Okay, here's the deal....

Replaced the stock 700R4 in my 84 Trans Am with a rebuilt one today. We had to swap out the tailshaft and the speedo gear. So, we took out the speedo gear, removed the tailshaft, and then removed the gear ring that was around the tailshaft (that drives the speedo gear) and put them all on the new tranny. Put everything back together and we have the following 2 problems:

1) The shift timing. I know how to adjust the shift timing and we were able to improve it, but not fix it comepletely. The car shifts somewhat correct between 1st and 2nd, but then it shifts to 3rd waaayyy too quick. We reused the TV cable from the old tranny...could it be stretched? We also tried the technique of holding the plunger on the TV cable assembly down and pushing the gas pedal down....however it made the car shift way way too late. Ideas?

2) Other problem...the speedometer worked in the car until about halfway home...then it just quit. Would that be from the speedo gear not making contact with the ring gear inside? Thoughts here?

Other than that, the car runs great!

Thanks,
Joe

 

UPDATE: Shifting is fixed; speedometer still doesnt work.

 

firebird

I had a 84 once and had it's 700r4 rebuilt and it's speedo quit working a few miles from the shop. the cause for mine was this. on my 84 it used a aluminum speedometer gear housing or something like that but the shop put some plastic housing back in the trans. the two can't be interchanged for some reason and if you do it the plastic one shatters. like your's mine also shifted weird and searched for a gear till speedo was fix.

I am not sure of the name of this aluminum part since I don't know much about automatics maybe someone else can help

 

I don't think that's the reason. My buddy and I did the tranny ourselves and we swapped the tailshaft, speedo gear, and the nylon gear on the tailshaft that is driven by the speedo gear to the new tranny. The tailshaft is aluminum. I'm thinking that maybe the speedo gear lost contact with the nylon gear inside. Guess I'll have to crawl back under there and see....

Joe

 

Kind of far out there in the years but. I have a 1991 t/a with a 700r. Put new TV cable on it and readjust it and new filter. ( I pretty decent with working on vehicles. ) but i am having the same problem as u. My car shifts WAY TO soon. What did you do to fix yours. I've searched this board for HOURS and tried so many different things. Maybe what u did will help me

Thanxs, and sorry to jump in on your thread and not beable to help with your question

Derrick

 

I just adjusted the TV cable next to the carb until it ran correctly.

I fixed the speedo too...turns out the gear on the tailshaft came loose and wasnt making contact with the speedo gear.

Joe