Hello,

I have a Roto Hydramatic 375 which shifts fine, but seems to be making a rattling noise inside. I am afraid it may go any time soon, and was wondering if anyone knows of a reputable transmission rebuilder that has done Roto Hydramatics in Texas (Dallas area preferably)?

How difficult would it be to try to rebuild it myself if i got the time, the rebuild kit? Has anyone tried this?

Thanks for your help

 

I trust Greg Ducato at Phoenix Transmission in Weatherford, TX west of Ft Worth. Greg is the most knowledgeable, experienced and honest transmission guy I've met. I'm sure that there are competent builders in the Dallas side as well, but you asked and there is my answer. Feel free to look them up and give him a phone call to ask questions and satisfy concerns, I'm certain he would be happy to chat cars with you.

 

Plano Transmission in Plano, Talk to Jeff.

 

Just a thought, but your rattling noise may be due to worn or cracked springs on the damper plate.

 

X2 on Jeff and Plano Transmission. I have dealt with him for years and there is nobody with a better reputation. He rebuilt the transmission on my 94 Corvette and one of the parts went bad (not his fault). He sent a wrecker and picked it up and rebuilt it. Did not cost me a dime. I don't recommend a lot of shops but he is one I recommend for sure. I know there are lots of other good shops but I would not use anybody else.

 

Hello All,


Thank you so much for your replies. I have ordered a new damper plate and will be trying that out first since that is the cheapest option. Once I rule out the damper plate I may still need a transmission rebuild if the noise still there.


Glad to see there are so many Oldsmobile folks in Dallas. I bought this old 1964 olds 98 because my Dad had an oldsmobile when I was a kid. It has been fun to work on it so far.

 

I would also replace the input/pump shaft seal on the transmission while its out. Did you inspect the damper plate/springs before ordering it ?? Do you have a manual that explains the rebuild process for the transmission. I would leave an actual rebuild to a shop that has experience in this type of transmission if you need to go there. Looks like other members have some good recommendations on shops that you could call.

 

i found that it's best to call around on old obsolete transmissions (I had a 62 Ford Futura with a 2 speed auto), the first retraction on the phone tells you wether anyone at a particular shop knows anything about them. I found after a few calls everyone started recommending a particular shop that have a transmission builder that was as older than the car and he did a great job.

 

Hello. I had a 64 Olds 98 many years ago. I rebuilt the transmission myself while taking a college course. The professor and the local transmission shop owner were surprised when they saw my transmission. The Slim Jim Rotohydramatic is a rare transmission. If you take it to a shop make sure they know what they're getting into. Once they build it they have to set the throttle valve properly for it to shift right. If you decide to rebuild it yourself make sure you have Factory Service Manuals for your car. You can probably find parts for it at Fatsco transmissions.

 

Hello All,


The damper plate looks ok, but there are several springs that rattle around. When I called to order a new Damper plate the guy at Fatsco said that some of the springs do move, but that it is very possible that some of the clutch mechanism inside is broken. The new plate is 190$, so I decided to order it anyway. I have replaced both the front and rear shaft seals in the transmission.


Once I get the new damper plate I will re-install everything and try out again. As I mentioned the transmission shifts fine but I kept hearing rattle coming from the bell housing/transmission area.


I appreciate all your help. You are right, the slim jim is no ordinary transmission. I talked to a guy at my work who took a class on rebuilding Auto transmissions and when I showed him the service manual of the slim jim, he said it is different than most auto trans and he was shocked that there was not external torque converter

 

I also replaced the damper plate on my 64 Olds 98. As I recall, a few of the springs were broken on mine.

Let us know if you're able to fix the rattle.

 

I'm going to throw this out there, but could it possibly be a loose ring gear? I've never heard of this happening, but just thought I would mention it. There are also, from what I've read in my service manual, balancing pins in the flywheel that are staked in, and sometimes they are not staked for whatever reason. According to the manual, the pins are located on the outer circumference of the flywheel. And I imagine, you've gone over every thing attached to the engine and transmission with a wrench to make sure nothing is loose? Loose components can make all kinds of noises. Keep us posted on how things turn out.

 

X2 on Greg and Scotty out at Phoenix in Weatherford. Been dealing with them for about 25 years.