? Regarding 510 automatic Tranny

[jefe de jefes]

Has anyone experienced their 510 with automatic tranny jerk or lunge when put in gear , whether it be forward or reverse? I'm looking for some ideas before I head out and actually check for myself. I haven't had a chance with this crappy weather and less daylight. I know the obvious one would be to check the oil level. Any other ideas or tips?

[datto510]

Get underneath the car and turn the driveshaft by hand. If there is slop, check your U-joints. Is there any wobble when you are driving?

[jefe de jefes]

Ill check the u joints. I disconected the drive line the day I towed it home and didn't notice anything out of the ordinary. I didn't notice a wobble the one time I drove it either. I only went around my block twice because I'm not sure as to how much gas is in the tank. The PO owner disconected the gauge cluster to add Led's and I have yet to put it back together.

[MikeRL411]

While you're under the car check your engine mounts and the "rubber" transmission mount between the cross member and transmisssion. Slop will "clunk" on your driveshaft.

[420n620]

have you check the trans fluid and smell it to see if it smells burnt, also does it have a module, if so maybe its going bad. I'm not familiar w/ the 510's tran so just some ideas to check....

 

how about vacumm leaks..................... that would cause it to surge

Edited January 4, 2009 by 420n620
adding more to check list

[jefe de jefes]

I will be taking a look at it in a few hours. I'm hoping the fog picks up a bit.

[datzenmike]

Those are classic symptoms of low fluid or strangely too much fluid that has been foamed by contact with the moving parts in the transmission. Low fluid will cause the tranny to jump 'in and out of gear' on corners or inclines. Foam is compressible, causing the hydraulic pressure to drop that holds the tranny in gear.

 

What year is it? Two different types were used during the production of the 510. The Borg Warner BW-35 from '68-'71 and the Nissan Jatco 3N71B from '72 on.

 

The BW-35 has a downshift cable that attaches to the carb to signal full throttle and aid in a downshift. The cable is connected to the driver's front side of the tranny beside the shifter linkage. I don't think this would be the cause but it will confirm the tranny type.

 

The Nissan 3N71B uses a electrical signal from a switch on the gas pedal to help perform downshifts and has a metal tube to supply vacuum to a modulator valve to adjust shift quality. The vacuum modulator is located on the left center area of the tranny body. If this was off or leaking it might produce hard or rough shifting but not what you describe I think. The shift linkage on the 3N71B is on the right side.

 

 

Fluid should be bright RED and see through clear. Any discoloring and it should be changed. The cloudy or dark color is either from friction heat 'burning' the fluid or friction material worn off the many clutches or both. Fluid and filter should be changed every 30,000 miles so if you don't know, change it. HEAT is almost the only thing and certainly the most common cause of tranny failure. Heat breaks the fluid down and reduces it''s ability to protect the clutch surfaces. Keep the outside of an automatic clean so it can shed heat on hot days. Never tow with and automatic! ...but if you have to, change the fluid every 10,000 miles and inspect more regularly for discoloration of fluid. Buy an aftermarket trailer towing transmission cooler. A good idea even if you don't tow. They are about the same as one hour at a mechanic's rate. (think about that)

Edited January 4, 2009 by datzenmike

[jefe de jefes]

Its a 1971. I was planning on doing a carb swap with a weber 32/36 but now that you mentioned the cable connected to carb for downshifting I might not.

I also was thinking low tranny fluid, just haven't had a chance to check until later today.

What type of oil is recomended for these trannys?

thanks for the responses guys.

Edited January 4, 2009 by jefe de jefes

[datzenmike]

The cable only has to be adjusted so it's pulled out all the way at full throttle. This is just to let the tranny know when you are expecting full acceleration and will down shift (if applicable) for passing.

 

Usually a Dexron ATF is used but I don't know for sure about the BW-35 sorry.

[MikeRL411]

There were 2 Borg Warner automatic transmissions used. The British M35 made in [spelling?] Leicthworth] and the later Muncie Indiana American BW, with a swap out of the British M35 bell housing so that the USA bolt pattern on the American transmission boby adapted to the bolt pattern of the L16 engine. In other words, the American transmission from your Studebaker won't fit without swaping out the bell housing for a British one. Originally used ATF Type A, but Dextron is the approved substitute and works even better that type A. I have been using Dextron for 20 years.

 

The Muncie transmission uses vacuum downshift so lacks the mechanical downshift cable.

[datzenmike]

Thanks for the that Mike. All I have is the older British type info. I know the BW tranny for early 50's Stud and Ford were eventually made in Europe after '60.