Rough Shifting on 84 Hurst/Olds

[carsofchaos]

Hey guys,
New to the forum and just picked up an 84 Hurst/Olds that performs a bit....strange. First let me say that the transmission was rebuilt in June of 2013, I have seen all the receipts for the work done so I believe this to be true. However, the shifting seems to have a random mind of it's own on frequent occasions. Sometimes, when I hit the gas after being stopped, it will accelerate as expected, then suddenly rev up about 1000RPMs, then jump back down to where it was. The car will also do this occasionally at highway speeds....I'll be cruising along around 70mph, approximately 2500RPMs or so, and it will suddenly rev up to about 3000RPMs, then go back down to wherever it had been. It seems to do this completely randomly maybe a couple times every 30 seconds, then not again for minutes on end.
The car is in good mechanical shape, low miles (89k) and is well sorted, but this is driving me nuts and making it not fun to drive. Not sure if it could still be something with the transmission (or TV cable perhaps) or TPS or something else. I usually work on older cars so this one is quite "modern" for me and a little out of my knowledge base. While i know it's almost impossible to diagnose a car over the internet, I'm seeing if someone else has run into this problem and what the cure might be. I also know the car was tuned up within the last 4-5 months.

Thanks,

Keith

 

[pagrunt]

Sounds like it is slipping. Even with receipts, the life the car lived with the last owner might be what you really need to know about. First thing to do should be check the transmission fluid to see if it is red or brown (darker it is, more likely it is bad.) Next check levels after getting the transmission warmed to operational. Another issue could be a clogged filter. Worse case, last owner had a heavy foot & loved to hammer hard on burn outs. Don't sound like TV cable, & these cars don't have a TPS. I take it you have TH200 4R .

 

[carsofchaos]

I have been in touch with the last owner, they only put about 5k on the trans after the rebuild....doesn't sound like he rode it too hard...everythings in nice shape...tires show almost no signs of wear....I DO know the trans had a problem when he bought it last year (from the original owner who had passed a few years back and it sat in a garage) which is why they had it rebuilt. Yes I do have the TH 2004R with Lightening Rod Shifters. It's weird I've read some threads that there is a TPS, others that say it doesn't have one. *scratches head*

 

[DoubleV]

these cars don't have a TPS.

Yes they do.

 

[jetsetw31]

these cars don't have a TPS.

Yes they do.

X2, they do have a TPS.



But it has nothing to do with the shifting problem of your transmission.
I agree with the rest of pagrunt recommendations.

Sounds like it is slipping. Even with receipts, the life the car lived with the last owner might be what you really need to know about. First thing to do should be check the transmission fluid to see if it is red or brown (darker it is, more likely it is bad.) Next check levels after getting the transmission warmed to operational. Another issue could be a clogged filter. Worse case, last owner had a heavy foot & loved to hammer hard on burn outs. Don't sound like TV cable. I take it you have TH200 4R .

 

[olds307 and 403]

Even up here they had the TPS, so yes x3. Check your TV cable, make sure it is adjusted right.

 

[carsofchaos]

Thanks guys I'll check the TV cable....the trans was rebuilt by AAMCO so I'm going to take the car there and have them check it out, since it's only been about 5k since the rebuild, if there's something wrong I hope they'll honor it (never dealt with them before).

 

[pagrunt]

these cars don't have a TPS.

Yes they do.

X2, they do have a TPS.

Sorry about my incorrect answer on the TPS, being years since dealing with the computers carbs totally forgot about them. Another thing that might be a good thing to have done regardless if the transmission has to come out or not is to get the cooler lines & cooler flushed. Forgot that may even be an issue not letting it cool properly.

 

[bill]

This reminds me of my trans except mine is even stranger...lol.... at cruising...you add a little power and the rpms DROP!...then raise up again...almost like the torque converter is slipping and when you add power it engages....weird...very weird. Trans builder said he would eliminate lockup...but I think he reused the lockup converter.... :shock:

 

[L92 OLDS]

....the trans was rebuilt by AAMCO ).

AAMCO wouldn't be my first choice for rebuilding a 200-4R. Hopefully they will stand behind their work and won't cause you more issues / expense. 200-4R's are finicky transmissions and I wouldn't trust ACME transmission to get it right.
Does the engine rev 1000 RPM higher in 4th gear at cruising speeds or while accelerating? Is the trans slipping or is it the lock up torque converter?