Slim Jim Transmission
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Slim Jim Transmission
Hi guys - just spent $$ on replacing the Master Kit on my '62 Starfire transmission and now I find the car revs out at 60-70mph (always about 3200 rpm) Can anyone help with what could be going on please ?? I am just throwing money at this hand over foot and now leaning towards a Ross Racing Engines TH400 replacement . Unfortunately here in NZ , I don't have access to parts and or advice readily , as there's not too many out here . Cheers
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Slim Jims are VERY sensitive to fluid level and linkage adjustment. Make sure the fluid is not low. A pint will make a difference. Get a set of adjustment gauges from Steve Westlake in Canada and a factory shop manual and check the linkage.
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What Oldsfan said! A few other thoughts...If your car has the stock 3.42 rear end gearing I think 3200 rpm is about right for 70 mph, high gear is 1 to 1. Is it noticeably slipping during slower driving? Also, is your speedometer reading correctly, if it is off you could be going faster than 70 resulting in higher revs. Low profile rubber with smaller diameter than stock can also do this.
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What Oldsfan said! A few other thoughts...If your car has the stock 3.42 rear end gearing I think 3200 rpm is about right for 70 mph, high gear is 1 to 1. Is it noticeably slipping during slower driving? Also, is your speedometer reading correctly, if it is off you could be going faster than 70 resulting in higher revs. Low profile rubber with smaller diameter than stock can also do this.
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Hi have drained the trans and refilled thinking it was overfilled but nothing . The TV rod has been adjusted both up and down but nothing has changed . Could be wrong but would the tool Steve has actually help this problem ??
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Please clarify what you mean by "revs out."
Do you mean that the car tops out at 70 MPH/3200 RPM and starts slipping/over-revving, or you're concerned about the RPMs at high speed and think something's wrong?
To echo the above post, >3000 RPMs at 70 is normal with the 3.42 gears in these cars. Driving one of these at highway speed for the first time can be very disconcerting, as the engine sounds as though it were about to go into orbit, particularly if you get on the gas at 70 and kick in the passing gear.
If your only concern is the RPMs at high speed, and you're otherwise satisfied with the shifting, your trans may well be functioning as intended. Save your money and leave it alone.
Using the TV rod adjustment tool would likely affect timing of shift points and passing gear downshift, but probably do nothing for a true slip at high speed.
Good Luck!
Do you mean that the car tops out at 70 MPH/3200 RPM and starts slipping/over-revving, or you're concerned about the RPMs at high speed and think something's wrong?
To echo the above post, >3000 RPMs at 70 is normal with the 3.42 gears in these cars. Driving one of these at highway speed for the first time can be very disconcerting, as the engine sounds as though it were about to go into orbit, particularly if you get on the gas at 70 and kick in the passing gear.
If your only concern is the RPMs at high speed, and you're otherwise satisfied with the shifting, your trans may well be functioning as intended. Save your money and leave it alone.
Using the TV rod adjustment tool would likely affect timing of shift points and passing gear downshift, but probably do nothing for a true slip at high speed.
Good Luck!
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Joined: Jul 2006
Posts: 331
My '62 used to slip in high gear. I had a leak at the one of the valves on the front pump. Once the fluid would get to be a pint low, it would slip. Adding a pint would rectify it. I finally fixed the leak. Something is allowing it to lose pressure in high gear. If it's not fluid level, it could be an incorrectly installed filter or something internal.
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Posts: 5
Please clarify what you mean by "revs out."
Do you mean that the car tops out at 70 MPH/3200 RPM and starts slipping/over-revving, or you're concerned about the RPMs at high speed and think something's wrong?
To echo the above post, >3000 RPMs at 70 is normal with the 3.42 gears in these cars. Driving one of these at highway speed for the first time can be very disconcerting, as the engine sounds as though it were about to go into orbit, particularly if you get on the gas at 70 and kick in the passing gear.
If your only concern is the RPMs at high speed, and you're otherwise satisfied with the shifting, your trans may well be functioning as intended. Save your money and leave it alone.
Using the TV rod adjustment tool would likely affect timing of shift points and passing gear downshift, but probably do nothing for a true slip at high speed.
Good Luck!
Do you mean that the car tops out at 70 MPH/3200 RPM and starts slipping/over-revving, or you're concerned about the RPMs at high speed and think something's wrong?
To echo the above post, >3000 RPMs at 70 is normal with the 3.42 gears in these cars. Driving one of these at highway speed for the first time can be very disconcerting, as the engine sounds as though it were about to go into orbit, particularly if you get on the gas at 70 and kick in the passing gear.
If your only concern is the RPMs at high speed, and you're otherwise satisfied with the shifting, your trans may well be functioning as intended. Save your money and leave it alone.
Using the TV rod adjustment tool would likely affect timing of shift points and passing gear downshift, but probably do nothing for a true slip at high speed.
Good Luck!
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Joined: Jul 2006
Posts: 331
The "Roto Hydra-Matic Diagnosis Guide" says the following, which I will leave for you to contemplate...
"A slipping condition in 2nd and 3rd only can be assumed to be related to the front clutch or its circuit. The front clutch is applied in 2nd and 3rd speed only, and although the coupling is used in 3rd speed, the coupling can be checked as O.K. in 1st and Reverse."
"Sequence for Hydra-Matic Diagnosis Procedure
1. Check and correct oil level.
2. Check and correct manual and T.V. linkage.
3. Road test
4. Air check procedure
5. Control valve assembly check"
"Correct throttle linkage adjustment is important for obtaining the correct throttle pressure at any given throttle opening. Over 75% of all customer complaints on improper transmission operation can be eliminated by the correct setting of the throttle linkage. Incorrect throttle pressure can result in
1. Improper shift feel, harsh or slipping
2. Incorrect oil pressures
3. Missing shifts
4. No downshifts
5. Transmission noises."
And, finally...
"Condition - Slipping - All Ranges
1. Low oil level - correct oil level, check for leaks.
2. Low oil pressure - see oil pressure section
3. Coupling - see air check section"
Regarding #2, low oil pressure, there are 10 possible causes - oil level; wrong or stuck boost plug; wrong, stuck or damaged pressure regulator valve or spring; damaged or missing strainer O-ring; misaligned manual valve; oil cavitation or foaming; internal leak; sticking valves in the control valve assembly; low output from the slide rotor in the front pump; or, the ball check in the control valve assembly (which is for low pressure in low range only).
"A slipping condition in 2nd and 3rd only can be assumed to be related to the front clutch or its circuit. The front clutch is applied in 2nd and 3rd speed only, and although the coupling is used in 3rd speed, the coupling can be checked as O.K. in 1st and Reverse."
"Sequence for Hydra-Matic Diagnosis Procedure
1. Check and correct oil level.
2. Check and correct manual and T.V. linkage.
3. Road test
4. Air check procedure
5. Control valve assembly check"
"Correct throttle linkage adjustment is important for obtaining the correct throttle pressure at any given throttle opening. Over 75% of all customer complaints on improper transmission operation can be eliminated by the correct setting of the throttle linkage. Incorrect throttle pressure can result in
1. Improper shift feel, harsh or slipping
2. Incorrect oil pressures
3. Missing shifts
4. No downshifts
5. Transmission noises."
And, finally...
"Condition - Slipping - All Ranges
1. Low oil level - correct oil level, check for leaks.
2. Low oil pressure - see oil pressure section
3. Coupling - see air check section"
Regarding #2, low oil pressure, there are 10 possible causes - oil level; wrong or stuck boost plug; wrong, stuck or damaged pressure regulator valve or spring; damaged or missing strainer O-ring; misaligned manual valve; oil cavitation or foaming; internal leak; sticking valves in the control valve assembly; low output from the slide rotor in the front pump; or, the ball check in the control valve assembly (which is for low pressure in low range only).
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