My 64 98 left the backyard for the 1st time in about a year today. And now I have trans issues. On deceleration, it feels like a manual transmission in too-high of a gear. It shudders and almost feels like it wants to stall.

If I manually shift it down to "S" (2nd gear?) on decel, it seems fine.

There are so many things I want to do to this car, and rebuilding the transmission isn't one of them. It seems that a lot of people on the internet are afraid of these transmissions. I know they're weird. I have a friend who has been in the transmission industry for probably 30+ years, I hope he knows enough to get us in trouble!

I'd be interested in hearing any advice on this.

 

Adam, I owned a 64 98 with the Slim Jim years ago. It was a beautiful car with a stout motor but that Slim Jim was the weak link.

Even if your friend has 30+ years experience with transmissions unless he has run across a Slim Jim before I'm sure it will be a strange beast to him. I don't think people are afraid of the Slim Jim, it's that it has a poor reputation that's well deserved.

You're best bet is to go to a more modern transmission. Here are the two major suppliers:

http://www.transmissionadapters.com/

http://www.forwhatyouneed.com/transm...conversion.htm

If you decide to do some troubleshooting first know that the manual throttle valve adjustment is critical. Good luck.

 

It's downshifting (and then up shifting) too quickly based on vehicle speed and load, and then 'bogs' which can stall the engine. Shorten the throttle to trans (not the shift) linkage about three turns to start, drive, check results on flat roadway. If you must make the adjustment under the hood, shorten the link rod going down to trans from bell crank, leave the carb to bell crank adj as-is to start unless you know it has been monkeyed, such as if a different carb has been installed. Good luck ~

 

Slim Jim complaint posts are common here, do a search if you have not already done so. No doubt it is a trans with some weird features but if in good shape and maintained properly it works fine for a regular street driven car. The immediate response by many is to replace it with a more modern trans but that is a complicated and expensive proposition. Assuming you have changed the fluid and filter and the fluid was not burned from major internal wear, Coldwar has mentioned the most common problem. The linkage adjustment and sync with the carb has to be just right or shifting issues like what you describe will happen. If the carb has been changed or the linkage eliminated it could be a major issue. Good luck.

 

The more reading i do, the more i realize that it also be an engine issue. I don't drive it much and it may need a bit fine tuning as well. The fluid level is full, but i think it is due for service. Reading some more, it says I need type A fluid, which is no longer available. I was gonna pick up a case of Dexron III fluid which i can still get. I'll certainly keep you guys updated.

Oh and I don't think i'll be doing a trans upgrade. I'll stick with the red-headed step child of transmissions.

 

Thanks for this advice- I know that the carb isn't original. I'll take some pics this weekend, if given the chance. I have a few other cars that need my attention 1st. Thank you again

 

Your engine needs a 4GC carb to be able to correctly adjust your Throttle Valve Rod (T.V. Rod) at the Bell Crank on the rear of your Engine. Other similar Carbs won't give proper adjustment for the pressure needed in the Transmission.

 

Well, it looks like I dodged a bullet. I started thinking about it and i thought i should better look it over a bit better than i did before just assuming it is a trans issue.

Turns out, the Holley carb had a major vacuum leak. PO put a vacuum cap on a large port on the passenger side of the carb. It apparently disintegrated and left a large wide open hole. Capped that baby off and took her for another ride. Shifts just like she did when I brought her home. I will be doing some much needed maintenance here shortly on the old girl.

Thanks for all the advice and help. On to the next issue!

 

Glad you dodge the bullet!

If that Slim Jimn is shifting fine make sure you take care of it and I'm sure it will give you many years of happy cruising.

 

Could you post some closeup pics showing how they adapted the trans linkage to a Holley carb? I bet a few people would be interested...