced than I who could shed some light on it. A search showed minimal results.

Anyways, I'll probably end up pulling it, which then leads to the next question... do I rebuild it, pay for it to be rebuilt, or put something else in it? Where I live the freeway is 70mph, so something with an OD might be nice, and I'm not super concerned about money.

I'm just curious what your thoughts Are!

 

[crazy4offroad]

If the fluid is dark and it has no engine braking in L1, the low/reverse clutch pack is likely smoked. If not, there could be some sludge in the valve body making them stick.

 

[Jrgunn5150]

If the fluid is dark and it has no engine braking in L1, the low/reverse clutch pack is likely smoked. If not, there could be some sludge in the valve body making them stick.

That is the quickest way to tell, throw her in low from a nice 15 mph roll and see if it hauls down or not.

 

[1980Spartan]

I'll try the run in 1st and see what I get. I appreciate the info. If it's clutch packs that's a rebuild through and through.

 

[bucket]

The stock trans in my '84 had those exact symptoms, and it was daily driven like that for several years. It slowly got worse over time, near the end reverse only worked once everything was fully up to temp. Forward gears always worked fine.

 

[1980Spartan]

The stock trans in my '84 had those exact symptoms, and it was daily driven like that for several years. It slowly got worse over time, near the end reverse only worked once everything was fully up to temp. Forward gears always worked fine.

Interesting.... I haven't had the truck that long, but I'm getting the idea it's been like this for awhile. When I bought it it had been driven that day so reverse was in good working order. The P.O. said reverse was "a little soft" in which I asked what be meant and he just said it takes a little bit to go into gear.... lol

Your experience gives me a little more confidence I won't find myself with a crippled trans anytime soon though.

All in all it's one of those things where I'm trying to figure out some priorities on what I'd like to tackle next.

 

[Jrgunn5150]

Interesting.... I haven't had the truck that long, but I'm getting the idea it's been like this for awhile. When I bought it it had been driven that day so reverse was in good working order. The P.O. said reverse was "a little soft" in which I asked what be meant and he just said it takes a little bit to go into gear.... lol

Your experience gives me a little more confidence I won't find myself with a crippled trans anytime soon though.

All in all it's one of those things where I'm trying to figure out some priorities on what I'd like to tackle next.

It won't leave you stranded like that, just get progressively worse lol.