no engagement in any gear help please!

[big sally]

hello I'm new to this forum for starters I have a 1988 gmc jimmy Sierra classic 5.7 350 & 700r4 tranny
so my issue is I was driving and suddenly the truck was not moving on its power engine was on and raving but not moving I pulled over and everything seemed in tact and nothing was visibly leaking after a few min. I put the truck in 4wd high and nothing I put it in 4wd low and it engaged after that I put back into 2wd and I was Able to drive away, a few hours later the same thing happened again and still nothing leaking the truck has always shifted well the fluid is full but is more on the purple side then pink
this truck is my daily and I am not a mechanic but am Able to handle simple to moderate jobs

 

[PrairieDrifter]

I’d check to see if the TV cable is in good condition and good working order and possibly even check the throttle valve for proper operation, but that requires dropping the trans pan. If that’s not the issue I would say the trans is toast but I’m not a transmission master so just my 2 cents

 

[HotRodPC]

Normally transfer case shifting isn't going to make a difference unless you're having some kind of transfer case failure.

 

[crazy4offroad]

My first guess was broken sprag but since you got it going again it would sound like a leaking or stuck pump ring that came un-stuck. By the way revving it when it's slipping will kill your clutch packs, and may have already reduced how much material they have since you mentioned discolored trans fluid. I foresee a rebuild in your near future.

 

[74 Shortbed]

I'd be tearing it down before anymore damage can occur...

 

[smoothandlow84]

I second the mandatory teardown....unfortunately, losing forward or reverse gears is usually the first sign of needing a rebuild. I would be very wary of any color other than bright red trans fluid. When I lost my revese gear, the forward were soon to follow. My 700r4 ended up requiring a complete rebuild. The pump was shot, the races and bearings were toasted and even my transmission guy was shocked that he was able to move the truck up on his ramp under the trucks own power once the internal damage was discovered. The longer you try to use it, the more damage will occur.

 

[big sally]

thanks for all the responses it hasn't happened again since i will be giving the 700r4 a service including filter and gasket, reaper mentioned checking the throttle valve for proper operation by dropping the pan can you or anyone explain how that looks and how it should be? i am unfamiliar with this pics would be awesome if anyone has any
thanks alot everyone i am greatfull for everyones imput

 

[74 Shortbed]

When you drop the pan look at what the cable is hooked up to, that lever moves the the throttle valve in it's bore.

You must be registered for see images

 

[Old77]

thread moved to the proper subforum

 

[big sally]

how do I adjust it or know that its in its proper position?

 

[74 Shortbed]

how do I adjust it or know that its in its proper position?

Here ya go.

https://www.youtube.com/results?search_query=how+to+adjust+700r4+tv+cable

 

[big sally]

Thanks it was big help I did the tranny service eveeythin went pretty smooth but im still having the same issue if I drive it a little to hard it pops out of gear and I have no engagmemt till I put it in 4wd then back to 2wd anybody have any other suggestion?

 

[MrMarty51]

Does the transmission actually pop out of gear, or the transfer case ?
Welcome to the forum Sally.

 

[Honky Kong jr]

Here ya go.

https://www.youtube.com/results?search_query=how+to+adjust+700r4+tv+cable

Don’t watch the Monster ones their transmissions only last as long as those videos do lol

 

[74 Shortbed]

Don’t watch the Monster ones their transmissions only last as long as those videos do lol

That's if you get a good one, lol.